The yak of central Asia is very bison-like
in some respects, but in others departs in the direction of oxen.
So at last, group by group, we have gone through the ungulates, and the
bisons alone are left, and as the American animal has short, incurved
horns, set low down on the skull and far apart at the base;
premaxillaries falling short of the nasals; the last cervical and the
anterior dorsal vertebrae with spines; fourteen pairs of ribs, and a
mane covering the shoulders, we conclude that it is a bison, and as the
same characteristics with minor variations are shown by the European
species, often, but wrongly, called "aurochs," we say that these two
alone of existing _Bovidae_ are bisons, with the yak as a somewhat
questionable relative.
In all essential respects the two bisons are very similar, but minute
comparison shows that the European species, _Bison bonasus_, has a
wider and flatter forehead, bearing longer and more slender horns, and
all the other distinctive features are less pronounced. In the American
species, _Bison bison_, the pelvis is less elevated, producing the
characteristic slope of the hindquarters.
Pages:
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75