Valletta
Form of
government
Republic
Major
localities
Birkirkara,
Qormi, Mosta,
Zabbar, Valletta
34 Malta BRITANNICA STUDENT ENCYCLOPEDIA
Malvinas
#see Falkland Islands.
Mammal
A mammal is an animal that breathes
air, has a backbone, and grows hair at
some point during its life. In addition,
all female mammals have glands that can
produce milk to feed their young. Mammals
are among the most intelligent of
all living creatures. They have an ability
to learn that no other type of animal can
match.
Mammals include a wide variety of animals,
from cats to humans to whales.
There are about 5,000 species, or kinds,
of living mammal. More than half of all
mammals are rodents, a group that
includes mice and squirrels.
Where Mammals Live
Mammals are found in every major
habitat around the world. Most mammals
live on land—on the ground, in
trees, or even underground. Some
mammals—including otters, beavers,
and seals—live on land and in the water.
Whales, dolphins, and manatees are
mammals that spend their whole life in
water.
Physical Features
Mammals range in size from a tiny bat
to a huge whale. The Philippine
bamboo bat weighs only about 0.05
ounce (1.5 grams). The blue whale is
the largest animal on Earth. It may be
more than 100 feet (30 meters) long
and may weigh 200 tons (180,000
kilograms).
Bats and whales are unusual mammals,
however. Most mammals have four legs
for moving around on land. But bats
have two wings for flying and two hind
legs for grasping. Whales have two flippers
and a tail for swimming.
Although dolphins look like fish and live in
the water, they are actually mammals.
A polar bear mother feeds milk to her two
cubs. Mammals are the only animals that
nurse their young.
BRITANNICA STUDENT ENCYCLOPEDIA Mammal 35
Mammals are the only animals that
nurse their young with milk that they
produce. The female has special glands
called mammary glands. After childbirth,
the mother’s glands produce milk.
The mother feeds the young with this
milk until the young are old enough to
get food for themselves.
All mammals have hair at some stage of
development. Many whales have hair
only before they are born. But other
mammals have thick coats. Hair helps to
keep the body warm. The color and
pattern of the hair also may help a mammal
to blend in with its surroundings.
This may keep a mammal hidden from
its enemies. In some mammals, hair
takes a special form. The hair of porcupines
is hardened into sharp spines. A
cat’s whiskers are special hairs that are
highly sensitive to touch.
Mammals are warm-blooded. This
means that they are able to keep their
body at roughly the same temperature
no matter what the surrounding temperature
is. This allows mammals to live
in a wide range of climates.
Finally, mammals have a highly developed
brain. The mammal brain is the
most complex organ known. This complex
brain allows mammals to learn
from experience and adapt, or change,
their behavior.
Behavior
Young mammals learn many
behaviors—for example, how to hunt—
from their parents. Some young mammals
go off on their own once they have
grown up. Others stay within their family
groups for life.
Individual mammals or groups may live
in areas called territories. These mammals
may fight off other mammals of
the same species that try to enter their
territory. Some groups of mammals
migrate, or move between places during
different seasons.
Some mammals, including ground
squirrels and hedgehogs, hibernate during
winter. Hibernation is a very deep
form of sleep during which an animal’s
body temperature drops.
Mammals eat a wide variety of foods.
Mammals that eat other animals are
called carnivores. Cats, dogs, weasels,
walrus, and many other mammals are
carnivores. Mammals that eat plants—
such as lemmings, deer, cattle, and
Highland cattle have long coats of hair. All
mammals grow hair at some point in their
development.
36 Mammal BRITANNICA STUDENT ENCYCLOPEDIA
elephants—are called herbivores. Mammals
that eat both animals and plants
are called omnivores. Omnivores include
raccoons, bears, and primates.
Reproduction
Mammals reproduce through mating. In
nearly all mammals, the female carries
the developing young in her body after
mating. The young develop inside a part
of the mother’s body called the uterus,
or womb. They receive nutrition
through the mother’s body.
Gestation, or the length of time that the
mother carries the young in the womb,
varies between species. Pregnancies in
hamsters last about two weeks.
Elephants may be pregnant for up to 22
months. Human pregnancies last about
nine months.
Nearly all female mammals give birth to
live young. At birth, the young of some
mammals are well developed and able to
move about at once. For example, newborn
horses and camels can walk within
hours after birth. In other mammals—
including rabbits and most rodents—the
young are born mostly developed but
blind, hairless, and helpless.
Marsupials are a group of mammals that
give birth to underdeveloped young.
Marsupials have short pregnancies of
about six weeks. After birth, the young
marsupial crawls into a pouch or fold on
the mother’s belly. The young stays there
