Male hairy frogs produce strange masses of arteries and skin when they are breeding. These snarls of gross yuck appear on external parts of their bodies and look like hair. They seem to have some connection with the biological function of breeding. However, it is uncertain what that connection is. Scientists who study hairy frogs have postulated that they may be mechanisms to increase oxygen intake during breeding time. It may also be to help them breathe underwater.
The second bizarre attribute of hairy frogs is what got them the epithet "horror frogs." These frogs have claws on their back feet that look like cat claws. However, it appears that they are very different. When the frog has need of these claws, bones break and release the claws, which puncture the skin on their way out. Furthermore, they are purely bone, which cat claws are not.
Unfortunately, at this time, frogs are going through mass extinctions. Thus far, no one has come up with a plan to stop it or even a reason that it is happening on such a large scale. If we want to study hairy frogs further to find out why they have these strange features, we have to protect them. Just how we are going to do that is anyone's guess.
"Horror Frog" Breaks Own Bones to Produce Claws, retrieved 5/23/11, newscientist.com/article/dn13991-horror-frog-breaks-own-bones-to-produce-claws.html