Britannica Student Encyclopedia - 2010

There are about 80 species, or types, of whale. The blue whale is the largest of all.

BRITANNICA STUDENT ENCYCLOPEDIA Whale 37

 

pilot whales. Dolphins and porpoises

also belong to this group.

There are about 10 species of baleen

whale. These include the blue whale,

the gray whale, the fin whale, the

humpback whale, the sei whale, and

right whales. Baleen whales do not have

teeth. A baleen whale feeds either by

swimming with its mouth open or by

gulping water. A series of filters in the

mouth called baleen acts as a strainer.

The baleen lets water out but holds in

small fishes, shrimps, and other

creatures.

Where Whales Live

Whales live in oceans and seas all over

the world. Some species can be found in

rivers. Large species often migrate, or

travel from one place to another, at certain

times of the year. Some types travel

thousands of miles.

Physical Features

Whales are generally more than 10 feet

(3 meters) long. Several species, mainly

baleens, may be 60 feet (18 meters)

long or more. The blue whale is the

largest animal that has ever lived. It

may be more than 100 feet (30 meters)

long.

Whales are usually black, gray, black and

white, or white. Some types are bluish

gray. A whale’s skin is smooth. A thick

layer of fat, called blubber, beneath the

skin protects the animal from cold

water.

A whale’s torpedo-shaped body helps it

to move quickly through the water. It

pushes its tail up and down to move.

The tail is divided into two broad sections

called flukes. These extend horizontally

(side to side) instead of

vertically (up and down), as the fins of a

fish do. A whale also uses two flippers

on the front of its body for steering.

Whales go to the surface of the water to

breathe. A whale takes in air through

one or two openings, called blowholes,

on the top of the head.

Behavior

Many kinds of whale, especially toothed

whales often can be found in groups

called schools or pods. These groups

can range in size from a few animals to

more than 1,000. Baleen whales are

more likely to live alone or in small

schools.

Whales make many sounds—including

whistles, barks, and screams—to

communicate with other whales.

Toothed whales also make special

sounds to locate objects they cannot

see. These sounds bounce off solid

surfaces and travel back to the whale’s

sensitive ears. This process is called

echolocation.

Life Cycle

About one year after mating, a female

whale gives birth to a single baby, or

calf. She nurses her calf for a number of

months. Some types of whale may live

for 100 years or longer.

#More to explore

Dolphin • Fish • Mammal • Porpoise

For many

years people

hunted whales

for the oil in

their blubber.

People used

whale oil as

fuel and to

make soap.

Today whale

hunting is very

limited.

38 Whale BRITANNICA STUDENT ENCYCLOPEDIA

 

Wheat

Wheat is a very important grain. It is a

major source of nutrients for people.

More of the world’s farmland is devoted

to wheat than to any other food crop.

Wheat belongs to the grass family.

People first grew wheat as early as 9,000

years ago in the Middle East. Today

China, India, and the United States are

leading wheat producers.

There are thousands of kinds of wheat.

Wheat plants grow to between 2 and 5

feet (0.6 and 1.5 meters) tall. Most types

have a hollow stem. At the end of the

stem is a structure called a head, or

spike. The spike is made up of 20 to 100

tiny flowers. These flowers produce the

seeds, or kernels, of wheat. Wheat kernels

vary in color depending on the type

of wheat. Some are dark reddish brown.

Others are brown, tan, white, cream, or

yellow.

Farmers harvest wheat using a machine

called a combine. The combine cuts

down the plants. Then it separates the

seeds from the rest of the plants.

Most wheat is used to make food for

people. Whole or coarsely chopped

wheat kernels are cooked and used in

cereals and soups. But wheat is more

commonly used in the form of flour. To

make flour, the kernels are cleaned and

then crushed into tiny pieces. Wheat

flour is used to make bread, cakes,

crackers, cookies, and pasta.

Wheat is also used to feed livestock. The

dried plants are used as straw for animal

beds.

#More to explore

Grain • Grass

Wheatley, Phillis

Phillis Wheatley was the first African

American to write a book. Her book of

poetry was published in 1773. Wheatley

proved to many people that blacks were

equal to whites in creative ability.

Phillis Wheatley was born inWest

Africa. Her date of birth and her African

name are not known. A slave ship took

her to Boston, Massachusetts, in 1761.

She was then about 8 years old. A

couple named John and Susanna Wheatley

bought her. They gave her their own

last name.

Wheatley quickly learned to speak, read,

and write English. In 1767 a newspaper

Golden spikes of wheat are ready to harvest.

BRITANNICA STUDENT ENCYCLOPEDIA Wheatley, Phillis 39

 

published one of her poems. Three years

later Wheatley wrote another poem to

honor a clergyman named George

Whitefield. The poem was published

throughout the North American colonies

and in England. Wheatley became

famous.

By 1772 Wheatley had written enough

poems to fill a book. Susanna Wheatley

helped Phillis to publish the book in