THE "sexual season" OF MAMMALS. 13 



female, the general scheme of his reproductive period, and 

 breeding, sexual or rutting season, remains the same. 



The Breeding Season of Female Mammals. 



The breeding season of mammals should rightly be con- 

 sidered after the sexual season has been discussed, but, 

 owing to the fact that the term " breeding season " has been 

 so universally used to designate the sexual season as well 

 as the gestation period of breeding mammals, it is necessary 

 to say a few words here in order to make the following 

 account clear. 



The occurrence of a breeding season depends upon the 

 occuiTence of a sexual season, and those factors which 

 influence the former, influence also the latter, and will be 

 treated under that head. The same is true for the recurrence 

 of both the breeding and the sexual seasons. 



The recurrence of the sexual season may be interfered with 

 by the bearing of young, both gestation and nursing may 

 so interfere, but that does not remove a consideration of the 

 question, under such circumstances, out of the realm of the 

 sexual season ; the effect of these processes, of bearing youug 

 and of nursing young, on the sexual season, must be con- 

 sidered in relation to that period, and must not be supposed to 

 have relation only to the remainder of the breeding season. 



Questions regarding the breeding season of mammals con- 

 cern what happens during both the sexual and the gestation 

 periods jointly, and, as I have before stated, the expression is 

 a term used to define the period passed through by an animal 

 which experiences both these processes ; it is not applicable as 

 an expression or term which may be used for the occurrence 

 of either of them separately, nor for the effect one of these 

 processes may have upon the other. 



A breeding season may include only one sexual season and 

 one gestation period ; this is true for all moncestrous mam- 

 mals, of which the bitch will serve as an example, and it may 



