lives underground.Without light, they
are usually white or transparent (clear)
and do not have eyes. Blind animals
found in caves include many different
insects and spiders, types of shrimp, and
some salamanders.
Animals that live in caves have special
characteristics to help them survive.
Those characteristics are called adaptations.
Cave animals may not have sight,
but their other senses are highly developed.
For example, insects that live in
caves usually have very long antennae to
feel their way around. Other animals
can feel vibrations, which tell them that
something to eat is nearby.
Uses of Caves
People have been using caves for a long
time. Early humans often camped in the
entrances of caves. All over the world
there are caves that people used as a
place to live. In Europe there are caves
with drawing of animals that are more
than 15,000 years old. Scientists study
these caves and drawings to learn more
about how the people lived.
Caves are also used for recreation. There
are many caves that people can visit
without special equipment. Visitors to
other caves need special equipment and
lights. These caves require training to
explore.
#More to explore
Adaptation • Bat • Limestone
Cayuga
The Cayuga were one of the five original
Native American tribes of the Iroquois
Confederacy. The confederacy was an
alliance of tribes that lived in upper New
York State and spoke similar languages.
The Cayuga originally lived around
Cayuga Lake.
Like the other Iroquois, the Cayuga
lived in longhouses. They made longhouses
by covering a wooden frame with
wood and bark. Longhouses were large
The Big Room
in Carlsbad
Cavern in the
U.S. state of
New Mexico is
about 2,000
feet (610
meters) long
and 255 feet
(78 meters)
high.
Red Cloud was a chief of the Cayuga tribe.
64 Cayuga BRITANNICA STUDENT ENCYCLOPEDIA
enough to house several families.
Cayuga men hunted animals and birds
and also fished.Women grew corn,
squash, and beans.
Throughout the late 1600s the Iroquois
fought and won many wars with other
Indian tribes. The Cayuga took into
their tribe many people from the tribes
they defeated, including the Erie and the
Huron. Like most of the other Iroquois,
the Cayuga sided with the British in the
American Revolution (1775–83). After
the Americans won, settlers gradually
took over the Cayuga homeland. Many
Cayuga moved to Canada, Oklahoma,
or western New York. At the end of the
20th century there were about 2,000
Cayuga. Half of them lived in the
United States, and half lived in Canada.
#More to explore
Iroquois • Native Americans
Cedar
Cedars are evergreen trees that belong to
the pine family. Their wood is highly
valued because it does not rot easily. It
also has a beautiful reddish color and a
pleasant smell.
There are four species, or types, of cedar.
Three of them originally grew only in
the mountains around the Mediterranean
Sea. They later spread to other
areas. The other species grows in the
Himalaya Mountains of southern Asia.
Cedars are tall trees with spreading
branches. They can grow to a height of
more than 100 feet (30 meters). Cedars
have leaves that are like needles. They
grow in clusters along the branches.
Cedars also produce large cones that
hold their seeds.
Many other trees that have fragrant,
reddish wood are called cedars. But most
of them are actually cypress or juniper
trees. Their wood is used to make clothing
chests, closets, and pencils. Oil taken
from the eastern red cedar, a juniper, is
used in perfumes.
#More to explore
Cypress • Juniper • Pine • Tree
Cell
Every organism, or living thing, is made
up of structures called cells. The cell is
the smallest unit with the basic properties
of life. Some tiny organisms, such as
bacteria and yeast, consist of only one
cell. Large plants and animals have many
billions of cells. Human beings are made
up of more than 75 trillion cells. The
study of cells is a branch of biology.
A group of cedars grows tall in Lebanon.
BRITANNICA STUDENT ENCYCLOPEDIA Cell 65
The Celts were one of the first peoples
in Europe to work with iron. They made
swords, shields, helmets, and gold and
silver jewelry.
The Celts practiced a religion called
Druidism. Their priests were called Druids.
The Druids taught that souls lived
forever by passing from one person to
another at the time of death.
Celtic power in western Europe lasted
for only a few hundred years. Then
Romans, Carthaginians (a people from
North Africa), and German tribes took
over. The Celts kept their unique culture
only in parts of the British Isles and in
the Brittany region of northwestern
France. Some people in Ireland, the
highlands of Scotland, the Isle of Man,
Wales, and Brittany still speak Celtic
languages.
#More to explore
Europe • Iron
Cement
The fine powder called cement is one of
the main ingredients of concrete. When
cement combines with water it becomes
a paste. This paste is used to hold
together all of the other materials that
make up concrete.
In ancient times people used clay or a
paste made of ground-up stone and
other ingredients to hold their buildings
together. Over the years people tried
other combinations of materials. In the
