There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
Parvez says: I think it is because of big cats bears chose to be omnivores from their previous carnivorous nature. Big cats being proportionally muscled all over the body and with potentially higher stamina to fight for longer periods must have started to dominate them with both agility and smartness (or cunning nature). The bears must have got intimidated by the big cats. They understood that they cannot continue being carnivores (as cats have started to be dominant) or being scavengers of other's kills. They instead chose to be omnivores. *I say; this idea of big cats scaring bears into becoming omnivores is totally ridiculous. http://tolweb.org/treehouses/?treehouse_id=4728 The evolution of bears begins in the early Miocene era, approximately 20 mya (million years ago), when the first bear type animal named Ursavus elmensis evolved from a dog-like ancestor (Hitchcock, 2004). Fossil records from U. elmensis show carnassial teeth with larger molars for more chewing area, a trait common to present day bears. Another early bear in the lineage leading to grizzlies is Ursus minimus of the cave line bears, which lived in the Pliocene era, about 10 mya. The cave line bears persisted until the most recent ice age 10,000 years ago but then became extinct. However, roughly 1.5 mya a new lineage of bears diverged from the cave bear line. These bears, which were most similar to Ursus etruscus of the cave bear line, were the common ancestors of the brown bears, Ursus arctos, and the black bears, Ursus americanus. The closest relative of the brown bear is the polar bear, which diverged from U. arctos about 300,000 years ago. Brown bears have diverged into a large number of subspecies, one of which being the grizzly bear common to North America. http://news.nationalgeographic.com/news/2013/11/131112-big-cats-origin-tibet-animals-science/ Big cats may have originated in Asia as far back as six million years ago. *Therefore; bears were omnivores millions of years before the first big cat existed.