Eh, I doubt that's the reason. This doesn't explain why they suddenly lose their fear of humans, even when facing considerable opposition.ngtm1r wrote:It's because we're easy to kill.
In other words, the first human might be easy to kill, but then all his friends hear about it and get angry. And yet the animal persists.
Uh, no. We're at the top of the food chain. We've used up nearly all the nutrients available.And nutrious.

This is why sci-fi stories about aliens needing people for food are so silly. They'd be much better off herding cows, which are strict herbivores and offer little resistance.