Now there are posters that said prehistoric polar bears acctually shared the same habitat as wooly mammoths and rhinos and did not prey on the adults. However, what i have read is that barren grizzlies prey on must oxens twice their weight. Thniking about this, I am not about to say that a giant polar bear would regularly prey on adult wooly mammoths or rhinos but they could use thier advantage at night to prey on calves? Or maybe an aggressive female polar bear could chase mammoths or rhinos out of their territory to protect their cubs or an exceptionally aggressive male might acctually attack an adult wolly mammoth or rhino that ventures too close to its territory??? Any literature on that?
Not much is known about early polar bears (now there are reports of Irish ancestry) and I think people are getting ahead of themselves with some of the predator/prey speculation encounters. Anyhow, check out the following post which you might find interesting:
I have seen this video before and it might be a fairly accurate discription regarding the interaction. In this scenario, the polar bear sow was obviously eyeying the wooly mammoth herd a fair bit. However, none reacted aggressively towards the other, probably due to the healthy distance apart.