THE (ESTROUS CYCLE IN THE MAMMALIA 57 



or two annual breeding seasons. The probability is that there 

 is only one (in March), the young being born in May ; but Millais 

 records that he has seen young wild cats, which could not have 

 been more than forty days old, killed in Scotland in October. 

 Cocks, in a letter quoted by Millais, says that he has received 

 wild cats which, judging from their size, were probably born in 

 August or September, and that in captivity he has observed a 

 female experience " heat " during the summer. " Many years, 

 when owing to the death, of the young, or the fact that the pair 

 had not bred together in the spring, I have kept male and 

 female together all summer, but they showed no inchnation to 

 breed." In a more recent letter to the author Mr. Cocks states 

 that the old female wild cat in his possession came " in season " 

 and received the male in the autumn of 1904, after the death 

 of the kittens which were born earher in the same year. The 

 animal, however, failed to become pregnant. In the experience 

 of this observer the commonest month for wild kittens is May, 

 but the range of dates in his collection varies from April 20 

 to July 22. The period of gestation was ascertained to be 

 sixty-eight days. The period of oestrus was observed to last for 

 five days, or about the same time as in the domestic cat. 



The male wild cat has a definite season of rut (hke the stag), 

 and caUs loudly and incessantly, making far more noise than 

 the female cat.^ This information is interesting, since the 

 males of most Carnivora, so far as is known, do not experience 

 anything of the nature of 'a recurrent rutting season, although 

 many individuals show indication of increased sexual activity 

 at some times more than at others. So far as I am aware, 

 nothing of the nature of a rutting season is ever known in the 

 males of the domestic cat, dog, or ferret, all of which seem to 

 be capable of coition at any period of the year. On the other 

 hand, the males of certain seals appear to possess a season of 

 rut at the same time as the sexual season in the females. 



Little is known definitely regarding the breeding habits of 

 the larger Felidse in their wild state, beyond the fact that they 

 probably agree in having a single annual sexual season. In 

 captivity certain of them, at any rate, are polyoestrous. Thus, 



1 I am indebted to Mr. Cooks for information regarding the breeding 

 habits of the wild cat. 



