4th February 2016
Newsademic.com
™
- British English edition
page
10
There are two types o f large
whales: baleen and toothed whales.
Baleen whales have comb-like fil
ters, or baleen plates, along their
upper jaws. Even though the whales
are huge,
they eat tiny shrimp-like
sea creatures called krill. Baleen
whales take in big mouthfuls of
water. This is pushed out through
their baleen plates. The krill in the
water are too big to pass through the
filters. They remain in the w hale’s
mouth and are swallowed. The blue
whale is the w orld’s biggest animal.
It is a baleen whale.
Sperm whale
The
sperm whale is the largest
toothed whale. It has a row o f large,
pointed teeth around the lower jaw.
W hen the whale closes its mouth, its
teeth fit into holes, or empty sock
ets, in the upper jaw. Sperm whales
mainly eat squid. They also feed on
some types o f fish and octopuses. A
sperm whale eats at least 400 squid
every day.
Sperm
whales are found in most
of the w orld’s oceans. Adult males
can be 20.5 metres (67 feet) long.
The head makes up about one-
third o f the w hale’s body. O f all the
w orld’s animals, the sperm whale
has the biggest brain. It weighs about
7.8 kilograms (17 pounds). This
is more than five times the weight
o f an adult human brain. Sperm
whales usually live for more than 70
years. Females stay in groups called
pods. They look after their off
spring,
or calves, for over ten years.
Fully-grown males are solitary.
They live on their own.
The w hale’s name comes from a
liquid, white waxy substance in the
upper part of its head. It’s called
spermaceti. Scientists are not sure
what it’s for. Some believe that
the
substance controls buoyancy,
or how the whale floats. Oth
ers think it has something to do
with echolocation. This is a type
o f sonar. The whales make noises.
They then listen for the echoes the
sounds make. The animals then use
the echoes to work out an image of
their surroundings.
Years
ago spermaceti was very
valuable. It was used to make can
dles. Spermaceti oil was burnt in
lamps. In the 1700s and early 1800s
hundreds of whaling ships set sail
every year. Many thousands o f sperm
whales were hunted and killed for
their spermaceti. In the 1850s kero
sene (also known as paraffin) was
invented. At first, it was made from
either coal or oil. Kerosene replaced
spermaceti wax and oil.
Sperm whales prefer deep waters.
They can dive to depths o f 1,000
metres (3,280 feet).
The whales
must come to the surface to breathe.
On deep dives, sperm whales hold
their breath for 90 minutes. Many
sperm whales live in the North At
lantic Ocean. Normally, they do not
enter the North Sea. This is because
it is too shallow.
Scientists
say that the dead
whales found on the North Sea
coasts belonged to the same pod.
They may have been chasing squid.
After swimming into the North
Sea, the whales probably became
confused. They got stuck in shal
low waters. Winds and waves then
washed them onto the shore. □
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