(I) Bats live in caves to avoid danger and save energy.
(II) Some species spend their daytime in caves while
others hibernate there for the winter because caves
provide optimal humidity, a stable low temperature, and
few disturbances from light or noise. (III) Temperature is
important because bats are warm-blooded but very
small. (IV) Hibernation is a deep state of inactivity in
which the animals' body temperature decreases.
(V) Unlike many other mammals, bats let their internal
temperature drop when they are resting, going into a
state of decreased activity to conserve energy