On the whole we may conclude, more especially from the researches of Boyd
Dawkins, that European cattle are descended from two species; and there is
no improbability in this fact, for the genus Bos readily yields to
domestication. Besides these two species and the zebu, the yak, the gayal,
and the arni (3/47. Isid. Geoffroy Saint-Hilaire 'Hist. Nat. Gen.' tome 3,
96.) (not to mention the buffalo or genus Bubalus) have been domesticated;
making altogether six species of Bos. The zebu and the two European species
are now extinct in a wild state. Although certain races of cattle were
domesticated at a very ancient period in Europe, it does not follow that
they were first domesticated here. Those who place much reliance on
philology argue that they were imported from the East. (3/48. Idem tome 3
pages 82, 91.) It is probable that they originally inhabited a temperate or
cold climate, but not a land long covered with snow; for our cattle, as we
have seen in the chapter on Horses, have not the instinct of scraping away
the snow to get at the herbage beneath. No one could behold the magnificent
wild bulls on the bleak Falkland Islands in the southern hemisphere, and
doubt about the climate being admirably suited to them. Azara has remarked
that in the temperate regions of La Plata the cows conceive when two years
old, whilst in the much hotter country of Paraguay they do not conceive
till three years old; "from which fact," as he adds, "one may conclude that
cattle do not succeed so well in warm countries." (3/49. 'Quadrupedes du
Paraguay' tome 2 page 360.)

Bos primigenius and longifrons have been ranked by nearly all
palaeontologists as distinct species; and it would not be reasonable to
take a different view simply because their domesticated descendants now
intercross with the utmost freedom. All the European breeds have so often
been crossed both intentionally and unintentionally, that, if any sterility
had ensued from such unions, it would certainly have been detected. As
zebus inhabit a distant and much hotter region, and as they differ in so