Ursus maritimus tyrannus (Latin for tyrant sea bear) was recognized as the first subspecies of polar bear in 1964 by Björn Kurtén. Fossils were found at the gravels of the Thames at Kew Bridge, London, England. It is believed to have evolved between 250,000 and 100,000 years ago when a large number of Siberian brown bears became separated by glaciers.

HABITAT

The habitat of the early polar bear started out as far south as England and the northern coast of Spain. As they moved farther and farther north, they adapted to the harsh environment of the Arctic.

CHARACTERISTICS

Tyrannus was markedly larger and more Arctos-like than the present polar bear. Their bone structure was similar to that of brown bears only much larger. They measured about 6 feet at the shoulder, over 12 feet in length, and weighed on average over 2,500 pounds making it the largest carnivorous land mammal ever.

DIET

Though the diet of this early polar bear isn't really known, one can probably assume that it started out pretty much like that of the Siberien brown bear, and became more and more like that of the modern polar bear, adopting a more specialized and carnivorous diet. Its size and strength would have allowed this bear to take down large animals like buffalo and woolly mammoths. However, it would have also been capable of running any predators away from their kill, allowing it to be a scavenger.