An African student uses a
pointer and blackboard.
BRITANNICA STUDENT ENCYCLOPEDIA Eel 107
Behavior
Many species of eel hide in mud or
among rocks during the day. They come
out at night to hunt for food. Eels eat
shrimps, snails, fishes, mussels, and
worms.
Eels generally live alone. But garden eels
live in colonies of hundreds of eels. Each
garden eel hides in a tube that it digs in
the sandy ocean floor.
Eels breathe through gills, as other fishes
do. But freshwater eels also can absorb
oxygen through their skin. This allows
them to move across land.
Life Cycle
Baby eels, or larvae, hatch from eggs in
the ocean. The larvae are typically flat
and transparent. After a period of
growth, they go through metamorphosis.
This is a series of changes that turn
the larvae into young eels, or elvers. Elvers
look like miniature adult eels.
After the elvers reach adulthood, they
are ready to mate. Most species migrate,
or travel, to a particular area to mate and
lay eggs.
#More to explore
Fish • Metamorphosis
Egg
The young of most animals grow from
eggs. Only female animals make eggs.
Male animals make cells called sperm. A
sperm must join an egg before the egg
can grow into a new animal.
In most mammals, the egg is just a cell,
called an ovum, inside the mother’s
body. A sperm cell joins with the egg cell
in a process called fertilization. The fertilized
egg grows and develops inside the
mother until the baby is ready to be
born. Most other female animals lay
eggs, or release them outside their body
to develop.
Eggs need protection while the young
develop inside them. Fish eggs often
float in a protective jelly. Bird and reptile
eggs have an outer shell. In bird eggs the
shell is hard; in reptile eggs it is tough
and elastic. Eggs with shells contain an
egg cell and food, called yolk, for the
developing young, called an embryo.
Many animals, including humans, eat
the eggs of other animals. Fish eggs,
called roe or caviar, are common in
Japanese food. People around the world
eat bird eggs, especially those of chickens
and ducks.
Scientists consider
the fish
called electric
eels to be different
from
true eels. Electric
eels live in
South American
waters.
Some insects, such as ladybugs, lay their
eggs on plant leaves or stems.
108 Egg BRITANNICA STUDENT ENCYCLOPEDIA
Egypt
The Arab Republic of Egypt is a country
in the northeastern corner of Africa.
Ancient Egypt was one of the earliest
and most important civilizations in the
world. The modern country plays a key
role in Middle Eastern politics. Egypt’s
capital is Cairo.
Geography
Egypt shares borders with Libya, Sudan,
Israel, and the Palestinian territory of
the Gaza Strip. Egypt’s northern coast is
on the Mediterranean Sea, and its eastern
coast is on the Red Sea. The Nile
River flows northward into the Mediterranean.
It fans out into the Nile delta, a
triangular area at the mouth of the river.
The Nile divides Egypt into theWestern
Desert and the Eastern Desert. The
Western Desert is low-lying and generally
flat. The Eastern Desert has rolling
hills and mountains in the southeast. To
the northeast is the Sinai Peninsula, the
only land bridge between Africa and
Asia. The Suez Canal separates Sinai
from the rest of Egypt.
Egypt has only two real seasons: a cool,
mild winter and a hot summer. The
climate is very dry and sunny.
Plants and Animals
TheWestern Desert has very few plants.
The Eastern Desert and Sinai have
thorny shrubs, small desert plants, and
herbs. The acacia is one of the few native
trees. Around the Nile are date palms
and many water plants, including reeds
and grasses.
Egypt’s wild animals include mountain
sheep and goats, gazelles, miniature
desert foxes, hares, jackals, and mongooses.
Rodents, insects, lizards, and
snakes are also common. Many types of
birds live in Egypt year-round or pass
through on their migrations.
People
Most Egyptians are descendants of the
Hamites of ancient Egypt and of the
Arabs who migrated to Egypt centuries
ago. Other groups include Nubians,
Roma (Gypsies), Armenians, and
Greeks. Arabic is the official language,
and Islam is the official religion. About
15 percent of Egyptians are Christians,
mostly members of the Coptic Orthodox
Church. Egypt also has a small Jewish
community. Almost all Egyptians
BRITANNICA STUDENT ENCYCLOPEDIA Egypt 109
live in the Nile valley and delta. More
than half of the people live in rural
areas.
Economy
Mining and manufacturing are important
parts of Egypt’s economy. The
country mines petroleum (oil) and natural
gas. It produces valuable crude oil,
cotton goods, processed foods, chemicals,
iron, and steel.
About one fourth of workers are farmers.
Much of Egypt’s farming income
comes from cotton and rice, which it
sells to other countries. Other crops
include sugarcane, corn, tomatoes,
wheat, potatoes, oranges, dates, and
grapes.
Tourism is also very important to the
economy. Visitors come to see the Great
Pyramids at Giza, the Sphinx, and other
monuments of ancient Egypt.
History
Native kings and queens ruled in ancient
Egypt for most of the country’s first
2,500 years, from about 2925 BC until
332 BC. In 332 BC Alexander the Great,
