The normal breeding season and gestation period of martens

HARVARD UNIVERSITY.

LIBRARY
OF THE

MUSEUM OF COMPARATIVE ZOOLOGY

13,664
t Ae Lo “woe

Wo

<

oa 1130

MAR8 1930 f3

CIRCULAR No. 107 FEBRUARY, 1930

UNITED STATES DEPARTMENT OF AGRICULTURE
WASHINGTON, D. C.

3.367
‘THE NORMAL BREEDING SEASON AND GESTATION
PERIOD OF MARTENS

By Franx G. AsHBrook, Principal Biologist, in Charge Diwision of Fur Re-
sources, and Kart B. Hanson, Biologist, Director of United States Fur-Animal
Experiment Station, Bureau of Biological Survey

CONTENTS
Page Page
SE eee ee 1 | General breeding habits of martens_________- 4
Beginning of experiments-_--_------- . 1 | Research in other countries_______________.- 5
@xperuments of 1928_-______----------------_ “| SU SS oe =k Se eee eee ee 6
INTRODUCTION

In 1913, the Bureau of Biological Survey started preliminary
breeding experiments with martens (Martes americana) at Pritch-
ard, Idaho. When the fur farm at that place was abandoned in
1915, the martens were shipped to Washington, D. C., where for a
_ short time they were kept in the National Zoological Park. After

the establishment of the bureau’s experimental fur farm in the foot-
hills of the Adirondack Mountains near Keeseville, N. Y., 6 martens
were shipped from Washington in August, 1916. At the end of
January, 1917, 4 additional martens were obtained, making a total
of 10 breeding animals under observation. Six of these martens
were lost between the breeding season of 1917 and that of 1918—
3 died from disease and 2 from injuries, and 1 escaped. The breed-
ing stock for the year 1918 was thus reduced to 4 animals.
Until the spring of 1920 the males were not allowed to run with
_ the females, except during January, February, and the early part
- of March, which had been considered the breeding period. Na
young were produced during the eight years from 19138 to 1920.

BEGINNING OF EXPERIMENTS

During the fall of 1919 and the spring of 1920, considerable diffi-
culty was experienced in keeping the males and females separated,
because they frequently burrowed under the carpet wire. They
mingled considerably that fall and in the winter of 1919-20, and
it was observed that they seemed to live together harmoniously.
This observation differs from those of A. H. Cocks,! who had con-
ducted experiments with martens in England. Mr. Cocks and many
other naturalists have reported that martens do not live happily

1Cocks, A. H. NOTD ON THD GHSTATION OF THB PINE-MARTEN. Proc. Zool. Soc. London
1900 : 836-537. 1900.
89748°—30 cf.

2 CIRCULAR 107, U. S. DEPARTMENT OF AGRICULTURE

together and will destroy one another if both sexes are put in the
same pen when the female is not in heat. }

A general belief had prevailed that the only time of year that
male martens could be permitted to live with females was during
the months of January and February. Since this was found not
to be the case at the United States Fur-Animal Experiment Station,
it was decided to allow the males to run with the females during all
seasons of the year, except in spring, when the young are born.
The martens were pechonably tame, well fed, and in an apparently
healthy condition. It was natural, therefore, to expect that they
would mate and produce young. Some consideration of this problem
led to the theory that conalbly martens in captivity breed at an-
other period of the year than do those in the wild, the commonly
accepted opinion being that in the wild they mate in January or
February. If this were true, the explanation of the fact that there
were no matings and no young born at the experiment station would
be that the two sexes were not allowed to run together at the proper
time.

On May 10, 1920, the males were turned in with the females. They
lived together in a friendly manner until the latter part of July
and the early part of August. About this time they squealed con-
siderably and it was noted that one of the females had received a
severe injury to one ear. It was suspected that the martens were ,
fighting, and separating the sexes was considered. Early on the
morning of August 13, 1920, the martens were making so much
noise that the caretaker made a special visit to the pens and saw
one pair mate; observations later in the day revealed this as the
cause of the peculiar noise.

The male that had been seen to mate had a tumorlike growth of
the sheath, which it was thought might interfere with service. An-
other male was therefore introduced, and this one also was seen to
serve several times. The next day it was removed and the first one |
returned. When this male first entered the pen, he failed to notice
the female, which was on the ceiling wire, but as soon as he discov-
ered her, he ran up, seized her by the nape of the neck, and carried
her down to the ground and served her. This female was seen to
mate on several occasions in the four days from August 13 to 16.

On August 26, 1920, the females were put in separate pens and
kept there until the latter part of November, when they were again
turned in with the males and animals of both sexes allowed to run
together until April 4, 1921. They were then separated again.

The female that was seen to mate during August, 1920, appeared
to take on considerable weight from one to two months afterwards.
She gave birth to a litter of three on April 15, 1921. When the
nest box was examined one of the young appeared to be dead, but it
was not removed because the female was extremely nervous and
excited. The next time the nest box was opened, only two young
could be found. There was no trace of the third. Since the mother
was very nervous and prone to carry the young roughly about the
pen whenever someone went near the den, it was deemed advisable
to disturb her and her litter as little as possible until the young
were about a month old. This female hac been in captivity since
December, 1917, without producing any young, even though every

BREEDING SEASON AND GESTATION PERIOD OF MARTENS 3

year she had been allowed to run with a male throughout January
and February.

During the summer of 1921 it was planned to keep the martens
under close observation to note matings and then to segregate the
mated females until late in the spring of the following year. Con-
ditions were not satisfactory, however, for carrying out these plans.
Since no matings were observed that summer, the males were allowed
to run with the females from July 13, 1921, to April 1, 1922. Al-
though no matings were observed during this period, the same mar-
ten that produced and reared the litter in 1921 gave birth to three
female young on April 16, 1922.

During the summer of 1922 the males were turned in with the fe-
males each morning, but at night they were kept in separate pens,
in order to avoid the possibility of unobserved matings taking place
at night. When the females came into heat, the males sometimes
served them immediately after they were turned in in the morning,
and usually within an hour after admission, often in spite of the im-
mediate presence of observers. All three males used in these ex-
periments proved to be polygamous.

The old female that had produced the two litters previously men-
tioned was seen to accept service several times between July 28 and
August 6, of that year, as did also one of the young females, less
than 4 months old, several times between August 4 and 19, as well
as on September 3, though not betweer August 19 and September 3.
Both of the litter mates of this younger animal were seen to mate
on August 6.

The females were separated from tle males on September 10, 1922,
and kept in pens by themselves until July, 1923, in order to deter-
mine whether the gestation period was approximately 8 months, as
the aforementioned observations indicated. In January, 1923, two of
the four females that had mated during the previous summer died, but
no evidences of pregnancy were noted in either. One was the animal
that had reared the two litters, and the other was a young female
born in the spring of 1922. The other two females, both of which
were seen to mate during the previous summer, failed to produce
young in the spring of 1923.

In 1923 there were three female and three male martens. All three
females were seen to mate during August, 1923. These were sep-
arated from the males in September, as in the year before, but no
young were produced. Late in the fall of 1923, the martens were
moved to the new fur-animal experiment station of the Biological
Survey at Saratoga Springs, N. Y.

There were only 3 females and 2 males left in the summer of 1924.
One of the females was killed within a few hours after it was
placed in a pen with another female. The 2 remaining females both
showed signs of heat in August, but only 1 was seen to mate. Both
males were about 10 years old and showed indications that their
usefulness was at an end. No young were born in the spring of 1925.

Both females mated during August, 1925, but no young resulted
the following spring. One of the two females on hand in the summer
of 1926 was seen to mate during August. Each of the two females
was allowed to run with a male throughout the summer and winter
months, but neither produced young in the spring of 1927.

4 CIRCULAR 107, U. S. DEPARTMENT OF AGRICULTURE

On April 6, 1927, a female that was trapped in the wild during
the latter part of December, 1926, gave birth to a litter of three
young, two of which were reared to maturity. This female had
access to a male only a few hours every other day during the last
three weeks of February, but it is not believed that she mated at
any of these times, as it was observed that she would not tolerate
the presence of the male. When he attempted to enter her pen, she
imvariably drove him back to his own. The indications were that
this female mated in the wild some time before she was trapped.’

In the summer of 1927 there were 4 adult females and 4 adult
males, and 2 young martens, one male, the other female. All but 1
of the 4 adult females were seen to mate in August, 1927. The
female that had weaned her young just a short time before refused to
tolerate the presence of a male. As during the previous winter, she
invariably drove the male out when he entered her pen. Although
the males were allowed to run with the females from early in July
until the end of February, no young were born in the spring of 1928.

EXPERIMENTS OF 1928

During the summer of 1928 the marten stock consisted of 13 adult
animals, 7 females and 6 males. Six of the seven females were seen
to mate between July 11 and August 12, most of them several times.
On July 19 one of the males killed the mate he had served on July 11,
and a little later it was decided not to use him again that season,
as he proved too rough and vicious when with the females. The
males were kept in separate pens at night and allowed to run with the
females during the daytime only, to facilitate better observation of
matings. On September 4, 1928, all the females were separated from
the males and placed in pens by themselves until early in the summer
of 1929. On April 23, 1929, one of the females that mated on July 22
and 23 and August 6 and 7, 1928, gave birth to a litter of young,
although she had not been with a male since September 4, 1928.
This finding demonstrated conclusively that the summer matings
resulted in conception and that the gestation period ranged from
259 to 275 days or from 814 to 9 months. (It was not known from
which mating the female conceived.) ;

GENERAL BREEDING HABITS OF MARTENS

In these experiments it was found that the male and female mar-
tens usually live together agreeably during most seasons of the year.
Occasionally some of the females seemed partial to certain males,
especially to those with which they had been allowed to run for some
time prior to the oestrum. During the first week or so of the post-
oestrual period the male may be inclined to annoy the female, as is
noted by the antagonistic attitude she assumes toward him. Before
long, however, he discontinues attempts to mate.

ale martens usually fight ferociously whenever they come in
contact ; the same seems to be true of females.

*ASHBROOK, F. G., and HANSON, K. B. PROGRESS REPORT OF MARTEN BREBDING EXPERI-
MENTS, U. 8S. Dept. Agr. Biol. Surv. Leaflet Bi-949, 5 p. [mimeographed], November,
1927: and BREEDING MARTENS IN Captiviry, Journ. Heredity 18 (11) : 499-503, illus.,
November, 1927.

‘BREEDING SEASON AND GESTATION PERIOD OF MARTENS 5

_ In many females there are two periods of two or three days each
uring which they will accept service. These two periods are usually

_ from one to two weeks apart.
During the oestrual period the female frequently makes a clucking
noise entirely different from that made at other times, apparently a
call to attract the male. She squats and urinates frequently, espe-
cially on stones and other objects in the pens, and climbs and mounts
the male when he is apparently passive. Quite often she switches her
tail nervously and wrestles with him considerably, though squealing
loudly when he treats her too roughly. When she does not accept
service readily, the male will chase and struggle with her until

mating is accomplished. :

The question has arisen in connection with these experiments with
martens whether the fertilized ovum may lie in a dormant state for
several months before noticeable embryonic development begins, as
in the roe deer. Williams®* in discussing the duration of pregnancy
in wild animals, states:

Harms notes the peculiar fact that in the deer there is a period of 40 weeks
between fertilization and the birth of the young, but that this time does not
represent the period of development of the fetus as we understand it in most

animals. The ovum of the deer undergoes segmentation and then lies in the
uterus for 4 months in an essentially dormant state. About December the dis-
tinctive embryonic development begins, and birth follows in May or June—
about 5 months later. * * * It is suggested that this delay in the develop-
ment of the young is a provision by which it may be born at a favorable season
of the year.
Apparently the same condition obtains with martens, as females
trapped and killed in the wild have not shown macroscopic signs of
pregnancy until late in winter.

RESEARCH IN OTHER COUNTRIES

Heinrich Prell, of Munchen, Germany, after a visit to the United
States during the winter of 1927 for. the purpose of studying fur-
farming developments, wrote the Biological Survey as follows:

One of our German breeders on my advice has kept together a pair of stone
martens. On July 16 he observed a mating at about 9 o’clock in the morning
and again about 5 in the evening. A forester observed a pair of martens
mating at about 4 o’clock in the morning. These two observations may prove

that the European marten [Martes foina] has the same biology as the American
marten,

On advice from Doctor Prell, H. Reinhardt conducted experiments
with stone martens. He observed matings on July 16, 1927, July
5, 6, and 7, 1928, and on June 28, 1929. The first young were born on
April 7, 1929. The information contained in Doctor Reinhardt’s
canes | is almost identical with our observations in the United

tates,

V. Generosoff, of Leningrad, Russia, in a letter to the Biological
Survey states:

Your discovery of ‘the breeding period of American martens leads me to
believe that the same is true of our sables [Martes zibellina] * * *. This

® WILLIAMS, W. L. VETERINARY OBSTETRICS, p. 169. Ithaca, N. Y. 1917.
“REINHARDT, H. BEITRAG ZUR ZUCHT UND JUGHNDENTWICKLUNG DES STEINMARDERS.
-Dentsche Pelztierzuchter No. 15: 445-448. Munchen. 1929.

6 CIRCULAR 107, U. 8S. DEPARTMENT OF AGRICULTURE

year (1929) litters were received on two sable and fox farms; also a sabie
gave birth to three young ones, which were successfully raised to maturity. It
is my personal opinion that investigations of sable farming were promoted
by your marten-breeding experiments, and for that my countrymen are indebted
to you.

SUMMARY

The normal breeding season in martens occurs during the summer
months, usually between the middle of July and the third week in
August, and not during the winter months.

From these experiments it has been definitely determined that the
gestation period ranges from approximately 814 to 9 months (259 to
275 days); instead of 60 to 102 days as has been heretofore generally
accepted to be the case.

ORGANIZATION OF THE
UNITED STATES DEPARTMENT OF AGRICULTURE

February 6, 19390

Secretary of Agriculture—..-.-----~.__-.—-- ArgrHur M. Hype
Assistant Secretary————- _-* =. R. W. DUNLAP.
Director of Scientific Work_—-_------—------. A. F. Woops.
Director of Regulatory Work__--------_----- Watter G. CAMPBELL.
Mirector of Extension Work=-—_.--__=._____- C. W. WARBURTON.

Direction of Personnel and Business Admin- W. W. STocKBERGER.
istration.

tpmeceior of information=_—- == M. S. EISENHOWER.

(0 TUNG aS SR ARS a el a oa ne E. L. MARSHALL.

UE NERA a ee ee eee CuHarRLEs F. Marvin, Chief.

Bureau of Animal Industry_____-_______-__-. JoHN R. MoHLER, Chief.

Bureau, of Dairy Indusiry__-———_______.___. O. E. ReeEp, Chief.

Burcawof Plant Industry____-_—___-—____.=_ Wriruram A. Tayzor, Chief.

OES se Bee. . SE ee eee ee R. ¥. Stuart, Chief.

Bureau of Chemistry and Soils_____________~ H. G. Knieut, Chief.

Bureau of Entomology___________- oe! ee C. L. Magxatt, Chief.

Bureau of Biological Survey________________. Paut G. Repincton, Chief.

Burcav of; Pubiie Roads__—-..---_---__.- Tuomas H. MacDonaLp, Chief.

Bureau of Agricultural Economics__________— Nits A. OLSEN, Chief.

Bureau of Home Economics_______-_________ LOUISE STANLEY, Chief.

Piant Quarantine and Control Administration_. Lee A. Strone, Chief.

Grain Futures Administration___________-_.___ J. W. 'T. Duven, Chief.

Food, Drug, ond Insecticide Administration___ WATER G. CAMPBELL, Director of
Regulatory Work, in Charge.

Office of Experiment Stations_______________. ———_—_,, Chief.

Office of Cooperative Extension Work_______- C. B. Smiru, Chief.

LUT ase Se eee CLARIBEL R. BARNETT, Librarian.

This circular is a contribution from

Bureaw of Biological Survey______------~-- PauL G, Rsprneton, Chief.
Division of Fur Resources_______-----~~- Frank G. ASHBROOK, Principal
Biologist in Charge.
7

U.S. GOVERNMENT PRINTING OFFICE: 1930

For sale by the Superintendent of Documents, Washington, D. C. - - - - - - Price 5 cents

iN II

PUG): ote Mm PWR
" re) ee tas Wi :