Childrens Illustrated Encyclopedia

331

MaMMal groups

There are about 27 main groups of mammals,

some of which are shown below. Rodents make

up half of all mammals; bats account for one-

quarter. There are only three kinds of elephants,

and the aardvark is in a group of its own.

Camels, horses, and

other hoofed mammals

Seals, sea lions,

and walruses

Monkeys,

apes, and

other primates

Cats, dogs, and

other carnivores

HaiR and fuR

fur or hair protects the mammal’s skin from injury and the

sun’s rays. it also keeps heat in and moisture out. The colors

and patterns of the fur provide camouflage. Water-dwelling

mammals such as beavers have special oily, waterproof fur.

The porcupine’s spines are modified hairs and the rhinoceros’s

horn is made from a hair-like fibrous substance.

aRmadillo

Some mammals, such as

armadillos and pangolins,

have reptilelike scales instead

of fur. The scales, or scutes,

of an armadillo are made of

a type of horn and bone that

grows from the skin. Hairs

grow between the scutes and

also cover the animal’s soft-

skinned underbelly.

mammal milk

mammals are the only creatures that feed their young with milk.

When the female is about to give birth, she starts to produce

milk in mammary glands on the chest or abdomen. When the

young are born, they suck the milk from the mother’s teats.

mother’s milk is an ideal food for the young—warm and

nourishing, and full of special substances that protect the young

from disease. as the babies grow larger and stronger, they take less

milk and begin to eat solid foods. This process is called weaning.

gestation

The time between mating and

birth, when the young develop

in the mother’s womb, is called

the gestation or pregnancy

period. in general, large

mammals have longer

pregnancies and

fewer young than

small mammals.

Body TempeRaTuRe

mammals and birds are called warm-blooded

animals because they can maintain a high body

temperature even in cold conditions. mammals do,

however, need plenty of food to provide the energy

for warmth. The heat to warm a mammal is

produced by chemical reactions in the body,

particularly in the muscles.

Elephants

Bats and

flying foxes

Sea cows

and dugongs

Hares, rabbits,

and pikas

Anteaters,

armadillos,

and other

toothless

mammals

Aardvarks

Humans

Hedgehogs, moles,

and other insectivores

Squirrels,

rats, mice,

and other

rodents

Tree

shrews

Whales,

dolphins,

and porpoises

Dirty fur harbors pests and

also lets heat escape, so

many mammals spend

time cleaning or

grooming their fur.

Gestation usually lasts for 30 days; as many

as eight young are born in a litter.

Rhinoceros

Most puppies feed on their

mother’s milk for two or three

months. A mother shrew

suckles her young for four

weeks; a mother whale feeds her

youngster for six months or more.

The gestation usually lasts for 15 months;

one young is born.

Huskies are able to stay

warm in deep snow

because of their thick fur.

Rabbit

Find out more

animals

animal senses

elephants

farm animals

flight, animal

Hibernation

prehistoric life

MaMMals

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