334 TROPICAL AGRICULTURE 



and pleasure uses, and in Brazil there is a quite unusual inter- 

 est in horse breeding. 



The African ass, the source of the domestic ass, still roams 

 wild in various parts of Africa and quite generally in tropical 

 countries it escapes and "goes wild" again. Mules are gen- 

 erally used in tropical America for work purposes but to a 

 less extent in the African and Oriental Tropics. In the ex- 

 perience which has been had in the Tropics with mules, no 

 reason has been developed for considering the mule more im- 

 mune to diseases than is the horse. 



Zebras have been tamed and bred in captivity and main- 

 tained as work animals in a number of tropical countries. 

 Zebras are not susceptible to tsetse-fly disease and therefore 

 give some promise of becoming work animals where the horse 

 and mule are exterminated by tropical diseases. Zebroids, or 

 the crosses between zebra stallions and mares, have been pro- 

 duced in a number of localities and have given good accounts 

 of themselves. In making these crosses draft breeds of mares 

 are used to produce work zebroids, and thoroughbred mares 

 in the production of driving and riding zebroids. Thus far 

 the most important breeding work in the production of ze- 

 broids has been done by Ewart in England and Baron de 

 Parana in Brazil. The consensus of opinion of those who 

 have had practical experience with zebroids is that these ani- 

 mals are very tractable, graceful, and of great endurance. 



SWINE 



Like the other familiar domestic animals of Europe and 

 northern America, the hog in the Tropics shows an extremely 

 irregular distribution, due to local conditions and customs. 

 Throughout the Pacific and South Sea Islands, including Ha- 

 waii, and particularly in southern China and Brazil, the hog 

 industry is an important one and pork constitutes a large 

 feature of the diet. Elsewhere in the Tropics, the pig is a less 



