"Anything they want to."

But seriously, where do they get all the calories they need? From the numbers present at Quarry Junction, or the Promintory, it appears that each group would need to kill a Bighorner or several people each day. I suppose since they are highly modified from chameleons they could behave like land crocodiles, essentially dozing between big meals, but it still seems like the wasteland doesn't have enough food to support the packs we encounter.

Thoughts?

Lol you question the reality of wildlife in an elder scrolls game? Devs simply didn't think about it, just like they didn't think about it in Skyrim where you have 10 wolves on one deer ratio.