Page 30 - Shark

The great white shark

Dorsal
A powerful predator, the great white inspires fin
French landing
fear. This awesome shark grows to over 20 ft (6 m) long This old engraving of a great white
and weighs more than 2.2 tons. It is the largest of the landed on France’s Mediterranean
predatory sharks, capable of eating sea lions whole. coast shows how a century ago
people were also fascinated by
sharks. Unless they were lucky
The great white became famous in the Jaws movies, enough to see sharks first hand,
where it appeared as a blood-thirsty creature intent on artists had to rely on descriptions
to make their drawings since
killing people. Attacks (pp. 48–49) on people are rare, there were no photographs. There
and possibly occur when a shark mistakes a are several inaccuracies in this
person for its usual seal prey. Scientists are engraving—the artist has given the
great white the tail of a thresher
learning more about the great white, which and gill covers, like bony fish, as
is rare and on the decline in some oceans. Small second well as gill slits.
dorsal fin,
Sharks are often studied around seal compared to
size of first
colonies. It is thought that great dorsal fin
whites may interact with
one another, slapping
their tails against
the water to
ward each
other off. Pelvic fin

Front view of
model of a great
white shark
Swimming
keel
Long snout

Upper and
lower lobes
of caudal fin
are almost Relatively
symmetrical small anal fin Clasper
(pp. 16–17)
Warm blood
Great whites and their relatives—the mako,
thresher, and porbeagle—are all warm-blooded,
which means that they are able to keep their body
temperatures higher than the surrounding water. Only
mammals, birds, and a few fast fish, like the tuna, are
warm-blooded. These sharks have blood vessels in their
muscles arranged in complex nets, so that the warm blood
leaving the muscles passes heat to the cool blood coming
from the gills (pp. 10–11). A high body temperature means that
great whites have warm muscles that are able to act fast. This is
important for a predator that has to make a high-speed dash to catch
its prey. Being warm-blooded may also help the great white to digest its
food more quickly. Scientists estimate that after a big feed a great white can
last three months before needing another meal.

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