venom of most spiders is not harmful to
people. But a few spiders, including the
black widow and the brown recluse, can
cause pain and sometimes death in
humans.
Behavior
Spiders feed mostly on insects. Some
spiders are hunters that chase and overpower
their prey. These spiders typically
have a good sense of touch or sight.
Other spiders instead weave silk webs to
trap flying insects. Some spiders also use
silk to wrap their prey, protect their
eggs, or make nests.
Spiders are the only animals that digest
their food outside their bodies. After
capturing its prey, a spider covers it with
digestive juices. The juices break down
the prey’s body into a liquid form that
the spider sucks up. Spiders repeat this
process many times and eventually
digest most of the prey.
Life Cycle
Female spiders lay egg sacs that hold
several to a thousand eggs. The young of
most species go off on their own when
they come out of the egg sac. Spiders
change little in appearance as they grow.
They molt, or shed their outer covering,
multiple times before becoming adults.
#More to explore
Insect • Scorpion • Silk • Tick and Mite
Spinach
Spinach is a green leaf vegetable. It is a
rich source of vitamins A and C and the
mineral iron. The scientific name of
spinach is Spinacia oleracea.
Spinach is widely grown in northern
Europe and the United States. Growing
spinach requires cool weather and rich,
moist soil. Spinach is one of only a few
vegetables that can live through some
frost.
The spinach plant is an annual. This
means that it grows for only one season
and must be replanted each year. People
grow spinach to eat its leaves. Spinach
leaves can be either smooth or wrinkled.
They are roughly triangular in shape.
The leaves are clustered in a circle called
a rosette.
Spinach is sold fresh, canned, and frozen.
People eat it as a salad green or as a
cooked vegetable. It also can be used to
make soups and dips.
Spinach leaves are a source of the vitamins
that every person needs.
BRITANNICA STUDENT ENCYCLOPEDIA Spinach 165
Spiny Anteater
#see Echidna.
Spokane
The Spokane are Native Americans of
northeasternWashington State. They
traditionally lived along the Spokane
River. The city of Spokane,Washington,
was named after the tribe.
The Spokane hunted deer, elk, antelope,
and other animals. They also gathered
wild plants and fished, especially for
salmon. In the 1730s they were introduced
to horses. They used the horses to
hunt bison (buffalo) on the plains to the
east.
The Spokane built cone-shaped homes
made of pole frames covered with mats
or animal skins. They moved these
homes from place to place while on the
hunt. The Spokane also built larger,
rectangular houses in shallow pits.
By the early 1800s white settlers had set
up trading posts in Spokane territory. At
first the Spokane welcomed the newcomers.
But the tribe became angry as
the number of settlers grew. In 1858 the
Spokane joined the Coeur d’Alene and
other Native American neighbors in a
war against U.S. troops. The war is
known as the SpokaneWar or the Coeur
d’AleneWar. The Native Americans
were defeated. They had to give up some
of their land.
In the 1870s and 1880s the Spokane
agreed to settle on reservations. In 1881
the United States set up the Spokane
Reservation northwest of the city of
Spokane. At the end of the 20th century
there were about 2,000 Spokane living
in the United States. Many lived on the
reservation.
#More to explore
Coeur d’Alene • Native Americans
Sponge
Sponges are unusual animals that live in
water. They do not have the body parts
that most animals have. They do not
even move around. Instead sponges stay
attached to an underwater rock or coral
reef. For a long time people thought
sponges were plants. Scientists decided
that sponges are animals only after
watching them eat food by drawing it
into their bodies.
Three Spokane men display their weapons
in a photograph that was taken in the 1860s.
166 Spiny Anteater BRITANNICA STUDENT ENCYCLOPEDIA
There are nearly 5,000 different species,
or kinds, of sponge. Most live in the
ocean, but some live in freshwater.
Sponges can be flat like spreading moss.
Or they can look like trees with branching
arms. Some are as small as a bean,
while others are as tall as a person.
Sponges can be smooth and mushy, or
they can be rough, hard, and prickly.
Some are dull and drab, but others are
brightly colored.
A sponge’s body is a soft mass of cells
supported by a skeleton. Holes in a
sponge’s skin let water flow inside.
Sponges take food and oxygen from the
water. They do not have organs for
breathing, eating, and getting rid of
wastes. Each cell has to do these things.
Sponges are useful to people. People
collect sponges and then dry, clean, and
trim them. The fleshy parts are thrown
away, and only the skeleton is used. The
ancient Greeks and Romans used
sponges to pad their war helmets and
armor. People still use sponges for bathing,
mopping, and painting. However,
most of the sponges used today do not
come from animals. They are products
made in factories.
#More to explore
Animal • Ocean
Sports
A sport is a physical activity that people
