Sharks have been around for a very
long time. They can be big or small and
they come in lots of different shapes.
Many sharks are shy and harmless.
Only a few sharks will attack a person.
The body of a shark is smooth and
long. Sharks have strong tails that help
them swim quickly.
Their skin has thousands of little scales.
These scales are called denticles and
they all point to the tail of the shark
They will rip anything that rubs up
against them.
Sharks have lots of teeth. The teeth are
different shapes, according to the job
they have to do. Some are sharp and
pointed and some are flat for crushing
things. Sharks have several lines of teeth.
If a tooth falls out, another one fills the
gap!
The fin on the back of a shark is called
the dorsal fin. It is this fin that you
think of, sticking up out of the sea,
when you think of a shark.
Sharks do sometimes attack surfers and
swimmers. This could be because the
sharks think they look like the seals and
turtles they normally eat. Look at the
shape of a surfer, a seal and a turtle
from underneath.
One of the biggest fish in the sea today
is a shark: the whale shark. It can grow
to 12m long. A whale shark does not
have any teeth. Instead, it has filters to
catch plankton. It swims along with its
mouth wide, and the plankton float in
and are trapped.
There are often black and white striped
fish swimming by
the whale shark's
mouth. These are called remoras and
they help the whale shark by eating
small animals off the body of the shark.
Sharks have very good senses. They can
smell food from a long way away. They
have sensors on their snouts that pick
up electrical signals that other fish and
animals send out.
The hammerhead shark has a very oddly
shaped head. No one knows exactly
why the hammerhead has this shaped
head. It swings its head from side to
side to sense the things around it.
Sharks have to keep swimming, or they
sink
So they have to swim all the time,
even when they are asleep!
The biggest shark that ever lived was
called megalodon. It lived a very, very
long time ago. No one knows exactly
how big a megalodon was, but it would
have been enormous.
Some sharks, like the dogfish, lay eggs.
The outside case of the egg is leathery.
The case attaches itself to seaweed by
twisted strands, until the egg hatches.
You often see them lying on the beach.
Sometimes they are called mermaid's
purses.
The thresher shark has a very long,
curved tail. The tail is as long as the
head and the body together. It flicks its
tail from side to side as it swims around
a shoal of fish. The fish end up in a
tight ball, which makes it easier for the
shark to catch them.
The wobbegong belongs to the shark
family. It has frilly bits of skin hanging
across its mouth. It lies in wait on the
bottom of the sea and when animals
and fish investigate the frill, the
wobbegong snaps them up.
It is difficult to see it on the bottom
because of the pattern on its skin
Rays belong to the same family as
sharks. They are flat fish with wings,
which they flap as they swim along.
The stingray is so called because it has
a poisonous spine or
"sting"
on its tail.
Hammerhead sharks hunt stingrays. The
poison in the stingray's tail does not
affect the sharks.
Man is the shark's biggest enemy. Some
beaches have nets put around them to
keep sharks out. Lots of sharks are killed
in the nets. The sharks get tangled in the
nets and drown, as they cannot swim.
Men kill many more sharks than sharks
kill men.
https://drive.google.com/file/d/1XLs7TPsNxrMZ-3_ZPxyu03v04TXGlj1G/view?usp=drivesdk You can download this PDF file there 👆
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