The Descent of Man

ginally have been equally bright coloured; but
that subsequently, the females from the danger
incurred during incubation, and the young
from being inexperienced, had been rendered
dull as a protection. But this view is not supported
by any evidence, and is not probable;
for we thus in imagination expose during past
times the females and the young to danger,
from which it has subsequently been necessary
to shield their modified descendants. We have,
also, to reduce, through a gradual process of
selection, the females and the young to almost
exactly the same tints and markings, and to
transmit them to the corresponding sex and
period of life. On the supposition that the females
and the young have partaken during each
stage of the process of modification of a tendency
to be as brightly coloured as the males, it
is also a somewhat strange fact that the females
have never been rendered dull-coloured without
the young participating in the same change;
for there are no instances, as far as I can