Bears of the Pleistocene

[tigerluver]

In most paleontoligical cases, the sample size from which conclusions are drawn from are normally very small. I'd stray away from calling such conclusions are invalid when there are no better options. 

Sure, bears may could get bigger, a few fossils doesn't tell enough, I agree.

Although, I would like you to understand that I am thinking under Hutchinson, Grinnel, Elton, etc. niche principle.

You're mammoth carcass idea. Ignoring the fact of resource depletion, that carcass will potentially attract all the aforementioned competitor predators. The American lion, a pack of dire wolves, Smilodon, and certainly Arctodus are massive hurdles blocking access to the carcass (this is interference competition). There's not as much available as one would like to think.

Moreover, often one predator is capping the size of the other. There are a lot of Pleistocene predators that can size cap the brown bears of that age.

The reality of the situation is still much more complex than this. Maybe some other factor not discussed here allowed the bears to grow the modern coastal sizes. Maybe time will change the status quo. Reply