perfection without exercise or training, and while the animal exists as
passively as a fruit on its stem.

I have observed that the helpless young of some of the mammals I have
just mentioned seem at first to have no instinctive understanding of the
language of alarm and fear in the parent, as all young-birds have, even
before their eyes are open. Nor is it necessary that they should have
such an instinct, since, in most cases, they are well concealed in
kennels or other safe places; but when, through some accident, they are
exposed, the want of such an instinct makes the task of protecting them
doubly hard for the parent. I once surprised a weasel (Galictis barbara)
in the act of removing her young, or conducting them, rather; and when
she was forced to quit them, although still keeping close by, and
uttering the most piercing cries of anger and solicitude, the young
continued piteously crying out in their shrill voices and moving about
in circles, without making the slightest attempt to escape, or to
conceal themselves, as young birds do.

Some field mice breed on the surface of the ground in ill-constructed
nests, and their young are certainly the most helpless things in nature.
It is possible that where this dangerous habit exists, the parent has
some admirable complex instincts to safeguard her young, in addition to
the ordinary instincts of most animals of this kind. This idea was
suggested to me by the action of a female mouse which I witnessed by
chance. While walking in a field of stubble one day in autumn, near
Buenos Ayres, I suddenly heard, issuing from near my feet, a chorus of
shrill squealing voices--the familiar excessively sharp little needles
of sound emitted by young, blind and naked mice, when they are disturbed
or in pain. Looking down, I saw close to my foot a nest of them--there
were nine in all, wriggling about and squealing; for the parent,