Years ago I put a half-grown rabbit in my cage that had a couple pythons in it. No one seemed to care at the time, and 3 days later the rabbit was still alive. I dropped a week-old chicken in, and the rabbit immediately ran over and grabbed the chick in it's mouth, then ran back to it's corner. I removed the chick.

I've always like the fact that rats and mice have tails that are convenient for "thumping". Tried that with a gerbil once. The gerbil went flying across the room, while all that remained in my hand was something that resembled a small, fuzzy, brown condom.

Ok, very small.