Some scholars think that he was a
schoolteacher. Others think that he traveled
with a group of actors.
Career in the Theater
By 1592 Shakespeare was working as a
writer and actor in London. In that year
a disease called the black plague devastated
the city. Officials closed the theaters
and other public places to stop its
spread. Shakespeare then turned to writing
poetry.
London’s theaters reopened in 1594. By
then Shakespeare had joined an acting
group called Lord Chamberlain’s Men.
They often presented plays for royalty.
Along with acting and writing, Shakespeare
also was involved with the business
side of theater. He became wealthy.
Plays
Shakespeare wrote 37 plays in 20 years.
His plays generally fall into three
categories: tragedies, comedies, and
histories. Tragedies are plays that
describe the downfall of the main
character. Shakespeare’s most famous
tragedies include Hamlet, King Lear,
and Macbeth. Comedies are humorous
plays that end happily. Shakespeare’s
comedies include A Midsummer Night’s
Dream, As You Like It, and The Taming
of the Shrew. Shakespeare’s histories are
dramas about some of England’s
powerful kings, including Henry IV
and Richard II.
Later Years
Shakespeare retired from the theater in
about 1610. He returned to his hometown
of Stratford-upon-Avon. He died
there on April 23, 1616.
#More to explore
Drama • Poetry
A collection of William Shakespeare’s
poems, printed in 1640, included a picture
of the author.
BRITANNICA STUDENT ENCYCLOPEDIA Shakespeare, William 75
Shamrock
A shamrock is a plant whose small,
green leaves are divided into three heartshaped
parts called leaflets. Shamrocks
are a symbol of Ireland, especially on
Saint Patrick’s Day.
Several different plants are known as
shamrocks. They include some members
of the pea family: white clover, small
hop or suckling clover, and black medic.
Wood sorrel is another plant called a
shamrock. The plants all grow in the
temperate, or mild, regions of the
Northern Hemisphere. Experts disagree
on which plant, if any, is the true Irish
shamrock.
In rare cases a shamrock leaf has four
leaflets instead of three. Finding a shamrock
with four leaflets supposedly brings
good luck.
#More to explore
Pea • Saint Patrick’s Day
Shark
Sharks are fast-swimming fish that have
a skeleton made of cartilage instead of
bone. (Cartilage is an elastic tissue that
is created before bone begins to form.)
They are related to rays. Sharks are
among the oldest animals on Earth. The
first sharks lived more than 300 million
years ago. Today there are more than
300 species, or types, of shark.
Where Sharks Live
Most sharks live in oceans in the mild or
warm parts of Earth. But the Greenland
shark lives in the cold Arctic waters.
Sand sharks spend most of their time at
the bottom of shallow water. The Portuguese
shark lives in the deepest parts of
the ocean.
Physical Features
The whale shark is the largest living fish.
It can reach about 50 feet (15 meters)
long and weigh nearly 20 tons. The
smallest shark is the dwarf lantern shark,
which is only about 7.5 inches (19 centimeters)
long.
Several different plants that have three-part
leaves are sometimes called shamrocks. The
redwood sorrel is one such plant. It grows
in the redwood forests of western North
America.
Sharks move restlessly to keep from sinking
to the ocean floor.
76 Shamrock BRITANNICA STUDENT ENCYCLOPEDIA
Most sharks have a pointed snout that
extends forward over the mouth.
However, hammerhead sharks have a
wide, flat head. A shark’s teeth are
sharp and triangular and grow
throughout its life. Only a few species,
including the white shark, the tiger
shark, and mako sharks, have very large
teeth. Sharks have a muscular, upturned
tail and pointed fins.
Sharks normally have tough, gray skin
with toothlike scales. Their skin also
may be cream, yellow, brown, bronze,
blue, or nearly black in color. They often
are patterned with spots, bands, or marbling.
Behavior
Sharks use their sharp sense of smell to
find food. They may eat plankton, shellfish,
sea turtles, fish, seals, porpoises,
squid, or whales. Sharks circle their prey
and frequently approach from below.
When excited by the smell of blood,
sharks may have a “feeding frenzy.” This
means that they attack any object within
reach and feed rapidly.
Sharks swim constantly to keep from
sinking. They are known for their speed
in the water. Most species can swim 20
to 30 miles (32 to 48 kilometers) per
hour. But the speed of mako sharks has
been recorded at more than 60 miles (97
kilometers) per hour.
Most sharks live by themselves. But a
few, such as the spiny dogfish shark,
form schools, or groups.
Reproduction
Sharks reproduce in one of three ways.
In some types the female gives birth to
live young. In other types the young
hatch from eggs inside the female’s body
and then are born. In still other types
the female lays rectangular, leathery eggs
that become attached to rocks or seaweed.
The young hatch days or weeks
later. Female sharks may have from 2 to
about 20 young at a time.
Sharks and Humans
People eat the meat of some sharks,
including thresher and mako sharks.
