132 STERILITY FROM Chap. XVIII. 



different menageries would differ. Indeed, some animals in 

 our Zoological Gardens have become more productive since 

 the year 1846. It is, also, manifest from F. Cuvier's account 

 of the Jardin des Plantes, 11 that the animals formerly bred 

 much less freely there than with us ; for instance, in the 

 Duck tribe, which is highly prolific, only one species had at 

 that period produced young. 



The most remarkable cases, however, are afforded by animals 

 kept in their native country, which, though perfectly tamed, quite 

 healthy, and allowed some freedom, are absolutely incapable of 

 breeding. Rengger, 1 * who in Paraguay particularly attended to 

 this subject, specifies six quadrupeds in this condition; and he 

 mentions two or three others which most rarely breed. Mr. Bates, 

 in his admirable work on the Amazons, strongly insists on similar 

 cases ; 13 and he remarks, that the fact of thoroughly tamed native 

 mammals and birds not breeding when kept by the Indians, cannot 

 be wholly accounted for by their negligence or indifference, for 

 the turkey and fowl are kept and bred by various remote tribes. 

 In almost every part of the world — for instance, in the interior of 

 Africa, and in several of the Polynesian islands — the natives are 

 extremely fond of taming the indigenous quadrupeds and birds; 

 but they rarely or never succeed in getting them to breed. 



The most notorious case of an animal not breeding in captivity 

 is that of the elephant. Elephants are kept in large numbers in 

 their native Indian home, live to old age, and are vigorous enough 

 for the severest labour ; yet, with a very few exceptions, they have 

 never been known even to couple, though both males and females 

 have their proper periodical seasons. If, however, we proceed a 

 little eastward to Ava, we hear from Mr. Crawfurd u that their 

 " breeding in the domestic state, or at least in the half-domestic 

 state in which the female elephants are generally kept, is of every- 

 day occurrence ;" and Mr. Crawfurd informs me that he believes 

 that the difference must be attributed solely to the females being 

 allowed to roam the forest with some degree of freedom. The 

 captive rhinoceros, on the other hand, seems from Bishop Heber's 

 account 15 to breed in India far more readily than the elephant. 

 Four wild species of the horse genus have bred in Europe, though 

 here exposed to a great change in their natural habits of life ; but 

 the species have generally been crossed one with another. Most of 



11 Du Rut, 'Aunales du Museum,' 1863, vol. i. pp. 99, 193; vol. ii. p. 



1807, torn. ix. p. 120. 113. 



'- ' Saugethiere von Paraguay,' u ' Embassy to the Court of Ava, 



1830, s. 49, 106, 118, 124, 201, 208, vol. i. p. 534. 



49, 265, 327. I5 ' Journal,' vol. i. p. 213. 



13 • The Naturalist on the Amazons,' 



o 



