The Making of Species 
Bird fanciers when crossing the canary with 
wild species of finch, almost invariably use a hen 
canary as the female parent, because domesticated 
female animals breed more readily than do captive 
wild ones. 
The domestic yak breeds frequently in the 
Himalayas with the perfectly distinct zebu or 
humped cow of India, and the hybrids are fertile. 
Yet the zebu and the Indian buffalo, living con- 
stantly side by side in the plains of India, never 
interbreed at all. 
Among wild ruminants of this hollow-horned 
family, the Himalayan Argali (Ovzs ammon) ram, 
a giant sheep of the size of a donkey, has been 
known to appropriate a herd of ewes of the Urial 
(O. vignez), a very distinct species of the size of 
a domestic sheep. Many hybrids were born, and 
these, in turn, bred with the pure urials of the 
herd. 
In our parks the little Sika deer of Japan 
(Cervus stka), a species about the size of the 
fallow-deer, with an even more marked seasonal 
change of colouration and antlers having only 
three tines, breeds with the red deer, and the 
hybrids are fertile. 
In certain parts of Asia Minor the natives 
cross the female one-humped camel with the male 
of the bactrian or two-humped species. The 
hybrids (which are one-humped) will breed with 
the pure species; but, although the hybrids are 
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