Unknown The Trichobatrachus robustus frog breaks its own bones to form claws when threatened image:40884:2::0

Time and time, again, I am astounded by the insane creations that nature has produced. And it seems to have done it again, this time with bone-breaking frogs.

As the New Scientist reports:

Trichobatrachus robustus actively breaks its own bones to produce claws that puncture their way out of the frog's toe pads, probably when it is threatened.

While other frogs have rigid spines that project out from their wrists, this breed is different in that the claws, which are only in the hind legs, can be 'sprung' outwards, and don't seem to have any muscular connections to pull them out or back in.

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.

Because there is apparently no muscles to retract the claws after use, the biologists believe that the claws naturally slide back into the toe pads when the muscles surrounding it relax. However, this cannot be confirmed because they have not studied any live specimens, only dead.

The frogs, which are native to Cameroon, are frequently eaten by the locals, who hunt the amphibians with spears and machetes to avoid having the claws hurt them. The claws themselves are unique from other breeds of frogs, particularly in that it is believed they heal over and the tissue regenerates (allowing use of the claws again).

The biologists also highlight the need to increase research funding on amphibians, particularly considering how the changing climate is threatening to create mass extinctions of the frogs (among others).

To me, this looks like evolution in action; the frogs are developing more sophisticated defence mechanics, which given the dire situation that's encroaching upon their lives and survival, will hopefully give them another advantage. I just wonder, that if it is a defence system, what's attacking them that is small enough to be susceptible to the claw's piercings?