260 



CALIFORNIA FISH AND GAME 



BREEDING SEASON AND PERIOD OF GESTATION 



According to my observations, which have extended over many 

 seasons, the period of gestation in the mule deer is about seven months 

 (205 to 212 days). 



In 1927, the first actual copulation that I was able to discover 

 in deer in Yosemite took place on December 10. I had been watching 

 the deer daily from the sixth of December, so had actual mating taken 

 place during the daytime I would have had a fair chance to notice it. 



The following season, the first fawns that I was able to find were 

 born at noon on the ninth day of July, 1928. In 1928, the earliest 

 observed actual breeding among deer took place on December 2. The 

 earliest fawns observed the following season were born on June 30. 



Fig. 98. Does far advanced in pregnancy, as here shown, are more seaate and 

 do not bound wildly about as at other seasons. Yosemite, July 10, 1928. Mus. 

 Vert. Zool. No. 57 49. 



The most definite data that I have been able to secure on the 

 period of gestation of the Rocky Mountain mule deer in California has 

 been obtained through the kindly interest of U. S. Forest Ranger Oscar 

 L. Barnum. In a letter of February 15, 1931, Barnum states : 



"Mr. J, W. Stiner of Cedarville, California, has had three pet 

 female mule deer at his place, and he has kept an accurate record of the 

 date when these deer mated and he also set down the dates when the 

 fawns which resulted from these matings were born. 'Fleet,' the old 

 doe, bred December 21, 1927, and gave birth to twin female fawns on 

 July 17, 1928. In 1928 she took the buck on December 24, and gave 

 birth on July 19, 1929, to twin fawns. In 1929, she bred December 23, 



