The Descent of Man

can be maintained with confidence, only when
the young of several species resemble each other
closely, and likewise resemble other adult
species belonging to the same group; for the
latter are the living proofs that such a state of
things was formerly possible. Young lions and
pumas are marked with feeble stripes or rows
of spots, and as many allied species both young
and old are similarly marked, no believer in
evolution will doubt that the progenitor of the
lion and puma was a striped animal, and that
the young have retained vestiges of the stripes,
like the kittens of black cats, which are not in
the least striped when grown up. Many species
of deer, which when mature are not spotted,
are whilst young covered with white spots, as
are likewise some few species in the adult state.
So again the young in the whole family of pigs
(Suidae), and in certain rather distantly allied
animals, such as the tapir, are marked with
dark longitudinal stripes; but here we have a
character apparently derived from an extinct