What Is a Mammal?
All mammals, from bats to whales,
share a number of important traits that make them different from other
creatures. For one thing, mammals spend much more time raising and
training their young than other animals do.
Mother’s Milk
Almost all mammals give birth to live young, rather than laying
eggs, as birds do. Female mammals are the only creatures on
earth that make milk for their young. The milk is rich in
vitamins, minerals, and all the other nutrients a young animal
needs.
The
Heat Is Always On
Unlike the cold-blooded
reptiles, which often need to lie in the morning sun to warm up,
the warm-blooded mammals are always ready to go. Their bodies
make enough heat to stay at the same temperature and work right
at all times.
Bigger, Better Brains
Mammals have larger, more
well-developed brains than other animals. Most mammals have
memories and are able to learn new things. This means that
mammals can learn to survive in new situations and in new places
if they need to. This is called adapting.
A Whale of a Brain
Scientists believe that
large marine mammals like whales and dolphins have brains much
like those of humans. They are able to communicate, follow
instructions, and figure things out.
Fur Coats
Mammals are the only animals with
hair. A mammal’s hair, which we often call its fur, protects it from
wind, rain, sun, cold, insects, and other things. Most mammals have a
fur coat with two distinct layers: an undercoat of shorter dense hair
and an outer coat of longer stiffer hairs.
Polar
Fleece
The Polar Bear has fur on
the pads of its feet, both to keep its feet warm and to help it
get a good grip on icy surfaces. The hairs of its thick
waterproof coat are hollow, which means that air gets trapped
inside each hair. The trapped air holds in body heat and also
helps the bear float when it swims.
