Origin of the species
Initially it was assumed that the polar bear separated from brown about 45-150 thousand years ago, probably in the territory of modern Ireland. However , a recent study showed that the polar bear separated from their common ancestor with brown bear 338-934 thousand years ago ( an average of 600 thousand years ago) , and 100-120 thousand years ago by crossing species representatives took their hybridization , resulting in all modern polar bears are descended from these hybrids .Appearance
Head bears. From left to right : Brown , Black, White .Polar bear - one of the largest terrestrial carnivorous mammals of Representatives . Its length is 3 m , weight up to 1 ton Usually males weigh 400-450 kg , body length of 200-250 cm, height at the withers 130-150 cm Females noticeably smaller ( 200-300 kg). The smallest bears are found on Spitsbergen , the largest - in the Bering Sea .Polar bear from other bears distinguish long neck and flat head . His skin is black. Fur color varies from white to yellowish ; summer fur may turn yellow due to constant exposure to sunlight . Polar bear fur is devoid of pigment stains, and hollow hairs . Translucent hairs allows only ultraviolet rays, giving the coat insulating properties . When ultraviolet photography polar bear seems dark . Due to the structure of the polar bear hairs can sometimes " go green ." It happens in a hot climate ( in zoos ) , when inside hairs infest microscopic algae .<span>Soles of the feet are hit wool, not to slip on the ice and not freeze. Between the fingers has a flipper and the front paws trimmed stiff bristles. Large claws can keep even a strong prey.</span>
Starting doing working finding going
1) Mr Grey must be visited (by them) in the morning
2) His cousin will be spoken to (by him) tomorrow.
3) She is often given fruits from their garden.
4) A new hospital was built last year.
5) A book is being read by her at the moment.
6) When Jack came supper was being prepared by his sister.
7) My homework is done. Now I can go for a walk.
8) His brother will be looked after by him next week.
9) The boy wasn't visited by pupils last week.
10) Poems aren't translated by us at home.
