HYBRIDIZATION IN ANIMAL BREEDING 521 



gayal, Bibos frontalis; with the gaur, Bibos gaurus; with the zebu, Bos 

 indicus, and with the American bison, Bison americanus. Apparently 

 all these hybrids are fertile in the female sex, and sterile in the male. 

 They are commonly more vigorous than the parents, and in some cases 

 they provide a source for breed improvement for specific purposes. 

 These features are discussed hi the next following chapter, in which 

 illustrations also will be found. 



Many other species hybrids have been reported among domestic 

 animals. Thus there are persistent reports of hybrids between the sheep 

 and goat. In fowls a great variety of strange hybrids have been pro- 

 duced. Brentana lists thirteen remarkable hybrids in the Phasianidae 

 among them peacock-guinea fowl, pheasant-fowl, guinea fowl-fowl, 

 and various pheasant species crosses. Although of technical interest these 

 hybrids do not promise to yield anything of commercial value. 



