MAMMALIA 401 



The United States Department of Agriculture has experimented 

 with the zebra and the quagga, hybridized with the horse, but has 

 been unable to secure any notable improvement over the mule. 

 The African quagga is now extinct. 



Artiodactyla. — Artiodactyla are even-toed ungulates in which the 

 third and fourth digits form a symmetrical pair. Premolars are 

 smaller than molars; stomach usually complex, cecum small. 

 Placenta diffuse or cotyledonary. 



The Artiodactyla are divided into the Ruminants and the Non- 

 Ruminants. The Ruminants are that extremely important group 

 of domestic animals which have been of service to man for thousands 

 of years — cattle, sheep, goats, and camels; also such non-domesti- 

 cated types as antelopes, deer and giraffes. The Non-Ruminants 

 include pigs, peccaries and the hippopotamus. 



The African hippopotamus or " river horse " once ranged over 

 Europe and India. It is thick skinned and almost devoid of hair. 

 Its perspiration is reddish. The hogs {Suidae) are important sources 

 of food supply. The United States produces over one-third of the 

 hogs of the world, and exports many. The wild boar has been hunted 

 for centuries by the sportsmen of Europe. Its tusks are elongated 

 canine teeth. The African wart hog has such a horrible appearance 

 that it is said to be the ugliest of mammals. Another African form, 

 the " red river hog" is one of the most beautiful of the Suidae, having 

 long slender ears and a glossy coat. The collared peccary ox javelin 

 (hunted on horseback in Mexico) and the white-lipped peccary range 

 from Mexico into South America, frequenting the upland jungles. 



The ruminants are animals that have four parts to their stomachs 

 and regurgitate the food from the rumen or paunch, chewing it as 

 the " cud." (See Figure 241, page 434.) 



The Chevrotains of India and Africa are hornless forms, resem- 

 bling both the deer and the pig. They have in some cases four toes 

 reaching the ground, do not chew the cud, and have simple stomachs 

 with only three chambers. The " deerlets " have changed but little 

 since the Miocene period. 



The Camelidae are able to retain twenty quarts of water in the 

 tightly closed water cells of the rumen of their stomachs, and march 

 for a week over the sanded wastes. Their nostrils are guarded by 

 valves, their tough cartilaginous mouth permits them to eat thorny 

 vegetation, and they walk over the sand on padded feet. The hujnp 

 of the camel is a reservoir of nutriment to the animal and a satis- 



