112 THE HISTORY OP ANIMALS. [iJ. V. 



others have none upon their under side, or less than on 

 their upper side, but the change of the voice is conspicuous 

 in some of them. And in others different parts of the body 

 signify the period of the formation of the semen, and of the 

 power of reproduction. 



3. In almost all animals the voice of the female and of 

 the young is more acute than that of the male and the older 

 animals, for even the stags have a deeper voice than their 

 females. The males utter their cry at the season of copula- 

 tion, the females when they are alarmed. The voice of the 

 female is short, that of the male longer. And the barking ot 

 old dogs is also deeper than of young ones, and the voice of 

 the horse also varies. The females utter a little small cry 

 as soon as they are born, and the males do the same, but 

 their voice is deeper than that of the female, and as they 

 grtfvv older, it still increases. When they are two years 

 old, and reach puberty, the male utters a great deep voice, 

 that of the female is greater and clearer than it was at first ; 

 this continues till they are twenty years old at the outside, 

 and after that the voice, both of the male and female, be- 

 comes weaker. 



4. For the most part, then, as we observed, the voice of 

 the male differs from that of the female in depth, in those 

 animals which utter a lengthened sound. There are, how- 

 ever, some exceptions, as oxen; for in these animals the 

 voice of the female is deeper than that of the male, and the 

 voice of the calf than that of the full-grown animal ; where- 

 fore also in the castrated animals, the voice changes the 

 other way, for it becomes more like that of the female. 



5. The following are the ages at which animals acquire 

 the power of reproduction. The sheep and goat arrive at 

 puberty within a year after they are born, and especially 

 the goat, and the males as well as the females, but the off- 

 spring of these males and of the others is different. 

 Eor the males are better the second year than when they 

 become older. In hogs, the male and female unite at eight 

 months old, and the female produces her young when she is 

 a year old, for this agrees with the period of gestation. 

 The male reaches puberty at eight months old, but his off- 

 spring are useless till he is a year old. But these periods, 

 as we have said, are not always the same, for swine will 



