@Roberta,
I think my fascination with the extraordinary toughness of some animals (and insects) started long ago - when I started trying to figure out more about some of the creatures that my comic-book heros (and villains) were designed based on.
Hope y'all don't mind - here are some details about those two little bad-asses in my previous post:
A member of the weasel family, the honey badger has few natural predators because of its thick skin and ferocious defensive abilities. Their eyes are small, and their ears are little more than ridges on the skin; possible adaptations to avoiding damage while fighting.
The feet are armed with very strong claws, which are short on the hind legs and remarkably long on the forelimbs. Honey badgers are notoriously fearless and tough animals, having been known to savagely attack their enemies when escape is impossible. Bee stings, porcupine quills, and animal bites rarely penetrate their skin. If horses, cattle, or Cape buffalos intrude upon a honey badger’s burrow, it will attack them. They kill and eat snakes, even highly venomous or large ones such as cobras. They have even been known to dig up human corpses in India.
http://en.wikipedia.org/wiki/Honey_badger
The wolverine has a reputation for ferocity and strength out of proportion to its size, with the documented ability to kill prey many times its size. It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids (weasels).
They have thick, dark, oily fur which makes it resistant to frost. Wolverines, like other mustelids, possess a special upper molar in the back of the mouth that is rotated 90 degrees, towards the inside of the mouth. This special characteristic allows wolverines to tear off meat from prey or carrion that has been frozen solid. They have been recorded killing prey such as adult deer that are many times larger than itself.
There is at least one published account of a 12 pounds (5.4 kg) wolverine's apparent attempt to steal a kill from a black bear (adult males weigh 400 to 500 pounds -180 to 230 kg).
http://en.wikipedia.org/wiki/Wolverine