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MUSEUM OF NATURAL HISTORY
The University of Kansas
Law renee, Kansas

NUMBER 40, PAGES 1-60 SEPTEMBER 10, 1975

SYMPATHY AND INTERRELATIONSHIPS
IN COSTA RICAN ANOLES

By

Henry S. Fitch

Abstract

Seventeen of the known 25 species of Costa Rican anoles (Anohs)
were included in a field study carried on at 20 localities inter-
mittently between October 1967 and March 1974. The separate
species were found at from one to nine of the study areas and
occurred syn topically in many different combinations. In the re-
gion of this study a "modal" anole lives in forest or forest edge,
is about 50 mm ( S-V ) in adult length, the male slightly larger
than female and having a brightly colored dewlap which the
female lacks, is tree-trunk-to-ground oriented, takes a great variety
of insect prey, has a temperature preferendum between 26 and
28 and is dull-colored with female polymorpliism in pattern. Most
species deviate somewhat from tliis modal type. However, in-
stances of co-occurrence with use of the same resources by two
or more species are common, and competitive relationships of all
degrees seem to exist. In any sympatric species-pair the selective
pressure generated by mutual competition is different for the two
species involved, because of differences in size, aggressiveness,
population density, and the ratios of sympatric to allopatric areas
in overall geographic ranges.

Introduction

In Costa Rica, a tropical area of about 50,600 km- with highly
varied terrains, climates, and plant associations, lizards of the genus
Anolis ( anoles ) are abundant in numbers of individuals and species.
There are extensive areas within the country that, because they are
too cold, too dry, too barren or too greatly altered from original
conditions by agriculture or other human activity, lack these lizards,

2 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

but other extensive areas are occupied, often with the potentially
competitive co-occurrences of two or more species.

No two anole species coincide exactly in area occupied, or in
habitat. Where there is syntopy obvious differences always exist
between the associated species, in such traits as preferred perch
height, affinity for shade or sunlight, body size and various aspects
of behavior. Nevertheless, these species often seem to be using the
same resources, with varying degrees of overlap. Numbers of
species, combinations of species, and intraspecific population den-
sity and structure all show variation in time and space; hence, inter-
specific interactions are extremely complex. The following account
is a preliminary attempt to assess these interspecific relationships.

Anolis has well over 200 species, mostly Neotropical but with
some in the temperate zones. The majority have at least some
arboreal tendencies, and are inhabitants of warm, humid climates.
There is much diversity in the West Indies, with a host of species
endemic to single islands or groups of islands. The insular species
have been the subjects of intensive studies that have contributed
substantially to an understanding of evolution and ecology, and thus
have in many instances clarified the phylogenetic and competitive
relationships of kinds that live in sympatry.

Much less field work has been done with the even more numer-
ous mainland species, and in general their relationship and ecology
remain poorly known. Slower progress in studies of the mainland
species results from the fact that they are distributed over a much
greater area than that of all the West Indian islands combined, that
they generally occur in much lower population densities, and that
their ecological relationships are perforce more complex than in
kinds living in the relatively simplified insular ecosystems.

Most of the numerous anole species have many moiphological
and ecological traits in common. They are relatively slender, light-
bodied lizards, with long, attenuate tails, and with transverse la-
mellae more or less developed on the penultimate phalanx of each
digit, as a scansorial adaptation. Unlike most other iguanids, they
are largely independent of specific escape shelters and avoid cap-
ture by a combination of cryptic color and behavior, agility, and
dependence on dense cover such as vines, epiphytes or leaf litter.
Also, unlike most other lizards they normally lay only one egg at a
time, with eggs produced at fairly regular intervals throughout the
year, or a major part of it, corresponding with the wetter and/ or
warmer seasons. A typical or modal anole species is small (40-69
mm S-V), scansorial, tree-trunk-to-ground oriented, and with some
sexual dimorphism (male larger, with larger and more brightly
colored dewlap ) . In the optimum habitat of tropical forest or forest
edge, with several syntopic species whose co-existence is made
possible by average differences in choice of food, perches and other

COSTA RICAN ANGLES 3

environmental resources, interspecific competition may be intense.

Although anoles thrive best in warm and humid regions, some
such regions have a much greater variety of species than others.
On the mainland the greatest concentrations occur in the coastal
regions of Colombia and Ecuador, in Costa Rica, and in extreme
southeastern Mexico and adjacent Guatemala. In all three instances,
high mountain ranges create a spectrum of climatic gradations and
vegetational types that have resulted in evolutionary diversification.

In Costa Rica, comprising less than 4% of the mainland area
occupied by the genus, there are 25 currently recognized species,
perhaps a greater concentration than in any other area of com-
parable size. Two species, Anolis godmani and A. aUae are of
uncertain status, the former being known only from the original
description in 1885. A. microtus and A. pachypus are little-known
montane species. They were not found in the course of my field
work, nor did I find A. frenatus, a giant tree-top anole, nor the
recently described A. chocorinn and A. vocifenins. A. toansendi,
endemic to Cocos Island in the Pacific Ocean more than 300 miles
from the mainland, was not included in my study.

The remaining 17 Costa Rican species were the subjects of this
study (Table 1). The object was to observe each species through-
out its annual cycle in areas of sympatry, to determine similarities
and differences and to assess the amount of overlap in use of essen-
tial resources, and to estimate the effect of overlap on the local
populations involved.

Materials and Methods

My interest in Costa Rican anoles began in 1965 while I was
involved in field work as part of the Fundamentals of Tropical
Biology course offered by the Organization for Tropical Studies;
some specimens and data were collected during my participation in
the course. More data were collected from October 1967 to March
1974.

The study involved finding suitable areas representative of
diverse habitats, where anoles were at least fairly common, and
sampling local populations throughout their annual cycles. Sam-
pling included sexing, measuring (snout-vent and tail length) and
weighing those captured, to determine the usual adult size and
size-range of adults. Reproductive condition was determined from
external appearance or from occasional individuals killed and pre-
served. Attempt was made to assemble sufficiently large samples to
permit analysis of population stmcture on the basis of sex ratio
and age-groups. Sexual dimorphism in size, and individual and
geographic variations in size, morphology, and color pattern were
noted.

4 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

At most of the study areas (not Rio Corobici, Rio Sandillal,
Cartago, Dominical, Quepos, nor Las Cruces) capture-mark-recap-
ture programs were carried on in an attempt to determine growth
rates, population turnover and longevity. Marking was accom-
plished by toe-clipping which always has deleterious effects and
may have caused temporary stunting of growth. No individuals of
aquaticus, hiporcatiis, insignis or polylepis were marked, and little
was learned from the marking of carpenteri, lemurinus, pentaprion
and sericeus because of the small numbers of individuals involved.

Body temperatures and adjacent air temperatures were read to
the nearest tenth of a degree with a Schultheis quick-reading ther-
mometer. With due consideration of time of day, weather condi-
tions, activity of individual, and distribution of shade and sunlight,
the readings were used to determine the preferenda and range of
voluntary tolerance for each species. Observations on behavior in-
cluded heights and diameters of the perches used, methods of es-
cape or concealment, and interactions with other anoles of the same
or different species under varied conditions, with heterosexual and
homosexual combinations.

Study areas (Fig. 1; Table 1) were selected to represent con-
trasting types of habitat, including broadleaf evergreen forest in
the humid lowlands of the Caribbean versant, lowland seasonally-
dry forest in the Pacific versant, montane forests, plantations such
as coffee, banana, cacao and coconut, and, in even less natural
situations, fence lines, cement walls, and bushes and trees in sub-
urban lots.

Field work in late 1967, 1968, 1969 and early 1970 was at Playas
del Coco, Sardinal, La Irma, Boca de Barranca, Vara Blanca, Haci-
enda El Prado, San Jose, Quepos, San Miguel de Sarapiqui, Tur-
rialba and Beverly. In 1973 and early 1974 field work was on study
areas at Rio Corobici, Rio Sandillal, Rio Abangares, Rio Congo,
Monteverde, Dominical, Las Cruces and Finca La Selva.

Some of the findings resulting from my field study were pub-
lished in earlier papers, especially those concerning Anolis tropi-
dolepis in its upland habitat of cool moist cloud forest at Hacienda
El Prado (Fitch 1972), and those concerning A7iolis cupreus at the
various localities in Guanacaste, Puntarenas and San Jose provinces
where it was studied. Shorter accounts of the range, habitat and
general habits of several of the species were included in "A field
study of Costa Rican lizards" ( Fitch 1973a ) .

In my field study relatively large amounts of data were obtained
for the commonest and most widely distributed species — Anolis
cupreus, A. limijrons, A. humilis and A. intermedius, in that order.
Relatively small amounts of data were obtained for the other spe-
cies, especially for A. biporcatus, A. carpenteri, A. insignis, and A.
pentaprion, which were found on only a few occasions. Although I

COSTA RICAN ANGLES

Fig. 1. — Map of Costa Rica showing field sites where anoles were studied:
b. Boca de Barranca, c. Cartago, d. Dominical, f. Finca La Pacifica, Rio
Corobici and Rio Sandillal, g. San Miguel de Sarapiqui, h. Hacienda El Prado
and Vara Blanca, i. La Irma, Rio Congo and Rio Abangares, j. San Jose,
1. Bev'erly and Limon, m. Monteverde, p. Playas del Coco and Sardinal, q.
Quepos, s. Finca la Selva, t. Turrialba, v. San Vito, Finca Las Cruces.

obtained little information about either A. polylepis or A. sericeus
in this study, I was able to compare both kinds with other anoles
because of the thorough field study made by Andrews (1971a; 1971b)
on A. pohjJepis, supplemented by the observations of Clark (1973)
and Hertz (1974), and because A. sericeus had been studied in south-
ern Mexico (Henderson and Fitch, 1975), where it occurs in much
higher densities than it does in Costa Rica.

Description of Areas
Fig. 1; Table 1; PI. I

LOWLAND HUMID EVERGREEN FOREST OR PLANTATION

Finca La Selva, Heredia Province. — This field station, owned
and administered by the Organization for Tropical Studies, includes
primary rain forest, and areas disturbed and altered to varying
degrees, with some clearing for buildings and plantations and for

6 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

experimental procedures. Major habitat types are: (1) primary rain
forest, covering both steep, well-drained slopes and flat swampy
land, traversed by broad foot trails and by several streams; (2)
cacao groves, no longer tended and beginning to revert to forest,
having a closed canopy, heavy leaf litter, and occasional large for-
est trees; (3) an arboretum, with native forest trees of all sizes,
some natural growth, and some planted. Other vegetation was
periodically cut by macheteros, and the trees were spaced so that
the canopy was discontinuous.

My data were gathered from many places within a radius of 1
km around the station headquarters and they repr(^sent all the types
of habitat mentioned above. However, efforts were most concen-
trated on an area of approximately 1 ha in an old cacao grove
about 0.5 km north from headquarters. Populations of both Anolis
hiirmlis and A. Umifrons were high. A. capita was found there
occasionally, and A. lionotus occurred along a small stream border-
ing the area.

Beverly, Limon Province. — This flat lowland area on the north
side of Rio Banano, 8 km airline south of Limon, was mostly in
cacao groves having many scattered large trees of the original for-
est. Some of the groves were untended and had grown up to dense
thickets. There was heavy leaf litter from the cacao and other trees.
There were sluggish streams meandering through the areas, which
were also broken by a railway, a road, occasional patches of pas-
ture, and clusters of human dwellings. Anolis humilis and A.
Umifrons were both abundant in the cacao groves, but A. huinilis
was concentrated about the root buttresses of large trees in deep
shade and A. Umifrons was concentrated along edges, even in the
grass of adjacent pastures. A single A. carpenteri was seen at this
locality.

Limon, Limon Province. — In the city park at the ocean front
giant fig trees, having massive trunks and buttressed roots provid-
ing innumerable holes and crevices, were inhabited by AnoUs
cristateUus.

TurriaUxi, Cartago Province. — Field work was carried on mainly
on the grounds of Instituto Interamericano Ciencias Agricolas, near
the headquarters in planted groves, with a variety of tree species in
open stands and with ground vegetation trimmed from time to time.
AnoUs Umifrons was abundant, and A. biporcatus was found occa-
sionally. In the gorge of the Rio Reventazon A. carpenteri was
found (on one occasion only) on lichen-covered areas at the edge
of the river, and A. hiimiUs, A. lemurinus and A. Uonotus were also
present.

San Miguel de Sarapiqtii, Alajuela Province. — The small study
area was in rain forest at the edge of a swift mountain stream.
Parts of the area were flooded in times of high water, and masses

COSTA RICAN ANGLES
Table 1. — Study Areas and Angle Species Occurring on Them.

CO

CO

5

2
•2

Co

_co

en

s.

2

2
c

CO

CO

1

2

0

s
0

s

0
■g

S"
S

Si.

•2
'0

2
S

_co
1

0
0

3

CARIBBEAN HUMID

Finca La Selva . ^

X

X

X

X

X

X

X

?

Be\erly

?

?

X

X

?

X

?

Linion

X

Turrialba

X

X

X

X

X

X

X

?

San Miguel de

Sarapiqui

?

X

X

•J

X

X

V

X

PACIFIC SEASONALLY DRY

Playas del Coco ____

X

?

X

Sardinal

X

p

X

Rio Coiobici and

Rio Sandillal

X

?

?

Rio Congo and Rio

Abangares

X

X

X

Boca de Barranca ..

X

X

X

Quepos

X

X

Dominical

X

X

MONTANE

Monte\'erde . .

X

X

X

X

X

X

X

X

Hacienda El Prado

and Vara Blanca ..

X

X

?

San Jose-Cartago __

X

X

La Cruces

X

?

?

X

of drift were prominent features of the terrain. There were under-
cut banks, areas of bare rock and cobble, large trees, and dense,
luxuriant undergrowth. AnoUs luimilis was common. A. limifrons
and A. lionotus were moderately common, A. capito was found on
several occasions, and one individual of A. scriceiis was fovmd.

SEASONALLY DRY LOWLANDS OF GUANACASTE AND
NORTHERN PUNTARENAS PROVINCE

Playas del Coco, Giianacaste Province. — Thorny, xeric, decid-
uous woodland predominated, with some evergreen trees in ravines
and in altered situations near buildings. In 1965 Anolis cupreus
was found along cut banks of a ravine in woodland where there
were partly undermined trees with exposed roots pro\ading hiding
places. In 1967-196<S the lizards could not be found in this ravine
but were present in small numbers in a seaside lot with a stand of
thick brush and with some large trees. By 1970 they had become
moderately common in this lot. A. sericetis was found in smaller
numbers nearby on fence posts at the edge of a pasture in more
open terrain.

8 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

Sardinal, Guanacaste Province. — A relict strip of evergreen for-
est along a ravine provided habitat for anoles that were absent from
much more extensive areas of cultivated land and pasture. Giant
trees with buttressed roots, some undermined by erosion, heavy leaf
litter, and underbrush were features of the habitat that provided
shelter for anoles, mainly Atiolis cupreus. A. sericeus was found in
relatively small numbers and in more open situations, along wood-
land edge.

Rio Corobici, Finca La Pacifica, Guanacaste Province. — On the
south side of the river, forest consisting partly of evergreen trees,
some of giant size, with dense undergrowth, and with thick leaf
litter in places, provided habitat for Anolis cupreus, the only spe-
cies found. Rio Sandillal, a smaller stream several km farther south,
had somewhat similar habitat, but with less arborescent vegetation
and undergrowth.

Rio Congo and Rio Abangares near La Irma, Guanacaste Prov-
ince.— These two localities were separated by about 2 km of open,
dry, rolling terrain, where apparently anoles did not occur. Favor-
able habitat features near the streams were mixed groves of giant
evergreen trees, leaf litter, masses of debris with logs, sticks and
leaves left in high water and thick undergrowth. Anolis cupreus
was usually found associated with leaf litter near large trees, often
on their bases. A. pentaprion and A. sericeus were much less com-
mon and were found on trees but sometimes in relatively dry and
open situations marginal to the riparian groves. These were average
differences and all three species were closely associated.

Boca de Barranca, Puntarenas Province. — On the north side of
the Rio Barranca a resort village with many buildings, scattered
trees, including a variety of non-native species, and gardens with
ornamental herbs and shrubs provided an artificial habitat; Anolis
pentaprion was fairly common in trees but was difficult to find or
capture. A. sericeus was present in small numbers in trees and on
fence posts, but A. cupreus was absent. On the south side of the
river, in a more natural situation, with steep hillsides, and with
thorny xeric vegetation extending down to tidewater, A. cupreus
was common.

Quepos, Puntarenas Province. — Varied habitats near the town
included plantations of coconut and banana on the upper part of
the beach dune, mangrove swamps, wooded hillsides, pastures and
inland plantations, and dense forest. Both Anolis cupreus and A.
limifrons were found at woodland edge, in open woodland and in
plantation groves. A. cupreus was found on coconut palms near the
beach, and A. pentaprion was found on small trees in the town, on
the beach and in open woodland.

Dominical, Puntarenas Province. — Pastureland, plantations of
banana and cacao, scrubby woodland, and rocky and sandy beach

COSTA RICAN ANGLES 9

made up some of the main types of habitat at this locahty. Anoles
were generally absent from the more disturbed and altered habitats.
Both Anolis cupreus and A. limifrons were common in a cacao
grove, but A. cupreus was more abundant. Outside the cacao grove
they were much scarcer, and were found among trees and bushes
in low-lying land near the beach.

MONTANE EVERGREEN FORESTS OR FOREST REMNANTS

Monteverde, Puntarenas Province. — This locality was chosen to
represent montane evergreen forest, but was highly diversified be-
cause of the steep slopes, the rapid change with altitude and slope
exposure, and different amounts of disturbance and alteration by
human activity. The records of anoles obtained were scattered over
an area about 3 km across, extending from the continental divide
on the north almost to the floor of the San Luis Valley on the south.
All stations were along the headwaters of the Rio Guacimal and
its tributaries. At the lower elevations, the land was mostly open
pasture with scattered deciduous trees on the slopes and evergreens
along the streams, but at higher elevations there was cloud forest.
The settlement of Monteverde includes a general store, sawmill,
landing strip for aircraft, cheese factory, school, and about two
dozen dwellings, all well-scattered, but connected by road and by
a system of trails. Within the settlement, cleared pasture areas with
scattered trees alternated with blocks of forest. Relatively small
areas were devoted to cultivation. One such area was a grove of
banana and coffee trees surrounded by forest, where Anolis humilis
was common and A. intermedins was also present. Altitude ranged
from a little more than 500 m in the San Luis \^alley to more than
1700 m on the continental di\Tde. The settlement of Monteverde
extends over a considerable portion of this altitudinal range, and
the lower edge of the settlement is somewhat xeric in aspect with
much higher mean temperature than the upper edge. The latter is
essentially cloud forest.

Hacienda El Prado, AJajuela Province. — This area situated at
the continental divide, is in pastureland with scattered trees re-
maining from the original cloud forest. Trees, stimips and logs
support a luxuriant growth of epiphytes, and there is thick ground
cover of grass and herbaceous vegetation. Anolis intermedins was
found on fence posts, tree trunks and stumps. A. tropidolepis was
present in much larger numbers, nearly always among dense epi-
phytes, rarely on the ground. Habitat was similar at Vara Blanca.

San Jose, San Jose Province. — Many vacant lots in the eastern
part of the city, in the Los Yoscs, and Dos Pinos districts and along
the right of way of Ferrocarril de Costa Rica for several hundred
meters west of the Lhiiversity campus were found to provide favor-
able habitat for anoles, both Anolis cupreus and A. intermedins.

10 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

The lizards lived on trees and bushes, on walls, especially where
the bases were screened in a stand of tall grass, in coffee groves
(especially at their edges), and along fences that had living trees
as posts, especially where tall grass and herbs provided concealment
at lower levels.

Cartago, Cartago Province. — At this locality, 13 km airline from
San Jose, but in a cooler and dryer climate, both Anolis cupreus
and A. intermedins were found on fence posts at the edges of vacant
lots and pastures, in habitat similar to that at San Jose. A. inter-
medins, but not A. cnprens, was present throughout the intervening
higher area including the continental divide.

Las Crtices, near San Vito, Pnntarenas Province. — The field sta-
tion, administrated by the Organization for Tropical Studies, is in
mountainous terrain, and includes a canvon with a sizable stream
and numerous tributaries, partly in primary forest, but also with
cleared pastureland, coffee groves, and an arboretum, with exten-
sive gardens and lawns kept trimmed and watered. Only two spe-
cies of anoles were common on the area. Anolis polylepis was found
mainly in the arboretum and on planted trees and bushes near the
headquarters buildings; A. aqnaticus was in forest in rocky areas
along the streams.

My field work at Dominical was limited to a few days in March
1973. At Las Cruces near San Vito, field work was done in Feb-
ruary 1973 and February 1974. The study areas at Monteverde,
Rio Corobici, Rio Abangares, Rio Sandillal, and Finca La Selva
were each visited periodically at intervals of four or five weeks
throughout 1973 and in January and February 1974. The remaining
localities were visited mainly in 1968, and in February-March and
August-September of 1969 and 1970. Study areas at these latter
localities have been described in detail (Fitch 1973a).

Accounts of Species

In the following accounts of species, the 17 anoles studied are
considered separately, in order according to the amount of infor-
mation available for each kind. For each the description is brief
and is limited to characters that are considered to have ecological
significance and have not been thoroughly discussed in earlier liter-
ature— adult size, sexual dimorphism, color pattern and its poly-
morphism, and dewlap. More detailed descriptions of color, pattern,
lepidosis and bodily proportions may be found in Peters and Donoso-
Rarros (1970) for all species except Anolis carpenteri, Taylor (1956)
for all species except A. carpenteri and A. sericeus, Fitch (1973a)
for A. cupreus, A. humilis, A. intermedins, A. limifrons, A. lionotus,
A. tropidolepis and A. sericeus. Fitch (1972) for A. tropidolepis and
Echelle, Echelle and Fitch (1971a) for A. carpenteri. Also for each

COSTA RICAN ANGLES 11

species, habitat, including habitat preferences and "structural habi-
tat" (heights and diameters of perches), temperature, reproductive
cycle, and interactions (both interspecific and intraspecific) are
discussed insofar as information is available.

Anolis limifrons Cope
PI. I

Description. — This is a small, slender, dull-colored species with
long limbs and tail (Pi. I). Adults vary from 32 to 45 mm (SVL),
with means of 37.12 in 168 males and 38.37 in 145 females. Weights
vary from 0.6 to 1.7 grams and average 0.85 in 65 males and 1.11
in 54 females. The dewlap is small, dull white with a yellow cen-
ter, and averages 72 mm- in males of average size. The female
lacks a dewlap, averages 105.0% of male length and 130.5% of male
weight. The female is polymorphic with tlie following types of
pattern: (1) male type with dull olive dorsal color and a series of
middorsal black dots; (2) banded with a pale (cream-colored,
yellow, or pinkish) middorsal longitudinal area with or without
black edges, which, if present, may be either wide or narrow; (3)
having a series of diamond-shaped middorsal markings.

Ha])itat and behavior. — A. limifrons, the most ubiquitous Costa
Rican anole, is absent only at high altitudes and in the relatively
dry northwestern part of the country. It prefers a warm, wet cli-
mate and is more abundant in disturbed serai situations than in
forest climax.

Habitats where A. limifrons was found, in order of decreasing
preference, were: (1) Planted groves, with trees small or medium-
sized (less than 0.5 m DBH) and with ground vegetation between
the trees trimmed or cut from time to time. Cacao groves, charac-
terized by almost closed canopy and thick leaf litter, supported the
highest populations, but plantations of coconuts and other palms,
banana, and coffee were also inhabited. (2) Forest edge, especially
where there was dense ground cover. (3) Primary rain forest.

Its activity is concentrated between tree trunk and ground. Sur-
faces on which it rests or moves are, in order of declining preference,
(1) vertically-inclined tree trunks (ranging in size from giant trees
of climax forest to small saplings, and including such treelike ob-
jects as fence posts), (2) lianas or stems of small woody or herba-
ceous plants, down to a size slightly less than the lizard's body
diameter, (3) leaf-litter of forest floor, (4) root buttresses of large
trees, (5) grass, usually near or beneath trees, and (6) rock, some-
times bare, but usually with a mantle of bryophytes.

Of 191 A. limifrons for which position was recorded, 87.4% were
above ground level. Mean height was 0.78 m. For 75 adult males
height averaged 0.99 m, females and juveniles were on the ground
more often, and also tended to use lower perches. These obser-

12 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

vations were made in mature cacao groves, so most of the anoles
were observed on cacao trunks, 0.10 to 0.25 m in diameter.

An individual flushed on the ground would nearly always run
directly to the nearest tree, which was seldom farther than one or
two meters, and would climb the trunk on the side opposite from
the disturbance. The lizard might climb only a few cm above
ground level, or it might climb to a height of more than 2 m, usually
stopping where it was well-screened by vines or epiphytes. On
many occasions an anole that had been flushed and had climbed
above the scene of disturbance pivoted abruptly and faced down-
ward before coming to rest with its legs far extended both anteriorly
and posteriorly, but hardly protruding from the stem, and with its
chin and tail pressed close to the stem in an effectively cryptic
crouching posture.

Temperature. — Body temperatures (°C) in 124 A. limifrons
were found to be concentrated in the range 23 to 28 averaging be-
tween 26 and 27. Ballinger et al. (1970) found an average temper-
ature of approximately 27.0 in Panama. In the Caribbean lowlands
where A. limifrons occurs, diurnal air temperatures remain within
a few degrees of 25 throughout the year. In active lizards, body
temperatures are usually slightly higher than air temperature, and
there is some tendency to bask in direct sunlight when it is available.

Reproductive cycle. — Reproduction in A. limifrons has been in-
vestigated by Sexton et al. (1971) in the Panama Canal Zone. They
found that in climates lacking a severe dry season reproduction
continues throughout the year, but with constantly changing level,
highest in the wettest part of the year and lowest in the driest part.
In areas where there was a severe dry season, reproduction ceased
at that time. At Beverly and Turrialba in Costa Rica, Fitch ( 1973a)
found marked change in the level of reproduction with trends that
were roughly parallel. From mid-March through July there was
steady increase in the rate of breeding, which remained at a high
level from August through October, but from December through
April it subsided to a much lower level.

Samples were obtained at Finca La Selva, representing the
months of February, March, April, May, June, July, August, Sep-
tember, and October 1973 and Febmary 1974. The samples indi-
cated reproduction below the average rate in January, February
and March, approximately doubled in April, May, and June, and
subsiding again from July through December. The samples in April,
May and July had the highest ratios of adults, more than 70% in
each sample, and percentages of partly grown young were highest
in September and October (Figure 2).

Young judged on the basis of size to be in their first month (15
to 24 mm S-V) constituted a part of each monthly sample, indi-
cating year-round breeding in the population at La Selva. These

COSTA RICAN ANGLES

13

FEB MAR APR MAY JUN JUL AUG SEP OCT FEB

Fig. 2. — Changing ratios of adult and ju\'enile Anolis limifrons at Finca la
Selva in 1973 and early 1974; in each monthly set of columns black shows
young of 16-24 mm SVL (first month?), heavy shading shows those of 25-29
(second month?), light shading shows those of 30-33 (third month?) and open
columns show those of 34-46 (adults and subadults).

young averaged 12.0!?, but varied from 4.9 to 22.0% in different
samples, and probably much of this variation was induced by small
sample size.

Interactions. — In July 1973 a series of field tests was made on
adults of both sexes in their supposed territories on cacao trees near
the station headquarters at Finca La Selva. In the poorly-lighted
and well-concealed situations where the lizards occurred, close
range observations were necessary. As a result the resident anole
usually seemed to have its response somewhat inhibited by the
presence of the observer, so that appropriate stimuli failed to elicit
display or aggression, or such behavior was delayed or interrupted.

Disregarding negative results or delayed or interrupted re-
sponses that seemed to be due to the observer's presence, the trend
of responses was as follows: Adult males, presented with another
individual of the species, responded promptly. The usual sequence
was display, rapid approach and repetition of display at close range,
followed by pursuit or attack. All introduced individuals, regard-
less of size or sex, attempted to escape and hide, with little or no
attempt at self-defense. Territorial aggression was elicited by re-
lease of an introduced individual at distances up to 2 m from the
resident male.

A mirror on the end of a rod about 1 m in length was presented
to several individuals in their natural surroundings. On some at-
tempts the lizard fled as the mirror was very gradually extended
toward it to within a few centimeters. On other occasions the lizard

14 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

crouched to conceal itself at first, but then, noticing its image, over-
came the initial fright and responded with aggression involving
repeated displays and occasional attempts to attack. Females did
not display or attack, whether the stimulus was the mirror image
or an introduced individual.

On several occasions groups of recently captured anolcs were
placed in a common container soon after capture, with the result
that several males simultaneously displayed and behaved aggres-
sively while others showed only apparent fear and subordination.
Pursuit and attack occurred occasionally, with the usual result that
the sudden movements panicked all individuals in the container
and there was a general scramble to escape, ending aggressive be-
havior temporarily.

Interactions between A. limifrons and other species syntopic
with it were not seen. Opportunities for interactions are best with
A. htimilis because one or both may be abundant where A. hnmilis
and A. limifrons occur together. In several tests individuals of A.
hiimilis were presented to A. limifrons in the same manner as de-
scribed above for conspecifics, but with strikingly different results.
The introduced lizards did not elicit aggressive behavior and were
totally ignored.

A. carpenteri is the species most like A. limifrons. The two are
so similar that either might be mistaken for the other in the field,
and this resemblance is almost certainly the reason that the wide-
ranging and fairly numerous A. carpenteri was overlooked until
1970. Although their respective ecologies are inadequately known,
it seems that the structural habitat and food habits of A. carpenteri
are within the normal range of the more euryecic A. limifrons. At
La Selva A. limifrons vastly outnumbered A. carpenteri and, judg-
ing from the abundance of A. limifrons in collections and the rarity
of A. carpenteri, tlie same disparity probably prevails over much of
the area of sympatry. Presuinably this disparity would result in
intensive selective pressure on A. carpenteri by A. limifrons, but the
reciprocal effect would be negligible. A. carpenteri is more special-
ized in habitat and behavior; compared with A. limifrons, it is less
active, more scansorial, more cryptic, and its main habitat is on
vertical surfaces that are mantled with bryophytes.

A. lemurinus usually occurs in association with A. limifrons but
is much more restricted in habitat. Competition between them
probably is limited, because A. lemurinus is a much larger species,
approximately four times the bulk of A. limifrons. Also, A. lemu-
rinus is much less active and more secretive and spends most of its
time in cavities or depressions low on the trunks of large trees,
where foliage of vines and other concealing vegetation provide
shelter. Because of the great difference in size the more abundant
A. limifrons could not be expected to compete with A. lemurinus,

COSTA RICAN ANGLES 15

except possibly with juveniles. Reciprocally, A. lemurimts probably
likewise offers little competition to A. limifrons because of its lesser
numbers.

A. lionotus, because of its much larger size and aquatic or ri-
parian habitat, probably competes but little with A. limifrons, al-
though the two are sympatric over much of their ranges. A. capita
and A. hiporcatus are giant anoles that may subsist on prey larger
than that which A. limifrons is capable of catching or swallowing,
but both these large species are potential predators on A. limifrons.
The small, abundant A. limifrons may prove to be an important part
of the diet in each case when the food habits of the two larse
species are better known.

On the Pacific Coast A. litnifrons was found associated with A.
cupreus at Quepos and Dominical, under conditions that suggested
a rather rigorous competitive relationsliip. A. cupreus is much
more xeric in its adaptations than A. limifrons, and the area of
sympatry comprises a small percentage of the range of either spe-
cies. At both Quepos and Dominical, the two species were limited
to certain areas and habitats and were absent from more extensive
intervening areas. Both kinds were found alone at some sites and
associated at others, and sometimes both were abundant. The area
of overlap is a coastal strip extending for at least 55 km from
Parrita on the northwest to Dominical on the southeast. Perhaps
there is a gradient in climate and habitat from conditions most
favorable to A. cupreus on the northwest to those most favorable to
A. limifrons on the southeast. Also, perhaps each species is to some
extent limiting to the other. In the area of sympatry with A. limi-
frons (subspecies hiscutiger), Anolis cupreus (subspecies spilo-
melas) is larger than in the remainder of its range. Size relation-
ships between the two species are complicated by the fact that in
A. cupreus males are markedly larger than females, but in A. limi-
frons females are slightly larger than males. Table 2 shows length

Table 2. — Mea.v Size Ratios of Anolis cupreus and Anolis limifrons.

Sympatric Samples^ Allopatric Samples-

o 6 ?5 S $ 25

Ratio of limifrons males
to cupreus

Length 1:L34 1:1.50 1:1.13 1:0.98

Weight 1:2.80 1:1.90 1:1.90 1:1.22

Ratio of limifrons females
to cupreus

Lengtli 1:1.28 1:1.10 1:1.19 1:0.94

Weight 1:2.14 1:1.45 1:1.43 1:1.02

^ Quepos, Puntarenas Province.

-A. cupreus: Guanacaste Province; A. limifrons: Beverly, Limon Province, and Turri-
alba, Cartago Province.

16 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

and weight ratios in sympatry at Quepos and in allopatry (A. c.
cupreus in Guanacaste Province and A. I. liniifions at Beverly,
Limon Province, and Turrialba, Cartago Province).

Although A. cupreus does not extend far into the range of A.
limifrons, it is replaced by A. polylepis, a species of similar size and
habits, in the lowlands of extreme southern Costa Rica. Size re-
lationships between A. limijrons and A. polylepis are similar to
those between A. limifrons and A. cupreus. I did not find the two
species in sympatry because I spent little time in the area where
they overlap.

At Quepos I found A. pentaprion with A. limifrons, and prob-
ably they occur together throughout much of lowland Costa Rica
except the dry northwest, where A. limifrons is absent. However,
A. pentaprion is approximately four times the bulk of A. limifrons,
is more arboreal, and lives in drier, more open, places. Therefore,
it seems unlikely that there is much competition, and Anolis pen-
taprion probably is not large enough to be a regular predator on
Anolis limijrons.

Anolis humilis Peters

Description. — This is a small, stubby-bodied, dark-colored spe-
cies with relatively short limbs and tail. Adults vary from 32 to 43
mm (SVL), with means at 36.7 in 155 males and 38.5 in 106 fe-
males. Weights varied from 0.6 to 1.7 grams, with averages at 0.96
in 28 males and 1.31 in 38 females. The dewlap is relatively large,
bright red with dark scales, with a yellow outer edge, and with an
area of approximately 100 mm- in males of average size. The fe-
male lacks a dewlap but has a trace of the bright dewlap color on
the chin and she averages 105% of male length and 137.0% of male
weight. Females are polymorphic, having the dorsal surface dull
brown with no conspicuous markings, or a series of interconnected
middorsal dark, rhombic marks, or a wide, straw-colored or whitish
middorsal band.

Habitat and behavior. — A. humilis, perhaps the most terrestrial
of Central American anoles, lives in leaf litter of the forest floor, in
primary rain forest, and in plantations, especially cacao. It prefers
a warm, wet climate but also occurs up to elevations of more than
1500 m, where climate is relatively cool. Although A. humilis
spends most of its time on the ground, it has some scansorial ten-
dency and often climbs on vertical or inclined surfaces near the
ground. These include root buttresses of large trees especially
where there are vines to provide concealment, bases of cacao and
other small trees and shrubs, logs and sticks lying on the ground or
leaning against other objects, and leaf surfaces such as those of
banana or Heliconia.

In 165 instances at La Selva when height of the anole was re-

COSTA RICAN ANGLES 17

corded, 92% were on the ground or within 0.2 m, 5% were between
0.3 and 0.7 m and 3% were 0.8 to 1.2 m.

When flushed, the anoles would most often run for distances
less than 3 m, and then would hide in leaf litter in a superficial
situation. On other occasions they would run to the base of a cacao
tree and crouch on the side opposite that of the disturber, or would
nm over root buttresses, pausing under screening vegetation. Espe-
cially in the niches and crannies where the lizards sought conceal-
ment they were not easily relocated after an escape dash, and they
tended to depend on such concealment, not making another dash
until threatened at close range.

Temperature. — Eighteen body temperatures (°C) from Beverly
and San Miguel de Sarapiqui ranged from 22 to 27 degrees — "re-
markably low for a tropical lizard and for an anole" (Fitch 1973a),
but understandably so because A. Jnnnilis is a non-basker, staying
in deep shade of the forest floor. In February 1974, ten body tem-
peratures were obtained at Monteverde, at air temperatures of only
16.5 to 18.5. Mean body temperature was 21.5 ± 1.42, near the
lower limit of voluntary activity recorded for lizards. The lizards
found in the field under these conditions were noticeably slower
than those at La Selva where they were nearly always several de-
grees warmer. However, the insect prey is similarly slowed by low
temperature. A. humilis was found to be fairly common in the cloud
forest at 1530 m, above Monteverde where the climate is notably
cool and wet. On the afternoon of 26 February 1974, two that were
active were captured in light rain at air temperatures of 15.5 and
14.7. A. humilis is eury thermic, capable of carrying on essential
activities over a wide range of temperatures below its preferendum.

Reproductive cycle. — In the annual breeding cycle at Beverly
and San Miguel de Sarapiqui "evidence of year-round breeding, but
with seasonally changing levels, was provided by the distribution
of hatchlings and other young. . . Numbers of hatchlings were
relatively low in most January to April samples, bearing out the
evidence from gravid females that the rate of reproduction is some-
what slackened during the early months of the calendar year"
(Fitch 1973a).

The data obtained subsequently from the somewhat different
habitats and climates of Finca La Selva and Monteverde conform
fairly well with the data from Beverly and San Miguel. Young in
the size range typical of the first month of life were present in each
monthly sample from both localities, and made up from 5% to 47.8%
(between 11% and 31% in most instances, averaging 21%). Table 3
shows the compositions of ten monthly samples from Finca La
Selva and seven from Monteverde. For the purpose of these calcu-
lations the following age-size (snout-^'ent) correlation was used.
First month, 14 to 20 mm; second month, 21 to 25; third month, 26

18

OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

Table 3. — Changing Composition of Populations in Anolis humilis from

FiNCA La Selva and Monteverde.

Percentage in Each Age Class^

First

Time and Place of Sample Month

FINCA La Selva

Feb 1973 22.1

Mar 1973 12.5

May 1973 25.5

Jim 1973 23.2

Jul 1973 26.5

Aug 1973 17.4

Sep 1973 47.8

Oct 1973 30.9

Feb 1974 18.5

Mar 1974 14.6

monteverde

Mar 1973 11.1

May 1973 11.1

Jul 1973 5.0

Aug 1973 20.8

Sep 1973 36.0

Feb 1974 13.6

Mar 1974 15.8

Second
Month

Third

Month

Adult

Number in
Sample

14.0

8.1

55.9

86

16.1

11.1

59.8

112

23.4

12.7

38.3

47

25.0

14.3

37.5

51

12.0

9.3

52.0

75

8.7

8.7

65.3

23

22.8

9.1

20.4

44

14.5

9.1

36.4

50

18.5

11.1

51.9

27

25.9

8.6

36.8

116

16.6

11.1

61.1

18

33.3

22.2

33.3

9

15.0

15.0

65.0

20

12.5

16.7

50.0

24

4.0

8.0

52.0

25

22.7

31.8

31.8

22

26.3

21.0

36.8

19

1 Age classes estimated on the basis of size, SVL.

to 29; adult, 30 to 42. These correlations are based upon growth
rates of marked individuals at Beverly and San Miguel (Fitch
1973a). However, some individuals that grew faster or slower than
usual may have been incorrectly allocated. Also, in the relatively
cool climate of Monteverde, growth rate is probably slower than
the rate measured at Beverly and San Miguel. Because the species
was relatively uncommon at Monteverde, the samples from there
averaged smaller, with only 20 lizards contrasted with an average
of 69 per sample at La Selva. The Monteverde samples are there-
fore much less reliable. Both series agree in having greatest num-
bers of first-month young in September (more than twice as many
as the average for the remainder of the year), and in having rela-
tively few small juveniles in February and March.

Interactioris. — On several occasions when an anole of this spe-
cies, startled by a field worker, made a short escape dash, it hap-
pened to approach a second individual, which responded with a
threat display, spreading its dewlap and bobbing. When several
adult males were put together in a small container, they displayed
vigorously at each other, and the displays were easily recorded on
film. Attempted field tests of aggression in adult males included
presentation of a mirror and presentation of a tethered individual
on the end of a pole; each was unsuccessful. The resident indi-

COSTA RICAN ANGLES 19

vidual invariably moved away, disturbed by the investigator and
by the movement, and did not return. Living in leaf litter on the
ground, individuals of A. humiJis seem to be less attached to spe-
cific points than are individuals of other species that habitually use
certain perches.

Interactions between A. humilis and other species were not seen.
Since A. humilis and A. limifrons are abundant in the same habitat,
interactions between them must be frequent and important to both.
However, differences in appearance and behavior are sufEcientlv
great that there is mutual indifference, and neither was observed to
respond directly to the other's presence, either in the field or in
confinement.

A. humilis was found associated with 11 other species and
probably overlaps still others. A. capita (La Selva, San Miguel),
A. biporcatus (La Selva, Turrialba), A. icoodi (Monteverde), and
A. insignis (Monteverde) are large arboreal species that may prey
on A. humilis. The relationship seems least likely or least important
for A. biporcatus, because it spends most of its time high in the
trees whereas A. humilis is on the ground or at the base of the trees.
A. lemurimis (La Selva) and A. lionotus (La Selva, San Miguel,
Turrialba, Monteverde) are large enough to be potential predators
on the young of A. humilis. Opportunity for such predation exists,
especially for A. lemurinus associated with A. humilis low on the
trunks of large trees. A, lionotus also has been found closely asso-
ciated with A. humilis, near the edge of the river at San Miguel.

A. sericeus (San Miguel) and A. carpenteri (La Selva, Turri-
alba, Beverly) are about the same size as Anolis humilis but are
much more arboreal. Where they occur together the competition
of the abundant, terrestrial Anolis humilis might exert selective
pressure for arboreality.

Anolis cupreus Hallowell
PI. II

Description. — In this medium-small, dark brown species, adults
vary from 32 to 49 mm (SVL), with means of 41.85 in 105 males
and 36.34 in 107 females. Weights vary from 0.70 to 2.20 grams,
and average 1.6 in 38 males and 1.13 in 37 females. The relatively
large, rounded dewlap extends to mid-body or slightly beyond; it
is pinkish rose with a dark amber-orange inner area, and averages
about 250 mm- in a typical male. The female lacks a dewlap but
may have a trace of pinkish color on the chin. The female averages
86.9% of male length and 71.0% of male weight. Females are poly-
morphic and may have a pale, middorsal band of variable wadth
and color — white, cream-colored, pink or orange, with or without
black edges — or may have a middorsal series of connected, dia-
mond-shaped middorsal marks or a series of middorsal chevrons;

20 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

or, lacking any of these patterns, they may be a nondescript brown.

Habitat and hchavior. — A. ciipreiis is mainly terrestrial but with
some scansorial tendencies. Its preferred habitat is leaf-litter be-
neath evergreen forest, which is usually limited to the vicinity of
stream courses in the seasonally dry region where it occurs. Occa-
sionally, the lizards may be found in dry deciduous or mixed forest.
They often utilize the bases of large trees, or may climb on stems
of small trees or bushes. They may live in grassland where there is
thick ground cover, with trees, bushes, or fence posts to climb.
High populations have been found along ravines with undercut
banks and exposed tree roots, which provide hiding places. Vari-
ation in habitats and population density have been described by
Fitch (1973c).

For 197 A. cupretis in Guanacaste, mostly at Rio Abangares,
height averaged 0.565 m (0.666 m in 139 adult males, exactly twice
the 0.333 m of 58 females). For a smaller series at San Jose, Fitch
(1973a) recorded a mean of 0.73 m for males (N^48) and 0.36 for
females (N^IO). At times the lizards were found on stems as
slender as 1 cm. At San Jose, where they were hunted along
fences, most were caught on posts, which averaged approximately
0.15 m. However, many were found on cement walls around vacant
lots, especially where there were vines, high weeds, or grass. In
Guanacaste the most comparable habitat niche included trunks and
root buttresses of giant trees.

Temperature.— Fitch (1973a, 1973c) and Clark (1973) have
discussed temperature relationships of A. ctipreus. The species is
eurythermic and has been found active with body temperature as
low as 18.8°G. In the relatively cool climate of the Meseta Central
it is usually found in open situations and is somewhat heliothermic,
but in the lowlands of Guanacaste it usually is limited to deep
shade, and body temperature approximates air temperature. For
these lowland lizards body temperatures were concentrated between
31 and 33.5. On the Meseta Central body temperatures were con-
sistently lower than they were in Guanacaste.

Reproductive cycle. — The general pattern is one of interrupted
reproduction for the duration of the dry season, from some time in
December to some time in April, then a peak in reproduction soon
after the start of the rainy season, with successive increments of
young to a population that consists at first essentially of adults.
Fitch (1973a, 1973b) found an annual schedule essentially like that
described above at Cartago, Cartago Province, San Jose, San Jose
Province, Boca de Barranca and Quepos, Puntarenas Province, and
Playas del Coco, Sardinal and La Irma, Guanacaste Province.

Samples obtained from Guanacaste, Rio Congo, Rio Abangares,
Rio Sandillal and Rio Corobici in 1973-1974 represented all months
except June, September, November and December, but the sum-

COSTA RICAN ANGLES 21

mer samples were small, with only 7 in May, 9 in July, and 6 in
August. In these samples hatchlings were absent from March
through July and other young were absent from March to October,
except for one of 30 mm in April and one of 25 mm in August. In
July and August the population consisted of adults and hatchlings,
with no individuals of intermediate size (except the one of 25 mm
in August). In October there were young of all sizes, indicating
that those hatched in July were approaching minimum adult size,
with steady increase in numbers of young meanwhile, from succes-
sive hatchings. In February 1973, all sizes of individuals also were
present, but with fewest hatchlings and progressively more indi-
viduals in the second-month, third-month, and fourth-month size
classes, suggesting tapering off of egg production from perhaps late
September or early October through November and December.
However, the January 1974 sample had only one first-month young
and none in the second-month or third-month classes, indicatins:
much less reproduction in autumn 1973 than in autumn 1972.

Interactions. — Intraspecific encounters, and ecological relation-
ships with the sympatric A. sericeus, A. pentaprion, A. lemurinus,
A. "hiscuti'^er" {= limifrons), A. intermedius, A. lionotus and the
extralimital A. dolJfusianus have been discussed by Fitch (1973a).
In instances of syntopy with A. sericeus, A. limifrons, and A. inter-
medins both A. cupreus and the associated species occurred in high
population densities with partitioning of resources. In each instance
A. cupreus was the larger and less arboreal species. A. pentaprion
is so much larger and so much more arboreal than A. cupreus that
little if any competition could be expected.

A. lionotus, because of its semi-aquatic habits and markedly
larger size probably does not have much direct competition with
A. cupreus either. To the extent that interaction does occur where
the two occur in adjacent areas, A. lionotus would be more affected
than A. cupreus, because the latter occurs in much higher popu-
lation density over a wider range of habitat conditions. Much of
the A. cupreus population is removed from contact with A. lionotus,
whereas all individuals of A. lionotus, being linearly distributed
along stream courses adjoining woodlands or thickets, are poten-
tially exposed to interaction with A. cupreus.

Where A. cupreus overlaps A. lemurinus, a somewhat similar
situation exists, the larger A. lemurinus being present in much
lower densities and restricted to a more specialized habitat niche
(in this case, bases of large trees). However, these two species are
largely if not entirely allopatric in Costa Rica. In southeastern
Guatemala, where they do overlap, A. lemurinus is much larger,
and character displacement seemingly has developed. A scries of
30 A. lemurinus from the southern parts of Chiapas, Mexico, and
Guatemala compared with the series from La Selva, were 16% larger

22

OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

in linear dimensions and 96% heavier. In allopatry A. ctipreus
(male) is 79% of A. lemurinus length and 48% of its weight. In
sympatry A. cupreiis is 74% of A. lemurinus length and 31% of its
weight. Instead of becoming smaller when allopatric to A. lemu-
rinus, A. cupreus actually becomes larger, increasing by about 9%
in length and 26% in weight. A plausible explanation is that in
Guatemala A. cupreus is affected less by A. lemurinus than by the
smaller A. sericeus, which is abundant and similar to Anolis cupreus
in habits.

Instability of local populations. — A. cupreus commonly attains
population densities of 2500 to 5000 per hectare. Each of the local
populations studied was present in some such numbers, but in every
instance the population proved to be unstable and within a few
months underwent such drastic reduction that none could be found
on the original study areas, or there were too few for a population
sample (Table 4). The first few examples of population crashes
that were observed were in urbanized areas of San Jose, and were
tentatively attributed to use of insecticides, but this explanation

Table 4. — Evidence of Population Crashes in Anolis cupreus.

Place

Time of observed abundance Time of observed scarcity

or absence

1. — N Guanacaste, ravine E

Playas del Coco
2. — N Guanacaste, ravine W

Sardinal
3. — S Guanacaste, Rio Corobici

at Finca La Pacifica

4. — S Guanacaste, Rio Sandillal

along Highway #1 near

Las Cafias
5. — S Guanacaste, Rio z\liangares

at Highway #1
6. — S Guanacaste, Rio Congo

1 km E La Inn a
7. — Pimtarenas, Boca de Barranca

cliff, S side of river mouth

8. — San Jose, along railroad W
Universidad de Costa Rica

9. — San Jose, lot at Eldorado

Apts.
10. — San Jose, lot at Calle 29,

Ave. Central
11.— San Jose, lot at Calle 27,

Ave. 10

March 1965

Oct. 1967 through Mar. 1970

26 mo., Ian. 1968 to Feb. Feb. 1973

1970

1972 according to verbal Oct. 1967 through July 1968

accounts of several Feb. 1973 through Mar. 1974

observers

early 1974 July 1974

3 mo., Feb., Mar., Apr.

1973
6 mo., Jan. through Jun.

1968
18 mo., Jan. through

Aug."l968
Jun. 1969
6 mo., Nov. 1967 through

Apr. 1968

6 mo., Jan. through

May 1968
15 mo., Jan. 1968

through Mar. 1969
17 mo.. May through

Aug. 1968, Jan. through

Aug. 1969 "

June 1973 to Mar. 1974

July 1968 through Mar. 1970
Feb. 1973 through Mar. 1974
Aug. 1969

Jul., Aug. 1968; Jan. to Mar.,

Aug. 1969
Jan., Feb. 1970
Tun., Jul., Aug. 1968; Feb. to

Aug. 1969; Jan., Feb. 1970
Jan. through Mar. 1970

Jan. through Mar. 1970

COSTA RICAN ANGLES 23

certainly does not apply to all observed instances, and perhaps not
to any.

No population was under intensive observation during the pe-
riod of reduction, and it is therefore not definitely known just how
reductions occurred. At Rio Congo, the low, flat, study area, almost
enclosed in loops of the river, was flooded in May or early June
1968 and the anoles there were nearly all drowned or swept down-
stream. Only a few indi\'iduals remained on the 0.057 ha study
area, but they were still fairly abundant in nearby areas not flooded.
By February 1969 the original study area again was populated, with
anoles in perhaps 15% or 20% of their former abundance, but in
August 1969 and February 1970 they were absent or at an extremely
low level. From February 1973 through March 1974, also, they
were absent or very scarce on the original study area but were
present in low density in a grove 100-200 m downstream.

Under favorable conditions rapid increase may occur, since a
female is capable of producing eggs at 10-day intervals (Fitch
1973a). When high densities are attained, density-dependent mor-
tality factors perhaps come into play. Probably predation by birds
and snakes is important in some instances.

Anolis intermedius Peters
Pkll

Description. — In this small, pale olive or ashy colored species,
limbs are relativelv short, the tail is short and blunt-ended and
adults vary from 38 to 52 mm (SVL) with little if any difference
between the sexes ( mean S\^L 45.8 =!= 0.36 mm in 94 males and
45.4 ± 0.64 in 34 females; 1.84 ± 0.57 g in 37 males, 1.825 ± 0.885
in 19 females). The dewlap is medium-sized, dull white, about 110
mm- in the male, but lacking in the female. Males may have sev-
eral broad, dark pale-edged transverse bands or blotches on the
body or may have irregular, small black marks. Females may have
color and markings like those of the male or may have a broad,
middorsal stripe, cream-colored or orange, sometimes edged with
black.

Habitat and behavior. — A. intermedius is arboreal, usually
climbing on trunks of relatively small trees. It may climb into the
canopy and mo\'e about on small twigs or foliage. It is cryptic in
color and behavior, less active than many other species. A high
proportion of those found were on fence posts. Trees and posts of
about 0.15 m in diameter were preferred.

For a composite sample of 106 A. intermedius height averaged
1.25 m (1.32 for 86 males, 0.975 for 20 females). The four lowest
individuals, including one at ground level, were all females. For
the sample of 75 at Monteverde, average height of 1.27 m was not
significantly different from that of 31 from San Jose, 1.22 m, al-

24 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

though at San Jose A. intermedhis occurred syntopically with the
more abundant and less arboreal A. ciipreus.

Temperature. — In 18 adults at Monteverde in February 1974
body temperature (°C) ranged from 19.1 to 28.8 and averaged
23.2 ± 0.575. Air temperature averaged 17.3 — 5.75 below body
temperature. In each instance air temperature was lower than body
temperature, but the difference varied from 1.6 to 10.6. Half the
body temperatures were in the two-degree range 22.3 to 24.2, sug-
gesting a preferendum at about that le\^el.

With a much larger series of records from San Jose, Fitch ( 1973a)
found body temperatures ranging from 17.4 to 33.7 but concen-
trated between 25 and 28. Clark (1973) studied A, intermedhis at
Ciudad Universitaria near San Jose. Thirteen body temperatm-es
obtained while the sky was clear averaged 27.3 ± 0.7 (23.6-31.0).
The trend of lower body temperatures at the higher altitude of
Monteverde (1380 m) as compared with San Jose (1197 m) and
the wide range of temperatures in the active lizards indicates that
the species is relatively eurythermal and does not have a well de-
fined preferendum.

At Hacienda El Prado, 1910 m, Fitch (1972) obtained 15 body
temperatures which ranged from 17.4 to 30.7 and averaged 23.6,
5.8 above air temperature. Trend was thus similar to that at Monte-
verde although Hacienda El Prado is 530 m higher and has a
cooler climate.

Reproductive cycle. — The population samples obtained at Mon-
teverde in March, April, May, July, August, September 1973,
and Februaiy 1974 were mostly too small to show the full range of
age groups that might have been present. The samples in March
(24), April (27), and May (14) were all adults; their sex ratios,
( ^ : 9 ) were, respectively 24:0, 20:7, 11:3. The July sample had
one second-month juvenile (27 mm), most probably representing
egg-laying in early April. The September sample had young of 25,
29, 31, 32, 34, 37, and 38 mm, believed to represent egg-laying
from April through June. Only three of the 13 anoles in the Sep-
tember sample were fully adult. The February 1974 sample con-
sisted mostly of adults, but had individuals of 25, 35, 37, 39 and 39
mm, believed to represent egg-laying from early September through
early November. These combined records indicate a reproductive
season extending from early April into November, and no repro-
duction from December through March, the drier part of the year.
These findings are essentially in agreement with conclusions based
on more extensive data from San Jose, at lower elevation in a some-
what warmer and drier climate (Fitch 1973a, 1973b).

Interactions. — On various occasions adult males were seen to
display toward each other in the field, and ordinarily there was only
one male to any tree trunk or fence post, indicating mutually ex-

COSTA RICAN ANGLES 25

elusive territories. Where the highest concentrations of the anoles
were found, there were many within a few square meters, but these
were places where there were spiny bushes and small trees with
many trunks or stems on each square meter of ground surface, and
the lizards may have had small three-dimensional territories. When
several adult males were confined together, they displayed vigor-
ously with occasional pursuit or brief combat.

At Monteverdc where most of my observations were made, A.
intermedhis was found in association with four other species and
in proximity to two additional kinds. In a small plantation of
banana and coffee trees where A. humilis was abundant, A. inter-
medins was also present. In this syntopic situation A. intermedins
was noticeably the more scansorial. Both in geographic ranges and
in habitats the t^vo are mainly distinct, and the overlapping that
occurs could not represent much selective pressure on either.

At Monteverde also, A. intermedins was found several times in
the same trees with A. icoodi, or in nearby trees, but no actual
interactions were observed. The range of A. icoodi may be mostly
within that of A. intermedins, but A. icoodi is, on the average, on
larger trees and is in deep shade, whereas A. intermedins frequents
relatively open situations. Because of these differences, and be-
cause A. icoodi is 5.5 times the bulk of A. intermedins, there is
probably little or no competition between them for most sorts of
resources. At higher altitudes east of Monteverde, A. intermedins
and A. tropidolepis were found in proximity. At Hacienda El Prado
they were found on the same tree trunks, logs and stumps. Even in
this overlapping habitat they were partly separated; A. tropidolepis
was usually among dense epiphytes, whereas A. intermedins fre-
quented open surfaces and basked in sunshine at every opportunity,
maintaining an average body temperature more than four degrees
higher than that of A. tropidolepis.

A. insignis was found only a few times but one juvenile was
found within 3 m of an adult male A. intermedins of approxi-
mately equal size. When confined with several A. intermedins this
juvenile displayed vigorously in response to their displays. Ordi-
narily A. insignis is higher in the trees than is A. intermedins; it
may prey on A. intermedins.

A. lionotns and A. intermedins are widely sympatric, but A.
lionotns, as a semi-aquatic streamside species, probably does not
often interact with the arboreal A. intermedins. A. sericens is sim-
ilar to A. intermedins in size and in arboreal tendencies, but is a
far more slender and active species, and occurs in more xeric situ-
ations. Although I found both kinds at Monteverde, they probably
do not overlap here, but are complementary in distribution, A.
sericens at lower altitude in hotter more xeric habitat. At Monte-
verde A. intermedins and A. cnprens did not overlap, but seemed

26 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

to be altitudinally separated by a fairly wide zone where neither
was present. However, in the vicinity of San Jose they were found
syntopically at many places. At some places both were abundant
but usually A. ctipreus was the more numerous. Broad overlap in
structural niche was indicated, with A. intermedins averaging higher
and ". . . there was partial segregation with A. intennedius on the
bases of large trees and A. cupreus on small trees and shrubs"
(1973c).

Anolis carpenteri Echelle, Echelle and Fitch

Description. — This is a small, slender, pale green anole of 35 to
45 mm SVL (mean, 38.5 in six males and 40.4 in 14 females).
Weights vary at least from 0.65 to 1.20 grams averaged 0.704 in
five males and 1.00 in nine females. The dewlap is bright orange
and approximately 150 mm- in males of average size. The female
lacks a dewlap but may have a trace of the orange color on the
chin. The female averages 105.0% of male length and 1.42% of male
weight; other external sexual differences are minor. The female
may have faint X-shaped dorsal body markings that are lacking in
the male.

Habitat and behavior. — The series of 10 A. carpenteri on which
the original description was based were all found in the riparian
zone of lichen-covered rocks and tree trunks underwater in times
of Hood, along the Rio Reventazon 7 km ESE Turrialba (Echelle,
Echelle and Fitch 1971a). In field work at Finca La Selva, only 14
additional records were obtained, but none of these was in a ri-
parian habitat; five were in relatively undisturbed rain forest, six
were in cacao groves and three were in an arboretum or a palm
plantation, where there were trees of various sizes, well spaced,
with undergrowth and ground vegetation cleared at intervals. Aver-
age height of lizards above ground was 0.56 ± 0.17 m (0.76 for five
males and 0.44 for nine females ) . Five lizards were at ground level,
three of them at the bases of trees, and two in leaf litter. The
trunks used ranged in size from those of giant forest trees down to
stems approximately the diameter of the lizards' bodies. In every
instance the anole was on or near a lichen-mantled tree trunk or
log which provided a concealing background. Compared with other
similar small species, A. carpenteri is less swift and agile, and de-
pends to a greater extent on cryptic coloration and behavior for
safety. Of the 14 recorded, two on tree trunks and one on a log
dropped to the ground almost immediately after being flushed.

Temperature. — No body temperatures were obtained from A.
carpenteri. Mean body temperature could be expected to approxi-
mate 27°C, as it does in A. limifrons found in the same situations.
Both ordinarily are non-baskers and approximate ambient tem-
peratures.

COSTA RICAN ANGLES 27

Reproductive cycle. — Females examined at Finca La Selva in
February, April. August, October and November appeared to be
carr^ang eggs and there is probably year-round breeding in A. car-
penteri at this localit)% but too few records are available to indicate
whether the level changes during the year. Only two of the 14 A.
carpenteri examined were below adult size (both 32 mm SVL).
From analogy with A. limifwns, these two were judged to be about
three months old when they were recorded, in mid-November and
late February, respectively. Breeding in early July and in October
is indicated. The type series of ten A. carpenteri from near Tur-
rialba in early March consisted of adults, except for one of 32 and
one of 28 mm, which may represent breeding in October and No-
vember. It is remarkable that no smaller young are represented in
the capture of 24 A. carpenteri. The cryptic coloration and behavior
of A. carpenteri may make the young especially difficult to find, or,
if the species has a higher survivorship than other small species, the
reproductive potential may be correspondingly low, with few young.

Interactions. — Because of their low population density individ-
uals of A. carpenteri were not seen to interact in the field. The five
males and five females on which the original description was based
were all collected on the same afternoon and were confined together
before preservation, and the males displayed vigorously.

Of the six other species found with A. carpenteri at Finca La
Selva, only A. Umifrons could be a severe competitor. Resource
utilization by A. carpenteri seems to be entirely within that of the
similar-sized but much more numerous A. Umifrons; presumably A.
carpenteri is able to exist by efficient utilization of resources that
are somewhat marginal to A. Umifrons. At Turrialba, where the
original series of ten A. carpenteri was collected in about an hour,
the lizards were well segregated from A. Umifrons on the relatively
open surfaces of water-swept riparian rocks and tree trunks below
high water mark, whereas A. Umifrons was farther up on the bank
in dense vegetation and in a variety of other habitats not associated
with water. At Finca La Selva it took 10 months of field work to
obtain an equal number of records, and segregation was not clear-
cut. However, there too A. carpenteri was found mainly on ex-
posed, lichen-covered surfaces, whereas A. Umifrons tended to be
in or near situations where there was screening foliage. Although
both were found on the ground in some instances, A. carpenteri
seemed definitely more arboreal.

A. hiimiUs is the only other syntopic species of approximately
the same size as A. carpenteri; as mentioned under the account of
A. humiUs, there is vertical stratification with little overlap, and any
competitive relation that may exist is one-sided because of the much
greater abundance of A. hiimiUs.

A. lemuriniis is comparable to A. carpenteri in degree of arbo-

28 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

reality but it is largely restricted to trunks of large trees and tends
to seek cavities or depressions that are screened by vegetation,
whereas A. carpenteri frequents exposed surfaces. Furthermore A.
lemurintis is approximately four times the bulk of A. carpenteri.
A. liotiotiis is even larger, and being closely confined to streamside
habitat it would liave little opportunity to interact with A. carpen-
teri. A. hiporcatus and A. capita are large and relatively uncommon
arboreal species which might prey on A. carpenteri occasionally, but
otherwise would have little or no interaction with it.

Anolis tropidolepis Boulenger

Description. — In this medium-sized, short-headed, long-legged,
dark colored species, adults vary from 42 to 59 mm, mean 50.6 in
167 males and 50.3 in 98 females. Weights vary from 2.0 to 4.3
grams, average 3.14 in 21 males and 3.32 in 13 females. The dewlap
is relatively small, variable in color from dark red to reddish orange,
and averages about 160 mm- in males of average size. The female
has only a trace of a dewlap, with some reddish coloring of the
chin. Females are polymorphic, having a cream-colored, mid-dorsal
longitudinal band with varying amounts of black along its edges, or
having a series of diamond-shaped mid-dorsal marks, or having a
male type pattern, with a series of more or less V-shaped mid-dorsal
spots, or pairs of spots.

Habitat. — A. tropidolepis is limited to cloud forest, and lives on
trunks or root buttresses of trees, logs and stumps supporting a
dense growth of epiphytes, both woody and herbaceous. Most of
those found were between ground level and 2 m. Some have been
found on the ground, in brush piles or in grass and others in trees
up to a height of 10 m (Fitch, 1972, 1973a).

Temperature. — A. tropidolepis is adapted to a cool climate, is a
nonbasker, and is active over a wide temperature range. Most of
those found active were at air temperatures of 14-20°C, and body
temperatures were almost evenly distributed from 15 to 24, with a
few above or below these limits. For 286 body temperatures of
active lizards mean was 19.5 ± 0.15 — remarkably low for any lizard.

Reproductive cycle. — In the study at Hacienda El Prado evi-
dence was obtained that females require approximately 9 months
to reach sexual maturity, and thereafter produce eggs one at a time
at approximately monthly intervals with little or no seasonal vari-
ation ( Fitch, 1973a ) .

Interactions. — Because they live in dense cover and in medium
or low population densities, these anoles have not been seen to
interact under natural conditions. In confinement they are excep-
tionally aggressive. Males placed together display vigorously and
then fight, biting each other sometimes witli prolonged retention of
grasp as the contestants lie interlocked. Females seemed almost as

COSTA RICAN ANGLES 29

aggressive as males and heterosexual fights were observed.

A. tropidolepis being more tolerant of low temperature than any
of the other species that were observed, lives at higher altitudes on
the average, but it overlaps A. intermedins, A. humilis, A. tcoodi,
and A. lionotus to varying degrees. Syntopy with A. intermedins is
discussed under the heading of that species. Overlap with A. hii-
miUs is slight and even within the zone of overlapping the two are
largely segregated, A. humilis to leaf litter and A. tropidolepis to
epiphyte-covered tree trunks. Overlap with A. lionotus may be
fairly extensive but segregation is sharp here also, with A. lionotus
in open streamside situations and A. tropidolepis on epiphyte cov-
ered tree trunks. Overlap with A. woodi is slight and interaction
between the two is further reduced by difference in microhabitat
requirements, although both live on tree trunks. A. ivoodi was al-
ways on bark that was bare or had only a superficial layer of lichens,
while A. tropidolepis was always in dense epiphytic growth.

Anolis woodi Dunn

Description. — This large, extremely slender, dark, dull colored,
blue-eyed species has long slender legs and an attenuate tail. Adults
of the population studied vary from 74 to 95 mm SVL (mean 84.5
± 1.62 in 24 males and 80.6 ± 1.02 in 18 females). Weights vary
from 6.7 to 16.8 grams and average 10.7 in 19 males and 10.9 in 12
females. The dewlap is large, dark olive brown with scales dull
white, and in two adult males was 782 and 795 mm-, but in females
it is smaller, only 11% of the male's area. There are several faint
dusky transverse dorsal bands on the body, which is slaty with a
greenish sheen and with scattered salmon patches both dorsally and
ventrally. Except for the dewlap the sexes are not noticeably dif-
ferent in color or markings. Females averaged 95.4% of male length
and 102.0% of male weight in the small series available, but these
differences were not statistically significant.

Habitat and behavior. — A. tcoodi is scansorial on tree trunks in
submontane evergreen forest. For 49 records the height ranged
from ground level up to 4.5 m ( mean for 29 male records 2.06 ±
0.16 m, for 20 female records 1.52 ± 0.264 m). Most of these anoles
were on non-native cypress trees (Cupresstis sp.) planted along the
edge of the main road in a row, discontinuously for about 1 km.
Trees on which the lizards were found were mostly 0.2 to 0.5 m in
diameter. The bark surface was rough, with small flakes and ver-
tical cracks, dark brown, either bare or with a thin layer of lichen.
The anoles were cryptic in appearance and behavior. Before being
seen they probably were aware of the approach of a human, and
were alwavs flattened against the tree trunk, so well concealed tliat
they would have been unnoticed by a casual passerby. Unlike other
kinds of anoles, they did not reveal their presence by an escape

30 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

COSTA RICAN ANGLES

31

Plate II. Upper: Adult male Anolis intermedins, San Jose, March 1975.
Middle: Subadult male Anolis cupreus, San Jose, March 1975. Lower: Adult
female Anolis cristatellus, Limon, March 1975.

Plate I. Upper: Adult male Anolis pcntapiion, Quepos, March 1970.
Middle: Adult male Anolis limifrons, Quepos, March 1970. Lower: Base of
large tree with lianas and epiph>tes, Finca La Scha, February 1973; habitat
for Anolis limifrons, Anolis Jiumilis, Anolis lemurinus and Anolis capito.

32 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

dash, but "froze." The crouching lizard was not always entirely
motionless, but might, with almost imperceptibly slow creeping,
edge out of sight around the tree trunk. On various occasions the
individuals that were observed on tree trunks were revisited later
on the same day, and were sometimes found in almost the same
position after several hours. If they had moved more than a few
centimeters they usually could not be found. The cypress trees had
dense crowns and the trunks where the lizards were found were
usually in deep shade. At times when sunshine fell on the trunks,
early and late in the day, the lizards found were on the shaded sides.

Temperature. — Only one body temperature was obtained,
21.5°C, and in this instance the anole was on the ground, an atypi-
cal situation, and was three degrees warmer than ambient air tem-
perature. In 29 instances when air temperature was recorded in
the general area where the anoles were found, it ranged from 15.5
to 1(8.5, mean 17.9. In anoles clinging to tree trunks, body temper-
ature could be expected to approximate air temperature, which by
day was often in the range of 16.5 to 18.5 degrees.

At different times several individuals of A. ivoodi were captured
and temporarily confined for observation or photographing. Soon
after capture some of these individuals seemed to go into shock, or
died suddenly and unexpectedly. Aside from stress of capture in
these seemingly phlegmatic lizards, the only obvious explanation
was that overheating by brief contact with the collector's hand, or
exposure to sunshine or to air temperature a few degrees above
normal was injurious.

Reproductive cycle. — Females that appeared to be gravid were
processed on 9 July, 13, 16, and 19 August, 29 September, 29, 30,
and 31 October and 11 March; year-round breeding is suggested
but not definitely established by these records. The smallest indi-
vidual of A. woocli, of 31 mm (SVL) was found on 25 October, and
was judged to be a hatchling from its size ratio to adults and
analogy with other species. Another juvenile of 48 mm was re-
corded on 14 August. Other immatures recorded were all in the
size range 55 to 65 mm ( SVX ) 25 October, 5 December, 18 January,
and 27 February. Nothing is known about growth in A. icoodi; if
it is similar to that in the small species A. cupreus, A. humilis, A.
intermediu.s, and A. limifrons, these large young would be in their
third or fourtli month. However, because of its large size and low
temperature, A. woodi is probably more like the montane A. tropi-
dolepis. If growth in A. woodi is analogous to that in A. tropido-
lepis the 55-65 mm young would represent hatching in March, May,
June, and July, from eggs laid several weeks earlier in each instance.
Hence, the few records of gravid females and of young indicate
egg-laying dates well scattered throughout the year, but records are
too few to show seasonal change.

COSTA RICAN ANGLES 33

Interactions. — On several occasions individuals of A. icoocU were
found in proximity but no interactions were seen. In an attempt to
photograph aggressive displays, several individuals were transferred
from their own tree trunks and released or tethered near adult
males. In other instances a mirror on the end of a rod was pre-
sented to a male in the field, and adult males were placed together
in the same container. All these tests were unsuccessful in eliciting
an aggressive response. Instead, the lizard would crouch to conceal
itself or would move away because innate wariness inhibited any
social interaction while the investigator was in the vicinity.

On 1 March 1974 a juvenile (60 mm) male A. icoodi was con-
fined with a juvenile male A. in.s/gn/.s of approximately the same
size, and several adult male A. intermedius which were slightly
smaller. Almost immediately a male A. intermedius displayed, and
the display was then returned by all other anoles including the
juvenile A. icoodi. For an hour that the lizards were kept together,
periods of vigorous displaying were frequent but alternated with
periods of relative quiescence and periods of excitement when one
individual, attempting to escape panicked others causing all to
abandon their positions and aggressive postures in a general scram-
ble. Presumably males occupy mutually exclusive territories and
maintain their spacing by aggressive encounters, which are inhib-
ited by presence of humans.

Anolis lionotus Cope

Description. — This is a medium-large, slender species with ver-
tically flattened tail, relatively small head, shortened muzzle, and
a pair of cream-colored lateral stripes extending from behind the
eye posteriorly to the groin. Adults of the population studied vary
from 56 to (S5 mm (mean 71.5 in 19 males and 60.6 in 24 females).
Weights averaged 9.5 grams (5.2 to 13.7) in four males and a fe-
male of average size weighed 6.9 grams. The male has a large, pale
orange dewlap which is lacking in the female; in three adults males
dewlaps averaged 415 mm-. In a series of preserved A. lionotus,
the female average was 95% of male length. Except for the absence
of the dewlap in the female, the sexes are not noticeably different
in color or pattern.

Habitat and behavior. — A. lionotus is normally limited to ri-
parian habitat, preferring medium-sized, fairly swift streams and
living mainly below high water mark. Rocks either bare or algae-
covered, logs, and accumulations of drift provide look-outs and
hiding places. The lizards enter the water freely, and swim and
dive well.

Temperature. — In Panama, Campbell (1971) found a mean body
temperature of 26.4°C (26.0 to 26.8) in 13 A. lionotus. He noted

34 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

that these anoles are hehophobic and do not bask, and their activity
range is considerably lower than those of most iguanids.

Reproductive cycle. — It was tentatively concluded that. ". . . in
the region of San Miguel, reproduction occurs throughout the year
with no important seasonal change" (Fitch, 1973a). This statement
was based upon the fact that all adult females captured appeared
gravid and that young of various sizes were always present, with
no one size-group predominating . The site of this study was on the
northeast side of Volcan Poas at 500 m in an area of unusually
high precipitation with mild and uniform year-round temperature.
Specimens in the University of Kansas Museum of Natural History
collection, totalling 84, were examined, and nearly all of them were
from the Caribbean versant of Costa Rica. Most of these were col-
lected in March and July, a few in May, June, and August. Gravid
females and young of various sizes including hatchlings were prom-
inent in both the March and July series, substantiating the belief
that reproduction occurs throughout the year.

A. lionotus is widespread in Costa Rica and occurs in the rela-
tively dry climate of Guanacaste as well as in the wet Caribbean
versant. A series of 19 recorded at Tilaran (24 km NW of Monte-
verde at 562 m) 21 February 1974 (about the middle of the dry
season) included young of various sizes.

Interactions. — No interactions between individuals of A. lionotus
were seen under natural conditions, although where they were
abundant two or more individuals sometimes came into close prox-
imity, as when they took shelter in the same mass of driftwood in
escaping the collector. On 21 February 1974 at Tilaran three re-
cently caught males and a female were placed together in a con-
tainer in an attempt to photograph the aggressive display. For
more than two hours that they were kept under ol^servation they
showed no aggressive behavior, but cither lay quiescent or, from
time to time, panicked by each others' movements, scrambled about
the container in an attempt to escape. On the following day the
attempt was repeated with the same group of lizards and with a
male A. pentaprion. Almost immediately the A. pentoprion dis-
played, an A. lionotus returned the challenge, and soon all males
were displaying vigorously.

A. lionotus may occur sympatrically with all the other native
mainland Costa Rican anoles, and overlaps most of them widely.
However, its streamside habitat removes it from competition with
most kinds. The highly arboreal A. hiporcotus, A. pentaprion, and
A. insignis are well segregated, and scansorial species, including A.
woodi, A. limifrons, A. carpenteri, A. lemurinus, A. sericeus, A. in-
termedins, and A. tropidolepis, would rarely come into contact with
it even where both were abundant. Interactions with the more
terrestrial A. cupreus and A. humilis would be somewhat more im-

COSTA RICAN ANGLES 35

portant, and are discussed under the accounts of those species. A.
aquaticus and A. pohjiepis, both confined to southwestern Costa
Rica, may not overlap A. lionotus, if overhipping does occur, it in-
volves a relatively small area in each case. However, A. aquaticus
is the only Costa Rican species that is like A. lionotus in habits and
habitat preference. If the two occurred together, competition prob-
ably would be severe.

Anolis pentaprion Cope
PI. I

Description. — This is a medium-large, stout-bodied species, with
a large head, relatively short legs and tail, flattened body, and pale
olive dorsal color with faintly mottled or reticulate darker mark-
ings. Eleven preserved adult specimens varied from 55 to 79 mm
(SVL), mean 74.2 in five males and 71.1 in 9 females. A male
smaller than average (65 mm) weighed 4.2 g. The dewlap is large,
approximately 650 mm- in average adult males, bright red, with
scales blue. The female has a dewlap which is only slightly smaller
than the male's. The sexes are similar in color and pattern. Female
to male ratio in linear dimensions was 96.0% in the small series
examined.

Habitat. — A. pentaprion is highly arboreal. Those found have
been at heights from ground level up to about 10 m. Trees used in
observed instances were small or medium-sized, with trunk diam-
eters from 0.1 to 0.3 m and were in open, sunlit places. The only
A. pentaprion seen on the Caribbean versant was in a cacao grove
at Beverly, and the species is more common in the relatively dry
climate of Guanacaste and northern Puntarenas provinces, but is
nowhere abundant.

Temperature. — Two adults captured at Boca de Barranca in 1968
had body temperatures of 33.4"C and 29.3; adjacent air temper-
atures were 29.9 and 28.6. Campbell (1971) also noted preference
for a relatively high body temperature. He kept an A. pentaprion
in a temperature gradient and obtained a mean of 33 (range 26.7-
37.2) for 12 readings alongside the lizard. He recorded cloacal
temperatures of 33 and 36.5 in this individual while it was in the
gradient tank. Only A. sericeus and A. cupreus attain comparably
high body temperatures.

Reproductive cycle. — At Palenque in the lowlands of northeast-
ern Chiapas, Mexico, 7 July to 2 August, Smith and Kerster (1955)
obtained 49 hatchlings from eggs found in bromeliads, but no adults
were seen. Concentrated reproductive activity early in the rainy
season is indicated and egg-laying does not occur during the dry
season. In the much drier climate of Guanacaste and northern
Puntarenas provinces, Costa Rica, reproduction might be limited to
the wetter part of the year. Most anoles oviposit in sheltered places

36 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

in leaf litter or beneath objects or even in burrows; in A. pentaprion
the habit of laying in bromeliads seems to be an arboreal speciali-
zation that would render the eggs even more vulnerable to drought
than they would be on or in the ground.

Interactions. — In the more humid part of its range A. pentaprion
is sympatric with the large arboreal species A. biporcatus and A.
capito, which might compete with it or even might be predators
on it. A. capito especially is limited to dense forest in deep shade
and probably seldom or never interacts with A. pentaprion. A.
biporcatus also differs from A. pentaprion in its preference for
denser forest and larger trees, but interaction may occur occasion-
ally. A. biporcatus is approximately four times the bulk of A. penta-
prion. A. lemuriniis is approximately the same size as A. pentaprion,
but its limitation to well-sheltered situations in deep shade low on
tree trunks would eliminate most competition. At Rio Congo and
Boca de Barranca A. pentaprion was found closely associated with
both A. cupreus and A. sericeus. Because of the rarity of A. penta-
prion no actual interactions with either were observed, but A.
sericeus, being the more arboreal, overlapped most the habitat niche
of A. pentaprion; interactions must occur. A. pentaprion is approxi-
mately four times the bulk of A. .sericeus, and conceivably preys on
this smaller species.

Anolis lemurinus Cope

Description. — This is a medium-sized, dark-colored species with
fairly long limbs and tail. Eight adults (females) from La Selva
averaged 57.1 mm (53 to 60) and 3.95 grams (3.5 to 4.0). In a
series of preserved specimens the 17 males averaged 55.2 mm, 97%
of the average 57.0 for 13 females. The dewlap is dark maroon,
with scales black and averaged 204 mm- in three males. The female
has a dewlap like the male's but smaller, about 23% of the male's
area. The male pattern is olive brown with several darker mid-
dorsal blotches and with tail and limbs banded or mottled with
darker pigment. Females are polymorphic and may have a male
type pattern, or may have a series of dark diamond shaped mid-
dorsal markings, or may have a broad, pale, pinkish or yellowish,
black-edged mid-dorsal band.

Habitat and behavior. — A. lemurinus was found in forest at Tur-
rialba and La Selva. The lizards were found from ground level up
to 1.5 m, usually on trees 0.5 m or more in trunk diameter. In most
instances they were on root l^uttresses of large trees, or on stilt roots
or on tree trunks, in sheltered places, such as a hollow or depression,
with dense foliage of vines or epiphytes, screening them from view.
The lizards were not active or wary, but seemed to depend on con-
cealing cover and cryptic behavior to escape capture. See PI. I.

Temperature. — Four body temperatures, all of immatures, at

COSTA RICAN ANGLES 37

Finca Le Selva in February, 1974, averaged 27.1°C. Body temper-
ature averaged 1.9 above adjacent air temperature. The few records
that are available indicate that temperature in A. lemtirinus is sim-
ilar to that in the closely associated A. Umifrons.

Reproductive cycle. — Females captured at La Selva in May (1),
July (1), September (3), and December (1) were obviously dis-
tended with eggs. A first-month juvenile (26 mm) found on 3
February must have hatched from an egg laid several weeks before,
perhaps in December. Nine larger young, 39 to 47 mm, were cap-
tured in the period early February to mid-May. They were judged
to be 2 to 4/2 months old and to indicate possible egg-laying from
October through January.

Interactions. — Individuals of A. lemurimis were always found
alone and, because of their scarcity, no intraspecific encounters were
seen. However, when several males were confined together, they
displayed, although not as readily as some of the smaller species
and no actual attacks were observed.

Interspecific interactions could be expected to occur mainly with
A. Umifrons, A. Jmniilis, and A. carpenteri, which all were found in
the same habitat with A. leniurinus, and sometimes on the same
tree trunks, although average differences in their preferences are
evident. All three species arc only about ]i of the bulk of A. lemu-
rimis, and could be easily dominated by it, conceivably, even preyed
upon by it. Other interacting species are the large A. hiporcatus
and A. capito. A. hiporcatus is about 4/2 times the bulk of A. leniu-
rinus, and an actual case of predation on a nearly, full-grown A.
lemurinus by an A. hiporcatus is cited under the account of the latter
species. A. capito also is a known predator on other lizards, is
similar to A. lemurinus in habitat preference, and is up to three
times the bulk of A. lemurimis.

In Costa Rica the range of A. lemurinus probably does not con-
tact those of either A. cupreus or A. sericeus, but farther northwest,
in southern Guatemala, all three occur together. A. cupreus is the
medium-sized species of the three, and averages 62% heavier in
weight there than in Guanacaste. Males of A. lemurinus also are
larger in sympatry with A. cupreus in southern Guatemala — b}' 21%
in length and 100% in weight.

Anolis hiporcatus (Wiegmann)

Description. — This is a large, bright green species, with a rela-
tively large head and long muzzle and enlarged toe pads. In 39
preserved adults (KUMNH), males averaged 88.8 mm (SVL) and
females averaged 89.2, with no significant difference. The dewlap
is orange tinted with a bluish inner part (Williams, 1966), well-
developed in the female but much larger in the male. Three adult
females weighed 20.0, 18.0 and 17.5 grams.

38 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

Habitat. — A. biporactus seems to be highly arboreal. It may
climb on stems of shrubs, small trees, or tree trunks near ground
level, or may be high in large trees. Too few records are available
to show what kinds and sizes of trees and what heights are pre-
ferred.

Temperature. — No body temperatures are available, but, judg-
ing from the behavior of A. biporcatus kept in confinement, these
anoles have some tendency to bask when sunshine is available;
hence, their body temperatures may at times be above air temper-
ature. Capacity for rapid color change (green to brown) in A.
biporcatus is greater than in any other species noted. These changes
in color may have some part in thermoregulation, by affecting ab-
sorption, as well as having a cryptic function.

Reproduction. — Henderson (1972) recorded a female that laid
two eggs on the same day in March, thus deviating from the usual
schedule of one egg at a time in anoles. A large female from Tikal,
Guatemala, contained a shelled egg ready to be laid on 28 March
1973. The date was late in the dry season, the time of year when
reproduction has stopped or reached its lowest ebb in some kinds
of Central American anoles. Egg-laying may occur year-round.
McCoy ( 1975 ) reported that of seven adult females from south-
eastern Guatemala, 29 August to 21 December, two were not gravid,
two had oviducal eggs on both left and right sides, and three each
had a single oviducal egg.

Interactions. — A. biporcatus is much larger and much more
arboreal than most of the other species. Only A. insignis, A. capito,
A. woodi, and A. pentaprion are as large or larger and thus might
compete for the same resources. A. insignis and A. ivoodi are gen-
erally at higher elevations and altitudinal overlap is not definitely
known; A. capito and A. biporcatus are widely sympatric, but A.
capito prefers perches on large tree trunks near the ground and
A. biporcatus may climb high in trees. A. pentaprion is widely
sympatric with A. biporcatus but, perhaps because both are rare,
they have not been found in the same locality; A. pentaprion is
commoner on the Pacific versant where A. biporcatus is absent. The
two are believed to be closely related, as both belong to the Petersi
Series and the Beta Division within the genus.

For smaller species A. biporcatus is a predator. Taylor (1956)
related that an adult of 88 mm captured at Suretka had eaten an
individual of A. lemurinus of 50 mm, but feet of the smaller lizard
still protruded from the mouth of the larger, and evidently the prey
was too large to be engulfed all at once. \A^eight ratio of prey to
predator in this case would have been about 1 to 5. Adults of A.
carpenteri, A. humilis, A. limifrons, and A. sericeus are of a size
that can be easily swallowed by adults of A. biporcatus, with weight
ratios between 1-10 and 1-15. In addition, immatures of A. capito,

COSTA RICAN ANGLES 39

A. lemiirinus, A. lionotus, and A. pentaprion would be vulnerable
to predation by A. biporcatus.

Anolis sericeus Hallowell

Description. — In this small, extremely slender, pale colored, gray
or brown species, adults vary from 36 to 52 mm ( SVL ) , mean 42.7
in 12 males and 39.0 in 14 females. Weights varied from 0.7 to 1.7
g and averaged 1.05. The dewlap is bright orange with a central
indigo spot and is approximately 150 mm- in males of average size.
The female has a relatively small dewlap with 13% of the male's
area. In a series of 82 ( 52 males and 30 females ) from the southern
parts of Oaxaca and Chiapas, Mexico, females averaged 89.0% of
male length and 77.7% of male weight. Females are dimorphic in
pattern, having a broad, pale dorsal band, or a nondescript male-
t\'pe pattern with no conspicuous marks but with a series of small
mid-dorsal black spots.

Hohitat. — A. sericeus is scansorial, on small or medium-sized
trees, in relatively open and xeric situations. Most of those found
were on fence posts at heights between 1.0 and 1.5 m, at Rio Congo,
La Irma, Playas del Coco, Sardinal, Boca de Barranca and Monte-
verde.

Temperature. — "Body temperatures . . . were clustered in a
six-degree range with a preferendum evidently between 32 and 33
— notably higher than in most other species. . ." (Fitch 1973a)

Reproductive cycle. — In the seasonally dry Pacific versant where
A. sericeus occurs, from Central Costa Rica northwest into Oaxaca
it stops reproduction during the dry season, December to April. Too
few individuals have been found in the relatively wet climate of the
Caribbean versant to show whether the same pattern is maintained
there or whether, as might be expected, the breeding season is less
well-defined, with some reproduction throughout the year.

Interactions. — A. cupreus is the one species that overlaps A.
sericeus most extensively, both in geographic range and in habits
and habitat. Each might be expected to affect the other to an im-
portant degree. Their sympatry extends through the Pacific versant
from near Puntarenas, Costa Rica, northwest through Nicaragua,
Honduras, El Salvador, and Cuatemala to San Jose. In Costa Rica,
A. sericeus is definitely more scansorial and more tolerant of xeric
conditions, and wherever it occurs A. cupreus is present in higher
densities. Northward, in the area of sympatry, A. sericeus becomes
relatively more numerous. Compared with allopatric Chiapan A.
sericeus, beyond the range of A. cupreus, sympatric A. sericeus from
Costa Rica are smaller (95% in length), perhaps showing character
displacement.

40 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

Anolis aquaticus Taylor

Description. — This is a medium-sized, dull-colored species with
a relatively small head, short, vertically compressed tail, broad, dark
transverse bands on the body, tail and limbs, and blue eyes. Adults
vary from 47 to 78 mm (SVL), mean 62.3 in 12 males and 59.7 in
10 females (preserved). Weight averaged 7.8 g in 5 adult males.
The dewlap is dull yellowish-orange with white scales and with
four longitudinal blood-red bands that are slightly broader than the
intervening spaces. The two middle bands are best-developed. The
dewlap averages 567 mm- in 18 adult males. The female lacks a
dewlap but othei-wise is like the male in color and pattern and is
96.0% of male length.

Habitat and behavior. — A. aquaticus lives along small, swift,
rocky streams in cool, well-shaded places, perching on rocks, logs,
and sticks at the edge of the water or in midstream. It lams into the
water without hesitation, and swims and dives well. In escaping it
swims under piles of driftwood and debris, or beneath submerged
rocks, or it may enter holes in the bank.

Temperature. — No body temperatures were obtained, but body
temperature is relatively low because these anoles do not bask, stay
in deep shade, and are often in the water or in wet places cooled
by evaporation. The species is like A. lionotus in habits, but where
it lives at higher elevations its body temperature may average sev-
eral degrees lower than the 26-27°C characteristic of A. lionotus.
On two occasions when recently captured individuals of A. aqua-
ticus were carried for periods of minutes in collector's hand, they
seemed to suffer from shock, perhaps as a result of overheating.
Confined individuals showed distress if even briefly exposed to weak
sunlight. Lack of tolerance for high temperatures was indicated.

Reproductive cycle. — A. aquaticus was observed in the field only
at Las Cruces in mid-March, 1973, and late February, 1974. At that
season adults and young of various sizes were present, suggesting
year-round reproduction.

Interactions. — When groups of males were confined together in
attempts to film the aggressive display, efforts were wholly unsuc-
cessful. The lizards only tried to escape or conceal themselves.
Aggressive behavior was inhibited by presence of persons, or by
unnatural conditions. Interactions were not seen under natural con-
ditions either, although sometimes two or more anoles were in close
proximity. Their shyness toward humans, and long flushing distance
was an inhibiting factor here also.

A. pohjiepis was the only other species found in the same area
with A. aquaticus, but it was in relatively open situations and
usually was above ground level. Hence interactions would be rare
or lacking, even where both kinds were common.

COSTA RICAN ANGLES 41

Anolis capito Peters

Description. — This is a large, long-legged, short-headed species
olive brown dorsally, uniform or mottled, or with three darker,
jagged transverse bands on the body and sharply defined V-shaped
band between the eyes. Adults vary from at least 69 to 95 mm
(SVL), mean 78.9 in 27 males and 86.6 in 25 females. Eight males
averaged 8.49 g and two females averaged 13.1 g. Females are
polymorphic; some have the banded male pattern, others have a
broad, pale brown, black-edged middorsal longitudinal stripe, or
have a series of middorsal diamond-shaped markings. The dewlap
is remarkably small (72 mm- in a male of 73 mm SVL) and dull,
greenish yellow. It is much smaller in the female than in the male.
Adult females averaged approximately 110.0% of male length and
155.0% of male weight.

Habitat. — At Finca La Selva these anoles were usually found on
the trunks of large forest trees near their bases. In eight whose
position was recorded, average height was 0.6 m; three were on the
ground, and the highest was 2 m. Those on the ground were always
near the bases of trees. Most were on large trees with wide root
buttresses, but some were on smaller trees, including cacao.

At Rincon de Osa, Paul B. Robertson (ms) found A. capito at
heights of 0.9 to 1.8 m on large or small tree trunks, and on stems
down to a minimum size equal to the lizards' body diameter. He
found that the anoles come to the ground from time to time and
may make forays as far as 3 m from the perch tree.

Temperature. — Two body temperatures obtained at La Selva
were 26.2°C and 27.2, 0.7 and 0.6 degrees above nearby air tem-
perature. Campbell ( 1971 ) kept one individual in a tank with a
temperature gradient. It spent 67.7% of its time between 23.2 and
23.6, 20.8% between 24.0 and 24.9, 11.5% between 25.0 and 25.5.

Reproductive cycle. — A high proportion of those captured at
Finca La Selva, 26 of 41, were immatures 25 to 53 mm (SVL), and
these juveniles were well-distributed throughout the year. From
analogy with other species the following tentative size-to-age cor-
relation is proposed: 25 to 36 mm, first month; 37 to 45, second
month; 46 to 53, third month. On this basis the juveniles, collec-
tively, represent egg-laying in eveiy month of the year.

Interactions. — Because of the scarcity of these anoles at Finca
La Selva, all were found singly and no interaction was observed,
but the spacing, with each on its own tree trunk suggested terri-
toriality. At Rincon de Osa where the species is more common,
Paul B. Robertson (ms) also observed that individuals were segre-
gated on separate tree trunks and he concluded that both sexes
maintain exclusive territories with surface areas of about 14.5 m-.
The territory usually includes several trees and understory shrubs.

42 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

which are used as perches. Males that Robertson experimentally
introduced into the territories of others were repulsed and driven
out by displays and/ or attacks. Hence, it seems that territoriality
is well developed in A. capito, although the male dewlap is much
smaller than in any of the other species studied, and the female-
to-male size ratio is much greater.

Interactions must be most frequent with the abundant small
species, A. limifrons, A. humilis and A. carpenteri. These average
about 10% of the bulk of A. capito, and are potential prey for it. On
the Pacific versant A. capito and A. polylepis are both common in
rain forest. At Rincon de Osa, Paul B. Robertson (ms) found an
adult male A. polylepis in the stomach of an individual of A. capito.
The size ratio of these two species is about one to five.

Anolis hiporcatus is another large arboreal species, and it might
compete with A. capito. However, on the average, A. hiporcatus
occurs higher and is not confined to the trunks as is A. capito. When
interactions do occur, A. hiporcatus must have the advantage be-
cause it is more active and larger (at least twice the bulk of male
A. capito), and it could be expected to prey upon the young of A.
capito.

More than any other species, A. lemurinus is similar to A. capito
in habitat, as both live on trunks of large trees in rain forest. How-
ever, A. lemurinus requires more sheltered sites, with overhang and
screening foliage, whereas A. capito perches in the open. Both are
rather sluggish and ciyptic in behavior. A. capito is two to three
times the bulk of A. lemurinus, and might prey on this smaller spe-
cies, especially on the young. A. peritaprion may interact with A.
capito occasionally, but it is much more arboreal and prefers open,
sunlit habitat. A. lionotus and A. aquaticus are largely limited to
streamcourses, and would rarely interact with A. capito; both are
smaller.

Anolis polylepis Peters

Description. — This is a small, slender, light olive brown species
with long, slender limbs and tail. Adults vary from 41 to 57 mm,
mean 50.9 mm in 41 males and 47.2 mm in 46 females (preserved).
Weights averaged 2.0 in seven (six males and one female). The
dewlap is medium large (mean 255 mm- in 30) and light orange
in the male; it is lacking in the female.

Hahitat and hehamor. — Andrews (1971a) made an intensive
study of A. polylepis at Rincon de Osa, Puntarenas Province. She
found that adult males occupy territories with mean size of 157 m-
whereas adult females are limited to smaller areas, with a mean of
37 m-. Perch height is affected by size and sex of the indixidual,
and by season, time of day and type of activity. Mean perch height
of adult males was 72 cm in March ( the dry season when food was

COSTA RICAN ANGLES 43

scarce, leading to more emphasis on finding food — generally on the
ground) and 92 cm in an April-July sample (in the wet season
when territoriality and courtship came into greater prominence).
Corresponding figures for the same seasons in adult females were
44 and 49 cm. Of 286 anoles 30% was perched on leaves, 25% was
on stems of 7 mm or less, 16% was on perches of 8 to 14 mm, 12%
on perches of 15 to 29, 11% on perches of 30 to 99 mm, and 6% on
perches of 100 mm or more.

Temperature. — Four body temperatures obtained at Las Cruces,
San Vito, averaged 26.3°C (24.5 to 28.0) and averaged 1-6 above
adjacent air temperature. Clark ( 1973 ) obtained 100 body temper-
atures on three consecutive days at Rincon de Osa in lowland rain
forest 56 km west of Las Cruces. Air temperature averaged approx-
imately 27, and under varied weather conditions (overcast, rainy,
sunny) it was found that the average body temperature was within
one degree of air temperature. Body temperatures ranged from 20.9
to 29.3, with a tendency toward average increase in the early morn-
ing hours and stabilization during the afternoon hours. Clark stated
that it would be pointless to compute a "preferred" temperature,
because the lizards seem to be behaviorally indifferent through the
entire range of recorded environmental temperatures. However,
almost /3 of the body temperatures were within the three-degree
range 25 to 28, with many more (29) between 25 and 26 than in
any other one-degree temperature range. Relatively few body
temperatures were below 23.5 or above 28.5.

At this same locality in August, Hertz (1974) obtained 50 body
temperatures of active anoles which averaged 27.8 ± 0.17 (26.0-
31.2), Like Clark he emphasized the "thermal passivity" of the
lizards, which did not attempt to thermoregulate even when patches
of sunlight were available. He suggested that tropical anoles of this
and other species are fundamentally different from some other liz-
ards, notably those of deserts, in that they are adapted to be active
over a wide range of body temperature. Behavorial thermoregu-
lation is not prominent in their behavior because ". . . the relative
cost of basking in the forest is high."

Reproductive cycle. — Andrews (1971b) stated that at Rincon de
Osa females continuously mature clutches of one egg each through-
out the year, ". . . probably as fast as the necessary metabolites can
be accumulated." Although she did not compare reproductive rates
in the dry season and rainy season, she emphasized the relatively
scarcity of food in the dry season. At Las Cruces late in the dry
season the population consisted mostly of adults, and the young
seen were well above hatchling size, indicating that egg-laying must
have slowed down or even stopped for a period of weeks.

Interaction,s. — Species known to occur syntopically with A.
pohjlepis are A. capita, A. aquaticus, and A. humilis. In each in-

44 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

stance, observed or probable interactions are discussed under the
heading of those species. Also, A. limifrons overlaps A. pohjlepis
in some areas of rain forest in southwestern Costa Rica. It is only
about half the bulk of A. pohjlepis but in general habits and habi-
tats are similar.

Anolis insignis Cope

Description. — This is a short-legged giant species, pale yellowish
brown with traces of greenish suffusion, and with transverse double
bands of purplish brown edged with black on the body. There is
a distinctive black circle with a pale brown center on the side of
the neck in front of the foreleg insertion. Adults may attain a length
(SV) of 140 mm or slightly more. Extent of sexual dimorphism is
unknown. The dewlap is large, dull white, with four longitudinal
reddish orange streaks near its outer edge. The female has a dewlap
smaller than the male's.

Habitat and beJmvior. — An adult female was found on the
ground at the base of a cypress tree, and a hatchling male was found
in a cypress, 2.5 m high on a horizontal branch 2 cm in diameter.
Presumably, these lizards are highly arboreal and are rarely seen
because they are usually high in forest trees.

Temperature. — No records of body temperature were obtained.
In the submontane forest habitat where A. insi[i,nis occurs environ-
mental temperatures are relatively low and opportunities for bask-
ing are limited. Like A. JuimiJis, A. woocU, and A. lionotus, A.
insignis is probably a non-basker. Body temperatures in the neigh-
borhood of 20 °C are to be expected.

Reproductive cycle. — A hatchling was captured at Monteverde
on 1 March 1974.

Interactions. — The hatchling male captured on 1 March 1974,
placed in a container with other anoles of the same size including
a juvenile A. woodi and several adults male of A. intermedins, re-
sponded immediately with vigorous aggressive displays, soon caus-
ing all the other lizards to respond with displays of their own.
However, the hatchling A. insignis was the most aggressive and
persistent. This aggressiveness of a mere hatchling, and the posses-
sion of a well-developed dewlap in the adult female, suggest that
A. insignis is a highly territorial species.

The hatchling's aggressiveness would permit it to hold its own
against adults of abundant small species, such as intermedins. How-
ever, interactions between A. insignis and the other species might
involve mainly predation by the large A. insignis. Although no
weights of adult A. insignis were obtained, it is estimated that they
weigh from twice to more than 30 times as much as the other
species here discussed, and hence might prey on any of them. Inter-

COSTA RICAN ANGLES 45

actions might be expected most frequently with A. looodi and A.
intermedins and perhaps with A. humilis.

Anolis cristatellus Dumeril and Bibron
PI. II

Description. — This is a dull brown, medium-sized, large-headed,
chunky-bodied species in which the tail is laterally compressed and
bears a prominent, fin-like crest supported by the dorsal spines of
the vertebrae. Adult size ranges from 55 to 70 mm (mean 62.0 in
16 males and 58.8 in 14 females). A large adult weighed 6.35 g.
There is a dewlap, variable in color, with brown, red or yellow,
well-developed in both sexes and somewhat larger in the male. The
caudal crest also is more prominent in the male, about twice as high
as the female's, and deeply scalloped along its dorsal margin. The
pattern is highly variable, usually with a series of transverse dorsal
bars in the male and a series of middorsal overlapping, diamond-
shaped marks, or a broad, middorsal band in the female.

Habitat and behavior. — In its homeland in Puerto Rico and in the
Virgin Islands, Anolis cristatellus occurs in a wide variety of habi-
tats including forest, scrub, dry rocky areas, and situations grossly
disturbed by man. In the city park at Limon the lizards were found
on giant fig trees. The few adults seen were at heights between 1
and 3 m; but many young were near ground level. The lizards
reacted to approach of a person by moving upward and seeking
concealment in the tangle of interlacing roots that made the fig trees
exceptionally secure abodes.

Reproductive cycle. — On 19 March 1975 I observed these anoles
in the city park at Limon, where they seemed to be undergoing a
population explosion. However, they seemed to be limited to the
park, an area of about one city block, and within it were limited
to a few large fig trees; nevertheless, the population must have
totalled well over a hundred individuals and perhaps was several
hundred. All but a few of those seen were juveniles, ranging from
hatchlings up to halfgrown size.

Savage (1973) first recorded the species from Costa Rica, per-
haps on the basis of the Limon colony, but he did not specify any
locality, merely indicating that A. cristatellus occurred in the south-
eastern sector of the country. I am not aware of how or when the
colony became established, but it must have come about through
human agency, either intentionally or accidentally.

From March 1965 through March 1970 this same park was a
study area where, at intervals of weeks or months, I observed a pop-
ulation of sphaerodactylinc geckos (Gonatodes alhogularis). They,
like the anoles, were abundant about the bases of the large fig trees,
but were largely crepuscular rather than diurnal. When the anole
colony was observed in March 1975, no geckos could be found. In

46 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

the five-year interval since my earlier observation they had been
eliminated, or at least had become much scarcer, perhaps because
of predation by, and/or competition from A. cristateUus, since no
other environmental factors were noticeably altered.

The population structure of these anoles observed at Limon in
March 1975 was remarkable in having a higher ratio of young to
adults than any reptile population that I have observed elsewhere,
indicating that it had undergone a period of intensive and highly
successful reproduction. The smallest individuals, newly emerged
hatchlings, must have come from eggs laid several weeks earlier.
From these smallest young, there appeared to be a continuum in
size up to individuals more than twice their length and probably
several months old. A high level of reproduction in the autumn
months through January is indicated. This is one of the wetter
parts of the year at Limon, but the climate there is notably warm
and humid, and some reproduction throughout the year is to be
expected.

Interactio7is. — The recently established and thriving population
of A. cristateUus at Limon has not yet come into contact with native
Costa Rican anoles. Presumably, its successful establishment and
increase is correlated with the absence of both predators and con-
generic competitors in the artificial habitat of the park, and a spread
to more natural habitats cannot be expected. Williams' (1969) studies
have shown that some West Indian anoles are often able to reach
new areas by overseas travel as waifs, but that successful establish-
ment is unlikely if the land mass is already inhabited by a native
species.

Discussion

The 17 species of Costa Rican Anolis studied belong to five
different "species series" of the genus, and the ecological and mor-
phological trends revealed show some correlation with phylogenetic
groupings. Ethcridge (1960) recognized Alpha and Beta sections
of the genus, partly separated geographically and distinguished by
small but consistent anatomical differences; later workers have
unanimously accepted his arrangement. Of the 17 species studied
only A. itisignis and A. cristateUus are in the Alpha section (in dif-
ferent species series), but other Costa Rican anoles that were not
found, A. chocorum, A. frenatus, and A. microtiis, also are in this
section. The giant size and highly arboreal habits of A. insignis
and the female dewlaps of A. insignis and A. cristateUus that set
them off from most of the other 15 species, are not characteristic of
the Alpha section as a whole.

The Beta section, containing the remaining 15 species, has re-
cently been characterized by Savage ( 1973 ) as a distinct genus,
Norops, but it is doubtful that this generic partitioning will be gen-

COSTA RICAN ANGLES 47

erally accepted. Three "species series" in the Beta section are rep-
resented by the 15 species here studied. A. capita, A. biporcattis,
and A. pentaprion belong to the Petersi species series, which con-
tains few otlier species. All are large and arboreal, but otherwise
they have little in coninion. The Fiiscoaitratus species scries in-
cludes A. carpenteri, A. limifrons, A. liOnotiis, and A. polylcpis of
this study, and numerous others in Central America and South
America. A. carpenteri and A. limifrons are similar in size and
proportions; otherwise the four species have little in common. The
ChrijsoJepis species series is the largest in the genus, and it includes
eight of the species in this study: A. aquaticus, A. cupreus, A.
hiimilis, A. intermedins, A. lemnrinns, A. sericeus, A. tropidolepis,
and A. woodi. All but A. woodi are medium to small, but they are
remarkably diverse in habitats, behavior, preferred temperatures,
and amount of sexual dimorphism.

One of the most obvious ways in which sympatric species affect
each other is in drawing upon the same food resources. Anoles in
general are insectivorous and are not highly selective in their choice
of prey. In feeding they respond to visual cues, are attracted by
movement, are inclined to take anything within a wide size range,
but reject certain sematic types. Interspecific competition may be
avoided or alleviated by divergent adaptation for different types of
prey, for different sizes of prey, or for different microhabitats. With
some exceptions, size of prey tends to be somewhat proportioned
to size of the lizard (Fig. 3), and extent of overlap in food can be
estimated from the extent of overlap in size and/or in microhabitat
in otherwise similar species.

Little is known about the specific food habits of most kinds of
mainland anoles. A. lionotus and A. aqnaticus are so distinct from
all others in habitat that they probably do not compete for food.
Of the species here considered, A. limifrons is one of the best known,
through the work of Sexton et al. ( 1972) in the Panama Canal Zone.
Their study was addressed to size and quantity of prey; concerning
kinds of prey they only stated that it consists of insects, isopods,
and arachnids. Some of the most significant findings of this study,
based on 512 anoles, were that approximately two-thirds of the liz-
ards contained a single prey item in the stomach regardless of time
of day or season, that prey items were mostly in the length range
4 to 10 mm, with sharply declining numbers smaller than 4 mm
and gradually declining numbers larger than 10 mm up to a maxi-
mum of 32 mm. In this the lizards were exercising discrimination,
mainly in rejecting minute animals, which sampling revealed to be
far more abundant and varied than were those in the sizes classes
actually taken. Adult males, females, and juveniles were found to
take prey mostly from the same size classes with only average dif-
ferences. More female than male lizards had food in their stomachs.

48 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

BIPORCATUS

WOODI o— •-

CAPITO • o

LIONOTUS o-^

PENTAPRION

AQUATIC US

-o-«-

LEMURINUS ^^^

TROPIDOLEPIS
POLYLEPIS
INTERMEDIUS

SERICEUS
CUPREUS

-♦O CARPENTER!

LIMIFRONS
HUMILIS

30 40 50 60 70 80 90 100

SNOUT VENT LENGTH IN MILLIMETERS

Fig 3. — Diagram showing sizes and sexual diflerences in \arious species of
native Costa Rican anoles; solid circles show mean sizes of adult males; open
circles show mean sizes of adult females; horizontal lines show known size
ranges for adults. Not included is Anolis insignis, which is much larger than
any of the other species and does not overlap them.

The autliors concluded that the Hzards did not undergo food stress
in the dry season (which was not especially severe at that locality)
because there was no seasonal change in frequency of fed versus
unfed adults or in number of food items per stomach.

At Finca La Selva I obtained occasional field observations on
the feeding of A. limifrons. Sixteen captured prey animals included
6 lepidopterans ( 5 caterpillars and 1 moth ) , 3 spiders ( lycosid, sal-
ticid, oxyopid) 2 ants, a cricket, a cockroach, and a fly larva. It
seems especially noteworthy that only one of the 16 prey animals
was a volant type. At the same locality observations were also made
on the feeding of A. humilis and prey included a moth, a cater-
pillar, a cricket, a lycosid spider, an isopod, and an earthworm.
This small sample indicates similarity to A. limifrons, which also
takes most of its food from the leaf litter. However, predation on
earthworms is surprising, and may indicate utilization of a group
of prey animals not taken by other anoles. Of the five prey animals
measured, one was a caterpillar of 33 mm being eaten by an anole
of 32 mm (SVL). This caterpillar's length exceeded all prey lengths

COSTA RICAN ANGLES 49

recorded in the extensive study of A. limifrons by Sexton et al.
(1972).

Examination of 10 digestive tracts of A. tropklolepis from Haci-
enda El Prado revealed 3 hemipteran bugs, 3 beetles, 3 crickets
(gryllids and ceuthophilid ) and a caterpillar. The types of insects
found, and the slow and clumsy movements of these lizards while
feeding in captivity suggested that their prey would consist mainly
of less agile types, especially those that are flightless.

The large species, A. hiporcatus, A. capito, A. insignis, and A.
ivoodi are all potential predators on any of the smaller species with
which they come in contact. The first two named are definitely
known to carry on such predation, but only from casual records, as
food habits studies have not been made. It is still not known
whether such predation occurs only occasionally or whether some
of the large species often eat the smaller species associated with
them. A. pentapiion and A. lemurimis also are large enough to prey
on young of some of the smallest species, if so inclined.

Another consequential aspect of ecological relationships between
potentially competing species is difference in timing and amount of
reproductive effort. Anolis is noteworthy among lizards and unique
among iguanids in producing a single-egg clutch, and insofar as
known all of the manv species are alike in this respect (Hamlett,
1952; Fitch, 1970; Sm'ith et al., 1973; Andrews and Rand, 1974).
However, there seem to be interspecific differences in the frequency
with which eggs are produced, length of the annual breeding sea-
son, and the size of the egg in relation to that of the female. The
interval between successive eggs also is subject to intraspecific vari-
ation, probably affected by food intake and nutriment stored in the
fat bodies, and definitely influenced by the size and age of the in-
dividual. Large adult females more often have eggs in both ovi-
ducts than do smaller and younger females of the same species.

Andrews and Rand (1974) have discussed some of the ecological
implications of the one-egg clutch in Anolis and have compared the
reproductive effort and potential of Anolis with that of Sceloporus,
an iguanid genus in which the clutch is highly variable and is al-
ways greater than one. These authors interpreted small clutch size
in Anolis as an adaptation to facilitate frequent oviposition. Also
they considered it may be an adaptation to maintain agility by
keeping down the gravid female's weight, especially since climbing
abflity is correlated with surface area of the digital pads, and,
negatively, with the weight of the lizard. Andrews and Rand (op.
cit.) considered anoles to exemplify an extreme of r-selection in
lizards.

Little is known about the frequency and continuity of egg-laying
in most kinds of anoles. For A. limifrons of the Canal Zone, kept in
confinement, Andrews and Rand (1974) found a mean interval of

50 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

7.7 days between egg-layings during the wet season, lengthened
to 19.8 days during the dry season. In 12 free-ranging A. Jimifrons in
Costa Rica in the wet season, they found a mean interval of 8.1 days.
At Rincon de Osa they noted an interval of 13.2 days in A. pojyiepis
in the dry season. Andrews and Rand ( 1974 ) found that in A.
Umifrons in the Canal Zone a newly matured female has a life
expectancy of approximately 4.5 months, and she could be expected
to produce about 18 eggs during this time. One that survived a
whole year would produce an estimated 40 eggs but there is almost
complete population turnover from year to year.

Although no record of interval between egg-laying is available
for A. humilis, the interval is judged to be exceptionally short. One
gravid female newly captured at Beverly on 30 August 1969 laid
two normal eggs overnight. In 47.5/6 of adult females of a year-
round sample, there was an egg in each oviduct. In about one-third
of these, the two oviducal eggs were of approximately equal size,
perhaps indicating that two-egg clutches are fairly common, or that
the interval bi'twcen clutches is brief and irregular. Juveniles, in-
cluding hatchlings, were a prominent part of every field sample of
A. humilis. In a year-round sample of A. humilis (N=532) hatch-
lings (less than 21 mm, SVL) were 13.0%, while in a comparable
sample of A. Umifrons (N=2098) hatchlings (less than 23 mm,
SVL) were 5.15%.

A female of A. cupreus from San Jose, which I kept in confine-
ment, produced seven eggs at an average interval of 10 days, in late
June, July, and August (Fitch, 1973a). At this rate it is estimated
that a total of 18 eggs would be produced during the course of the
breeding season, of approximately six months. Limitation of the
breeding season to about half the year greatly reduces reproductive
potential, compared with that of species that breed throughout the
year. During the latter part of the dry season populations of A.
cupreus consist entirely of adults. Although the rainy season begins
in April, there is a lag in reproductive response and the first hatch-
lings appear in early July, with regular increments thereafter, from
August through November. The first wave of hatchlings appearing
in July may mature by the end of October or in November or early
December, in time to contribute one or more eggs to the annual
crop, but soon the onset of the dry season curtails reproductive
activity. These young adults and others maturing later make no
further contributions for several months, until the rainy season be-
gins in late April. By then their numbers have been greatly reduced
by normal mortality factors, intensified through the rigors of the dry
season. Essentially the same seasonal regimen and reproductive
constraints apply to A. sericeus, A. pentaprion and A. intermedius.
A female A. intermedius laid four eggs with average interval of
approximately 7 days in April 1975.

COSTA RICAN ANGLES 51

For A. tropidolepis evidence was obtained that egg production
continues uninterruptedly throughout the year with httle change,
and that the mean interval between eggs is in the neighborhood of
one month. Hatchlings (less than 24 mm, SVL) made up 3.7% of
the total sample, demonstrating that A. tropidolepis has a much
lower reproductive potential than A. Jimifrons or A. humilis. Growth
in this montane species is correspondingly slow, attainment of sex-
ual maturity requires a minimum of eight months, and survival for
more than a year is common.

Although all of the figures cited are subject to revision because
"hatchlings" were distinguished arbitrarily on the basis of length
with too little information on early growth, and because the true
ratios of hatchlings to older individuals may have been obscured by
behavorial traits that differ between species, it is evident that A.
humilis represents an extreme of r-selection among the species
studied. A. limifwns is less extreme, A. ciipreus still less, and A.
tropidolepis is relatively K-selected. Other kinds that probably are
like A. tropidolepis in being relatively K-selected, with delayed
maturity, are the large A. insignis and A. woodJ and perhaps A.
hiporcatiis and A. pentaprion. Like A. tropidolepis, both A. insignis
and A. iroodi live at medium or high altitudes where relatively low
temperature results in low metabolism and depressed growth rate.
As indicated by Andrews and Rand (1974), the egg and hatchling
are relatively the smallest in the largest species; hence, these large
kinds have to do more growing than the smaller kinds — another
factor in their delayed maturity.

Table 5 shows ratios of hatchlings to average-sized adult females
in the 11 Costa Rican species for which some information is avail-
able. The figures for hatchling size in A. hiporcatiis, A. humilis,
A. lemurimis and A. polylepis are from Andrews and Rand (1974).
For the other species the figures are based upon young found in the

Table 5. — Typical Ratios of Hatchling Length to Female Length in
Various Species of Costa Rican Angles

Typical length S-V in millimeters Hatchling-to- $
Adult 2 Hatchling ratio (%)

biporcatus 89 31 34

capita 87 25 29

ciipreus 36 18 50

humilis 38 17 45

intcnnvdius 45 18 40

lemtirinus 57 24.5 43

limifrons 38 16 42

lionotus 61 23 38

polylepis 47 19 40

tropidolepis 50 21 42

tvoodi 81 31 38

52 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

field, but thought to be recently-hatched because of presence of
umbihcal scars and because they were the smallest in field collec-
tions, that included hundreds of individuals each of A. cupreus,
A. intermedins, A. Umifroivi and A. tropidolepis, but were relatively
few for A. capita, A. lionotus and A. tcoodi. The table shows that
there is a fairly wide range of ratios despite the fact that all are
alike in producing a one-egg clutch. It shows that relative size of
hatchling is by far the greatest (50%) in A. cupreus, in which sexual
dimorphism is great, with the male much larger. At the opposite
extreme, with relatively small hatchling (29%), is A. capito, in which
there is also marked sexual dimorphism in size, but with the female
the larger. Other species in which sexual dimorphism is less do not
bear out this trend clearly but, regardless of whether the sexes are
approximately equal or the male or female is somewhat larger, the
hatchling-to-female ratio approximates 40 per cent in most.

Interspecific effects depend upon the degree of sympatry and
syntopy and the abundance of each of the species involved, as well
as the amount of overlap in use of essential resources. Tables 6 and
7 indicate estimated amounts of overlap for each species-pair in
perch height, body temperature, and geographic range.

Table 8 lists the 16 native species studied, with six sets of
ecological and morphological traits. In column 1 the species are

Table 6. — Estimated overlap ix perch height between species.
0=]ittle or no overlap, l=slight overlap (less than M), 2=moderate overlap
(/I to /i), 3=;extensive overlap (more than %), 4=complete or almost complete
overlap.

aquaticiis

liiporcatiis _ 0

capito 0

carpenter! _ _ 0

cin^reus 0

humilis 1

insignis 0

intermedins 0

lemurinus 0

limifrons 0

lionotus 3

pentaprion 0

polylepis — . U

sericeus 0

tropidolepis 0

woodi 0

• C7

/

.Cv

.^"

f //

1 O o" A^

o

2

o
2

s#'

/

2

o

1

1

s^"

.--^

_^y"

2

2
2
0

4

3

1

0

4

o
O

4

0

2

o
2

2
1
1

0

2
1
1
1

, -> # / /

4

4

4

1

4

2

2

2

1 ^"^ >^

0

1

4

1

1

4

4

4

1 2 ^^ ./ vi!^

3

2

3

I

1

3

3

0 4 4 4' ^

1 2 4 2 <-

2

2

2

o

o

4

4

4

3

2

2

1

2

2

2

2

0 4 2 2 3

COSTA RICAN ANGLES 53

divided into four groups on the basis of habitat; nine species are
considered typical of lowland rain forest. However, all of these
range beyond the limits of lowland rain forest. To varying degrees
A. aqiiaticus, A. biporcatiis, A. carpenteri, A. capita, A. limijrons,
and A. polylepis (in about that order) extend to increasingly higher
elevations in subtropical forest, and there overlap the next group of
species, A. imignis, A. intermeditis, and A. tvoocli. A humilis and
A. lionotus are even less restricted and they extend into montane
cloud forest, overlapping A. tropidolepis there. A. tropidolepis is
the most deviant species; seemingly because of tolerance for low
temperature, it occurs mainly beyond the altitudinal limits of other
species, and even where there is some overlapping, competition
with other anoles must be slight.

Column 2 of Table 8 shows the most typical situation for anoles
of each species, disregarding variation due to sex, size, season, and
geographical area. For eight species tree trunks near the ground
are the most frequent choice; prey is taken from the ground at the
base of the tree and the animal is confined to a small area with
tree-trunk-to-ground orientation. The eight species, A. polylepis, A.
tropidolepis, A. sericeus, A. limijrons, A. carpenteri, A. capita, A.
limifrons, and A. intermedins are judged to be increasingly tree
oriented, in about that order. A second group of species, A. insignis,
A. pentaprion, and A. woodi, are arboreal and relatively independ-
ent of the ground surface. A. biparcatus and A. insignis are the
most arboreal, whereas A. woodi is usually found on trunks within
a few meters of the ground and A. pentaprion has been found in
relatively small trees, less than 0.5 m in trunk diameter. Deviating
in the opposite direction, A. cupreus, and especially A. humilis, are
largely ground-living, though they may climb on tree trunks or
stems. A. aqiiaticus and A. lionotus deviate most from typical anoles
in habitat by being semi-aquatic. Withal, the 16 species variously
overlap one another in aspects of structural habitat, and overlap in
an important component of habitat, perch height, has been exam-
ined in Table 6.

Preferred body temperatures (summarized in column 3 in Table
8) of the 16 species fall into three fairly distinct groups. Eight
species are usually in the temperature range of 26-28 — a fairly typi-
cal daytime air temperature for tropical rain forest. Seven of the
species are those of rain forest; the remaining one, A. intermedins,
occurs in higher and cooler areas, but basks. In the second group
the five species, adapted to lower temperatures, between 19.5 and
24, are all nonbaskers, living in deep shade of forest floor, or in wet
places or at high elevations. At the opposite extreme are three spe-
cies, A. cupreus, A. pentaprion, and A. sericeus, which have rela-
tively high temperatures, often above 31; all have some heliophilic
tendencies. At the upper edge of its altitudinal range A. cupreus

54 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

Taule 7. — A. (Upper bight), estimated ovehlap in body temperature uetweex species. — — little or no overlap, + = moderate
(ivfil.ip, ++ = extensive or complete o\erlap.

B. (Lower leet), estimated c;eoghaphic overlap between species within Costa Rica. — = none, + = up to !i of occupied
area, -\ — h = Ji to 3 of occupied area, + + + — /4 to all of occnpied area. In each double set of symbols those of the upper row refer li
range of the species listed in tlie horizontal column at top of table, and those of the lower row refer to species listed in the vertical
column at left.

5"

1

c

■c

a;

'2

S

5

c
.2

c

o
T
C

C
o

&

>.

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(A

1

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0

c

aquaticus

\ \

L +

+

+

-

++

++

+ +

+

+

+

-

+

-

++

++

biporcatus

-

\\

+ +

+ +

-1-

-1-

+

+ +

++

+ +

+ +

+

+ +

+

+

+

capito

++
+

+++
++

\:\

+ +

-1-

+

-U

+ +

++

+ +

+ +

4-

+ +

+

-1-

X

carpenteri

-

+++
+++

++
++

+

+

+

+ +

++

+ +

+ +

-l-

+ +

_L

4,
1

-;-

cupreus

—

-

-

-

\\^

-

-

4-

+

+

+

+ +

+

+ +

-

-

humilis

+

+

+++
++

+++
++

+ + +
-1-

N,

\\

-!- +

4-

+

+

.1.

-

+

-

-(--4.

1

iiisignis

-

-

-

-

-

+
+ +

\

k +

+

H-

+

-

+

-

+-I-

-I--I- ;

intermedins

-

-

~

—

+

+
+

+ +
+ +

\^+

++

+ +

-,-

+ +

-1-

.1-

+

Icmurinus

+
+

+++
++

++
++

+ + +

+

—

+++

+ +

—

—

x^

I ++

+ +

+

+ -1-

+

4-

limifrons

+
+

+++

-r +

++

++

++ +

-1-

-1-

++ +
+ -I-

—

—

+++
++

^

+ +

-"

-IH-

-1-

-1-

"t"

lioiiotus

+

+ + +

++

+ + +

+

+ +

4-

-1-

+++

+++

\\

_l .

+ +

-U

+

+

+

+ +

++

+

4-

+ -i-

—

4-

++

+ +

\^^

pentaprion

-

+ + ■1-
+ +

++
+

4-

+ + +
+ +

.l_

-

-

++

+ +
+ +

+ + +
+ + +

+

+ -h

—

—

polylepis

++
+

-

++

++

-

-

+

-

-

+

++

+

++

+
-\ +

-I- +

\^

+

4_

sericeus

—

—

+

_

+ -I-

—

—

—

—

+

+

■f +

—

\ ^

[ -

-

+

+ -!■

++

+ +

+ + +

\^

\^ ;

tropidolepis

—

—

—

—

—

+
+ +

-1-
+

+
-I- +

—

—

—

+

-4

~

—

\X++

woodi

—

"

+
+ +

+
+ +

+
+ +

+
+

-

\:

averages several degrees below the temperatures it maintains at low
elevations.

As regards sexual difference in size (columns 4 and 5 of Table
8) there are three, approximately equal groups of species: A.
aquaticus, A. lionotiis, A. pentaprion, A. polylepis, and A. sericeus,
in which the male is markedly larger; A. biporcatus, A. insignis, A.
intermedius, A. tropidolepis, and A. woodi, in which the sexes are
approximately equal (but with males definitely larger in the first
three); and A. capito, A. carpenteri, A. humilis, A. lemnrinus, and
A. limifrom, in which the female is larger. Size disparity is greatest
in A. cupreus, in which the male is (linearly) 13% larger than the

COSTA RICAN ANGLES

55

female. However, differences of this magnitude or even greater
(always with the male larger) are common in the insular West
Indian species.

There are eight species having a large, brightly-colored dewlap
(column 6 of Table S) in the males and no dewlap, or only a rudi-
ment, in the female. In three other species, A. interniedhis, A.
limifwns and A. icoodi, the male dewlap lacks bright colors, and
in both A. limifrons and A. intermedins it is relatively small.

In A. capita the dewlap is especially small, and this, together
with the fact that the female is 10 per cent larger than the male, sug-
gests that social relationships are somewhat different from those in
other species. While correlation between development of dewlap
and development of territoriality has not yet been demonstrated,
some relationship seems probable because the dewlap functions
mainly in aggressive display. Species in which aggressive display
is important in intimidating rivals or maintaining territories would
through natural selection be more likely to develop a large and color-
ful dewlap than would those species in which display and combat
behavior were weakly developed or absent. In A. biporcattis, A.
imignis, A. lemurimis, and A. pentaprion the dewlap is present and
colorful in both sexes, but always is larger in the male. In A. le-
murimis the female's dewlap is only 23% of the male's area, but in
the other three the male and female dewlaps are more nearly cfiual.
These four species have in common medium to large size, and all

30

40 50

SNOUT VENT

60
LENGTH:

70 80

MILLIMETERS

Fig. 4. — Histogram showing approximate mean adult sizes of \'arious spe-
cies of native Costa Rican anoles and extent of size overlap with sympatric
and neighboring species. Anolis insignis, not included, is much larger and does
not overlap any others.

56

OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

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COSTA RICAN ANGLES 57

of them except A. lemurinus are highly arboreal. It may be specu-
lated that in these species having well-developed female dewlaps
there is some degree of territoriality in females, beyond that found
in the smaller, tree- trunk-to -ground-oriented species.

In adult size (Fig. 3), the species other than A. insignis form a
continuum from a minimum of 30 mm up to a little more than 100
mm, with the species-average 57.1 for males and 56.5 for females.
Seven species are in the range 40 to 69 mm and five are in the range
70 to 99, while the three smallest species, A. carpenteri, A. humilis,
and A. limifrons, all average less than 40 mm. A. insignis is much
larger than any of the other 15, with no overlapping.

A. polylepis is perhaps the most typical, or generalized anole
species of the entire group, as it conforms to the mode in all six of
the ecological and morphological traits used in Table 8. Other spe-
cies that conform best with the modal type (in four of the six
categories for each) are A. carpenteri, A. lemurinus, A. lionotus,
and A. sericeus. Those that conform least well to the mode ( by only
one criterion or none) are A. insignis, A. ivoocli, and A. pentaprion.

In summation, it appears that the selective pressure generated
by co-occurrence of many similar species may favor change in vari-
ous directions away from a generalized ecologic and morphologic
"type" that is near the mode. Some of the commonest patterns of
change are : ( 1 ) Dwarfing, or the opposite of marked increase in
size (in extreme cases gigantism may permit predation on the
smaller species, which no longer offer competition for food, except
perhaps to the juveniles). (2) Alteration of normal size relationship
between the sexes of a species, to permit one sex to occupy a size
category not filled by other local anoles. (3) Adaptation to a special
habitat, such as tree-top, bark, lichen, low herb, leaf litter, rock or
stream edge. (4) Adaptation to physically rigorous conditions of
high montane areas or xeric situations or to semi-aquatic conditions.
There is a trend of decreasing numbers of species, from the many
that approximate the modal type to the few that conform to any
of these major specializations.

Acknowledgments

Dr. and Mrs. Anthony A. Echelle and Dr. Robert R. Fleet
helped me in the field. Dr. and Mrs. Richard K. LaVal obtained
many of the records and specimens at Monte\'erde and Finca La
Selva. Wayne Van Devender and James Talbot also contributed
specimens and records from Finca La Selva. Dr. Paul B. Robertson
kindly made available his notes with field observations on Anolis
capita at Rincon de Osa. Jorge Campabadal of the Organization
for Tropical Studies' San Jose Office extended many courtesies in
permitting use of O.T.S. facilities. Financial support from tlie Uni-
versity of Kansas (General Research Grant 3344-5038), and the

58 OCCASIONAL PAPERS MUSEUM OF NATURAL HISTORY

National Science Foundation (GB 6724) is gratefuly acknowledged.
Dr. Robin M. Andrews contributed helpful suggestions and ideas.

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COSTA RICAN ANGLES 59

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