44 THE PHYSIOLOGY OF REPRODUCTION 



are all probably moncestrous in the wild state. This is rendered not 

 vinlikely from the limited sexual and calving seasons which these 

 animals are known to experience, but it is by no means cei-tain. 

 " The American bison experiences a sexual season from some time 

 in July until some time in August. [Catlin 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 Hemitragxm jerulaicus in Cashmir it occurs in 

 December, while in the barasingha in that country, from 20th 

 September to 20th November, 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 thei fallow-deer,^ and July and 

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



" In all these cases there can be little over three weeks during 

 which copulation takes place, and the extremely limited 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 oestri in such 

 animals, and the exti'cme probability that individual females do 

 not experience oestrus at exactly the same time, predispose one to 

 believe that they are monoestrous in the wild state ; but, if the 

 limit of time for coition is three weeks, there is still just time for 

 the females to undergo two dioestrous cycles, and it is this possibility 

 which prevents positive assertion on the matter. 



des Rehes, Giessen, 1854) rut occurs in early autumn, but the embryo is not 

 developed beyond the stage of segmentation in the following spring. Grohmann 

 (Sport in the Alps, Edinburgh, 1904) says that rut is experienced in July 

 and the beginning of August, but that there is a "false rut" in November. 

 Observations on roe-deer in Vienna showed that the period of gestation is 

 ten months ; for seven females which were served by one 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. 



^ 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 Eorest, 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. oit.). 



" Millais says {loc. cit.) that the fallow-deer in England ruts in October. 

 The necks of the big bucks swell greatly during the first 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. 



