We here see that there is no need to separate single pairs, as man does,
when he methodically improves a breed: natural selection will preserve and
thus separate all the superior individuals, allowing them freely to
intercross, and will destroy all the inferior individuals. By this process
long-continued, which exactly corresponds with what I have called
unconscious selection by man, combined, no doubt, in a most important
manner with the inherited effects of the increased use of parts, it seems
to me almost certain that an ordinary hoofed quadruped might be converted
into a giraffe.
To this conclusion Mr. Mivart brings forward two objections. One is that
the increased size of the body would obviously require an increased supply
of food, and he considers it as "very problematical whether the
disadvantages thence arising would not, in times of scarcity, more than
counterbalance the advantages." But as the giraffe does actually exist in
large numbers in Africa, and as some of the largest antelopes in the world,
taller than an ox, abound there, why should we doubt that, as far as size
is concerned, intermediate gradations could formerly have existed there,
subjected as now to severe dearths. Assuredly the being able to reach, at
each stage of increased size, to a supply of food, left untouched by the
other hoofed quadrupeds of the country, would have been of some advantage
to the nascent giraffe.
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