Horrors of the Hairy Frog

Today's guest is the Hairy Frog, Trichobatrachus robustus. This frog has a few things that make it rather unique. The most obvious is the hair, which frogs generally aren't supposed to have. Fortunately, it isn't really hair, just "threads of vascularised skin [grown] during mating season". I'll be honest, I don't exactly know what that means either.

But that isn't what really gets the Hairy Frog onto this page (even though it generally would be enough). No, it gets to join this page because of the trait that gets it its other common name, the Horror Frog. Now, a decent number of frogs have some sort of claws on their feet for defense. The Horror Frog doesn't. When it needs to defend itself, it actively breaks bones in its feet, then pushes the sharped, broken ends through its skin to use as makeshift claws. See the picture below.

According to newscientist.com,

At rest, the claws of T. robustus, found on the hind feet only, are nestled inside a mass of connective tissue. A chunk of collagen forms a bond between the claw's sharp point and a small piece of bone at the tip of the frog's toe.

The other end of the claw is connected to a muscle. Blackburn and his colleagues believe that when the animal is attacked, it contracts this muscle, which pulls the claw downwards. The sharp point then breaks away from the bony tip and cuts through the toe pad, emerging on the underside.

Here's a picture of the end result, from the outside.

Thanks to Cracked.com (NSFW/18+) for alerting me to this bizarre frog.

Tkrausse