This video is called polar bear vs. walrus.
From Laura Klappenbach:
Fossil Jawbone Hints at Polar Bears‘ Past
Scientists have uncovered a fossilized jawbone from the sediments of an island in the Svalbard archipelago. The jawbone shares a convincing resemblance to that of a polar bear (Ursus maritimus). If it is indeed the remains of a polar bear, it represents the oldest known fossil record of the species. The research team, lead by Professor Olafur Ingolfsson from the University of Iceland, estimates the age of the fossil is at least 100,000 years old. This means the polar bear, thought to be a recently evolved species, has a longer evolutionary past than previously suggested.
The Svalbard Archipelago is a set of islands in the Arctic Ocean that lie approximately half-way between Norway (the country, incidentally, to which the Svalbards belong) and the North Pole.
Polar bears are thought to share a common ancestor with brown bears (Ursus arctos) and are believed to have diverged during the Upper Pleistocene (126,000–10,000 years before present). Yet the details of polar bear evolution remain obscure, as the fossil record is sparse when it comes to the polar bears of the past. This is in no small part due to their habitat. The remains of polar bears would likely be scavenged or sink to the bottom of the Arctic Ocean before they had a chance to fossilize. Genetic analysis of present day brown bears and polar bears has yielded solid evidence that the two species are closely related.
See also here.
Polar bear evolution: here.
DNA study clarifies how polar bears and brown bears are related: here.
July 2011: The female ancestor of all living polar bears was a brown bear that lived near present-day Britain and Ireland just prior to the peak of the last ice age – 20,000 to 50,000 years ago, according to an international team of scientists: here.