Discovered frogs with feathers and sharpness

Harvard biologists (USA) are stunned to see many frogs with feathers and toenails that can be folded into.

Trichobatrachus robustus frogs have claws and feathers.Photo: Newscientist.

In fact, Trichobatrachus robustus - the scientific name of the bizarre frog - actively smashed their bones to create claws. The special thing is that these claws just protrude from the feet when they are threatened to defend themselves.

Biological expert David Blackburn and colleagues at Harvard University argue that the behavior is a defense mechanism of frogs. They had previously known that some amphibians "squeezed" the bones protruding out of the skin to create thorns, but had never witnessed self-crushing behavior to create claws. This behavior also occurs in 9 out of 11 species of frog species of Astylosternus in Cameroon.

Claws protruding from under frog feet.Photo: Newscientist.

'Some species of frogs have bone spines protruding from the limbs, but that is due to bone growth through the skin. Trichobatrachus robustus claws only protrude on the hind legs and are surrounded by tissues. "The collagen fibers bind the nails together and on each toe of the frog there is a small bone," David added.

The lower part of the nails is connected to a muscle bundle. David and his colleagues believe that when frogs are attacked, the muscle bundles shrink so that the nails protrude. Then the tip of the claw will escape from the tip of the toe with bone and pierce through the underside of the toe.

Claws separated from the leg bones.Photo: Newscientist.

Although it looks a lot like cat claws, the mechanism of this claw is completely different from that of all vertebrates. Another special feature is that the frog's claws are made of bones and there is no layer of keratin covering like other animals' claws.

Male Trichobatrachus robustus frogs with an average length of 11 cm also have hair on their skin. Experts say that these hairs allow them to take extra oxygen through their skin when they take care of their baby frogs. A Belgian zoologist named George Boulenger once discovered frog-like frogs first in 1900. in Congo, Africa.