CLASS I. MAMMALIA: ORDER 9. RUMINANTIA. 
483 
THE YAK. 
species breeds with common cattle, and the mixed races are greatly vakied. 'They seem to be 
adapted to cold countries, and thrive best in the lofty plateaus between the Altai, Himalaya, 
and Belur Tag mountains. In summer the wild kinds shrink from the heat, and hide them- 
selves in the shade and water. The young are produced in winter; these are at first covered with 
rough, curly black hair; at three months they obtain the long hair on the body and tail. 
Several living specimens of the Yak have been taken to Europe, and in France the experi- 
ment is being made of bringing them into use, it being deemed a valuable breed on account of 
its long hair, and other qualities. Several young ones have been produced there. 
Subgenus BONASUS or BISON" : Bison according to Smith. — Of this there are two species, 
one European, and now nearly extinct; the other American, and still existing in large numbers. 
These animals are chiefly distinguished from the ox by having the forehead much larger and 
more rounded between the horns; the feet smaller, with a thicker and more woolly covering; and, 
finally, by possessing one more rib — that is, fourteen instead of thirteen. 
The European species of Bison is the Aurochs, the Bos Bonasus of Linnaeus. This animal, 
which was formerly, though erroneously, supposed to be the origin of our domestic cattle, was 
once spread throughout the forests of Europe, but has gradually disappeared before the approach 
of man, and is now only known in the remote parts of Lithuania, Moldavia, Wallachia, and parts 
of the Caucasus. As foimd at the present day, it has a very broad head and arched forehead; 
the eyes are large and dark ; the hair on the forehead is long and wavy, and under the chin and 
breast forms a kind of beard. In the winter, the whole of the neck, hump, and shoulders are 
covered with a long dusky-brown hair, intermingled with a soft fur. The long hair is cast in 
the summer and renewed in the winter. The tail is of moderate length, covered with hair, and 
is terminated in a large tuft. The females are not so large as the males, and have not so much 
hair on their bodies. 
These animals have never been domesticated, but herds of them are protected in certain locali- 
ties in the forest of Bialowieza in Lithuania, imder the direction of the Emperor of Russia. There 
are twelve herds thus kept, each being under the superintendence of one herdsman. The esti- 
mated number of all the herds is eight hundred, these not including the wild troops of the Caucasus. 
They feed on grass and brushwood, and the bark of young trees, especially the willow, poplar, ash, 
and birch. They do not attain their full stature till their sixth year. They are very shy, and can 
only be approached from the leeward, as their smell is exceedingly acute. When accidentally 
fallen in with they become furious, and passionately assail the intruder. When taken young they 
become accustomed to their keeper, but the approach of other persons excites their anger. Two 
