A great number of both large and small mammals live solitary lives
except for brief periods during the mating season or the association
of the young with the mother. Some species, however, like the wolves
and coyotes, may mate permanently and show great mutual affection and
constancy. Many species have well-developed social instincts, which
appear in some cases to combine two purposes, self-defense and the
desire for companionship.
Herds of large herbivorous mammals, such as musk-oxen and buffalo,
frequently present a solid array of bristling horns to the attacking
wolves, and thus protect the weaker members of the herd and give an
example of the usefulness to them of the social instinct. Wolves and
some other predatory animals hunt in couples or in packs and succeed in
pulling down prey which singly they could not successfully attack.
Prairie-dogs living in colonies have the advantage of community
intercourse as well as added safety through the chance that some member
of the colony will espy an approaching enemy and by its warning cry
allow a safe retreat. In other cases, such as the flying-squirrels,
which gather in considerable numbers in hollow trees or other shelter,
and the bats, which gather in caves, the congregation appears to be
purely from a desire for close companionship.
[Illustration: FOOTPRINTS OF NATURE’S WILD FOLK