Page 146 - World of Animals - Book of Sharks & Ocean Predators

Sharks & Ocean Predators
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Arctic Colourless hair Little ears and tail
Having smaller extremities conserves heat and small
The outer layer of a bear’s fur is
ears and tail lie close to the body. This doesn’t affect
adaptations actually colourless – these hairs their function though – they have very acute hearing!

are hollow and reflect visible light
in their empty space, which makes
the bear look white and provides a
Polars are kitted to the brim with tools handy camouflage for hunting.

to tackle the harsh environment
The polar bear’s adaptations to deal with
the cold go beyond their furry outward
appearance. Polar bears have evolved to
have reinforced heart muscle that fi ghts
against vascular disease, much more
so than their grizzly bear relatives. A
strong heart helps pump warming blood
around the body, which is insulated by
more than thick fur. A polar bear’s skin,
bone marrow and the space between
organs is packed with adipose fat that
is bursting with stored energy. This
specialised fat can make up over 50 per-
cent of the polar bear’s body weight and
keeps their body functioning properly
despite the bitter cold.
Polar bears often have to fast when
food is scarce or when raising cubs, so
this energy store is essential to their
survival. These bears can even control
the activity of their cells to raise their
body temperature. Nitric oxide found in
the body converts nutrients from food
into energy, but polar bears can opt
to convert ingested nutrients directly
into heat by controlling the level of
nitric oxide in their cells. Every part of
a polar bear’s body can be used as
Thick blubber
a weapon against the cold, and their
Black skin A ten-centimetre layer of
unbelievable adaptations to dealing with fatty blubber just under the
Beneath the white fur, a polar
plummeting temperatures are still not bear’s skin is actually black. skin acts as an insulator. It
fully understood. This helps to absorb the Sun’s also provides buoyancy in
As polar bears grow they’re able to rays and retain the heat. White the water to save energy

skin that would reflect heat off when swimming.
eat a more varied diet of larger animals.
the bear’s body.
Older bears eat enormous harp seals
and even beluga whales to sustain their
bulk. Males can grow to double the size
Furry feet
of females, and the bigger they get the The bottom of a polar bear’s paws
more they need to eat to keep their is covered in fur. This helps to
temperature up. The stomach can hold insulate and provide grip. Traction Super-sized paws
for charging about on the ice is also

20 per-cent of their body weight, which Huge oar-like paddles for paws are efficient and energy-
provided by small bumps on the saving when swimming, and spread the bear’s weight
is 700 kilograms (300 pounds). That’s pads, known as papillae. while on the ice. Strong, sharp claws help to grip.
the equivalent of an average human
eating 1550 loaves of bread!
The bear family
A glance at the biggest bears in the business
1 metre
American black bear
Giant panda Ursus americanus
Ailuropoda melanoleuca Sun bear Length: 1.8m
Length: 1.5m (plus 0.2m tail) Helarctos malayanus Shoulder height: 1m
Shoulder height: 1m Length: 1.2m Amount left in wild:
Amount left in wild: 1,400 Shoulder height: 70cm 850,000-950,000
Amount left in wild:
no reliable data

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