48 THE PHYSIOLOGY OF REPRODUCTION 



several antelopes are all probably monoestrous in the wild state. 

 This is rendered not unhkely from the limited sexual and calving 

 seasons which these animals are known to experience, but it is 

 by no means certain. " The American bison experiences a 

 sexual season from some time in July until some time in August. 

 [Cathn says August and September are the months when they 

 breed ; see below.] In the Cashmir ibex it persists during 

 parts of November and December. In the markhor and 

 Hemitragus jerulaicus in Cashmir it occurs in December, while 

 in the barasingha in that country, from September 20th to 

 November 20th, it has been observed. ... In Scotland the red- 

 deer's sexual season lasts three weeks, during September and 

 October, according to Cameron ; ^ while in this country [England] 

 September is the sexual month for the fallow-deer,^ and July 

 and August the time when the roe-deer will receive the male. 



" In all these cases there can be httle over three weeks 

 during which copulation takes place, and the extremely Umited 

 period during which parturition occurs strongly corroborates 

 the view that this is the extent of the usual time during which 

 sexual intercourse is possible. The fact that in captivity three 

 weeks is the usual period which intervenes between two cestri 

 in such animals, and the extreme probability that individual 

 females do not experience oestrus at exactly the same time, 

 predispose one to beheve that they are monoestrous in the wild 



buck in July 1862, gave birth each to two young in the following May. It 

 would appear probable, therefore, that the ovum lies dormant during the 

 early months of gestation. Grohmann suggests that the " false rut " in 

 November may have a quickening influence on the ovum, and so cause it 

 to develop. 



1 Millais says (vol. iii. 1906) that the actual time of rut depends much on 

 the season. September 28, in Scotland, is called " the day of roaring." Sir 

 S. M. Wilson {Field, October 8, 1904), however, reports a case of a stag which 

 roared during the whole summer in Kinveachy Forest, Boat of Garten, in 

 1904. Stags eat little or nothing during the rutting season, and lose weight 

 rapidly. During the first days of roaring they are said to suck up a mixture 

 of peat and water (Millais, loc. eit.). 



^ Millais says (loc. cit ) that the fallow-deer in England ruts in October. 

 The necks of the big bucks swell greatly during the iirst week, and the 

 animals become more and more unsettled until about the 25th, when the first 

 calls are heard. The actual rut is short as a rule. The doe drops her calf 

 about the beginning of June, and rarely two or three are born at a time. 

 Sometimes, however, the females may come in season at irregular times, and 

 drop calves in any of the months after June and even as late as November. 



