Well, bears are classified in the order Carnivora, so plenty of sources say that's it, they're carnivores. But if you look at their teeth and diets, it's fairly obvious that they're evolving towards being omnivores. Ursus americanus, which are the bears I know most about due to following the daily Bear Research Updates, basically don't eat meat. They get their animal protein from sources like termites, ant brood, and bee larvae, topped up by occasional fish at the right time of year.
Even polar bears, which you'd think of as "true" carnivores, eat a fair bit of plant matter - especially in summer & when starving. Wikipedia claims that some biologists think their dentition shows they have evolved from pure carnivores to omnivores & are now going back to carnivores again, but if a source was given I didn't see it. Mind you, the whole theory of where exactly polar bears came from is controversial (most recent claim iirc is that they evolved from grizzlies, which is why they can so easily cross-breed with grizzlies to make "grolar" bears), but how many thousands of years ago is debatable from 10 to 50 - that's a big difference in evolutionary timescales!
![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
timeasmymeasure
no subject
Date: 2012-10-11 11:29 am (UTC)Even polar bears, which you'd think of as "true" carnivores, eat a fair bit of plant matter - especially in summer & when starving. Wikipedia claims that some biologists think their dentition shows they have evolved from pure carnivores to omnivores & are now going back to carnivores again, but if a source was given I didn't see it. Mind you, the whole theory of where exactly polar bears came from is controversial (most recent claim iirc is that they evolved from grizzlies, which is why they can so easily cross-breed with grizzlies to make "grolar" bears), but how many thousands of years ago is debatable from 10 to 50 - that's a big difference in evolutionary timescales!