body of an ant is divided into three sections:
the head, the thorax (midsection),
and the abdomen. The head is large, and
the abdomen is slender and oval. The
thorax is connected to the abdomen by a
small waist. Two antennas are located on
the top of the head. Ants use their
antennas for guidance, smell, and communication.
Most types of ant live in nests that they
make from many different materials,
including soil, sand, wood, and leaves.
Some ants build anthills.Within each
nest there is usually a queen, workers,
and soldiers. The queen spends her life
laying eggs. The workers are females
who do the work of the nestfor
example, collecting food, cleaning the
nest, and caring for eggs. Soldiers are
larger females who defend the colony.
They also raid other colonies and often
capture slaves.
At certain times of the year, many species
produce winged males and queens.
The males only purpose is to mate with
the queens. The males and the queens
fly into the air to mate. The males die
soon afterward. Each queen then lays
her eggs and sets up a new nest. It takes
several weeks for the eggs to develop
into adults. Most ants live for 6 to 10
weeks, though some live up to 15 years.
#More to explore
Insect
Harvester ants work to store grass, seeds,
and berries in their nest.
Carpenter ants like wood of all kinds. They
make their nests in live or dead trees or in
wooden structures such as telephone poles
and porches.
BRITANNICA STUDENT ENCYCLOPEDIA Ant 133
Antananarivo
Population
(2001 estimate)
1,403,449
Antananarivo is the capital of Madagascar,
an island country off the southeastern
coast of Africa. Antananarivo stands
on a high hill in the countrys central
highlands. It is the largest city in Madagascar
by far.
Antananarivos historic sites include
royal palaces from the 1800s. The city
also has Anglican and Roman Catholic
cathedrals and the National Library. The
University of Madagascar was opened in
the city in 1961.
Antananarivo has been a government
center for hundreds of years. Many of
the citys residents work for the government
of Madagascar. Banking and business
services are also important to the
economy. The citys factories process
tobacco and make foods, leather, and
clothing.
Antananarivo began as a fortress town
in the 1600s. It became the capital of
the Merina kingdom in the 1700s. In
1895 French troops took control of the
town. Within 10 years the French
controlled most of the island. They
made the town the capital of their
colony. In 1960 the colony became an
independent country with its capital at
Antananarivo. The city grew quickly in
the late 20th century.
#More to explore
Madagascar
The sun sets on the hilly city of Antananarivo.
134 Antananarivo BRITANNICA STUDENT ENCYCLOPEDIA
Antarctica
The southernmost continent in the
world, Antarctica surrounds the South
Pole. Its name means opposite to the
Arctic (the Arctic is the region around
the North Pole). Antarctica is larger than
both Europe and Australia. But it has no
permanent human population.
Land
An ice sheet covers nearly all of Antarctica.
It contains 90 percent of the
worlds ice and 70 percent of the worlds
freshwater. At its thickest point the ice
sheet is 15,670 feet (4,776 meters) deep.
Around the coast, glaciers continually
break off icebergs into the sea.
The continent has two unequal parts.
The larger is generally known as East
Antarctica, while the smaller is West
Antarctica.West Antarctica includes the
Antarctic Peninsula, an 800-mile
(1,300-kilometer) extension of the continent
that juts northward toward the
southern tip of South America. The
Transantarctic Mountains separate East
andWest Antarctica. Mountains with
only their peaks showing through the
ice, known as nunataks, are found in
some areas. Antarctica has several active
volcanoes.
About 2 percent of Antarctica is ice-free.
These unusual land areas, called oases,
are mostly found near the coast. They
include the dry valleys of southern Victoria
Land and the Bunger Oasis in
Wilkes Land.
Penguins are among the few animals that can survive the very cold temperatures of
Antarctica.
BRITANNICA STUDENT ENCYCLOPEDIA Antarctica 135
136 Antarctica BRITANNICA STUDENT ENCYCLOPEDIA
Antarctica does not have 24-hour periods
divided into days and nights. At the
South Pole the sun rises on about September
21 and moves in a circular path
until it sets on about March 22. This
day, or summer, is six months long.
From March 22 until September 21 the
South Pole is dark, and Antarctica has its
night, or winter.
Antarctica is the coldest continent. The
average annual temperature in the
interior is .70° F (.57° C). But the
coast is warmer. Along the Antarctic
Peninsula temperatures can rise up to
59° F (15° C).
Plants and Animals
The extreme cold has kept the
continent almost empty of life. Some
mosses and liverworts grow in ice-free
areas along the coast, and two types of
flowering plants grow on the peninsula.
Native land animals are limited to
certain kinds of arthropods, or
insectlike animals.
About 45 kinds of birds live in Antarctica.
The emperor and the Adelie penguins
are found in large numbers around
the entire coastline. Gentoo and chinstrap
penguins occupy the Antarctic
Peninsula coasts and some islands. Several
kinds of seals and whales inhabit the
waters around Antarctica. Fishes limited
to the Antarctic include the Antarctic
cod and the icefish.
History
The first recorded landing on Antarctica
was on Cape Adare in 1895. The first
people to spend a winter on the continent
did so in a ship that was caught in
ice at Cape Adare during the period
from March 1898 to March 1899.
Englishmen Robert F. Scott and Ernest
Henry Shackleton led three expeditions
to the Antarctic between 1901 and
1913. They pioneered routes into the
interior of the continent, and the
research they conducted provided a base
for present-day scientific programs. On
December 14, 1911, Roald Amundsen
of Norway became the first person to
reach the South Pole. Many other expeditions
followed.
Every year hundreds of researchers travel
to Antarctica to conduct experiments.
Widespread scientific investigation of
Antarctica began during the International
Geophysical Year in 195758. In
1959, 12 countries signed the Antarctic
Treaty to reserve the continent for
peaceful, scientific purposes. By 2000,
44 countries had signed the treaty.
#More to explore
Amundsen, Roald Continent Glacier
Iceberg Penguin Polar Exploration
Facts About
ANTARCTICA
Area
5,400,000 sq mi (14,200,000 sq km)
Population
No permanent population
Coldest Recorded Temperature
July 21, 1983, Vostock Station: .129° F
(.89° C)
Hottest Recorded Temperature
January 5, 1974, Lake Vanda: 59° F (15° C)
BRITANNICA STUDENT ENCYCLOPEDIA Antarctica 137
Anteater
Anteaters are curious-looking animals.
Their long heads and snouts look like
tubes, and they have no teeth at all. Anteaters
use their strong front legs and
heavy claws to break open nests of ants