BREEDING SEASON AXD GESTATION PERIOD OP MARTENS 3 



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

 and February. 



During the s umm er 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 }'ear, 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 between August 19 and September 3. 

 Both of the litter mates of this younger animal were seen to mate 

 on August 6. 



Tbe females were separated from the 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 m^.les 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 3'oung 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. 



