"The original function of the primordial 'hair keratins' as 'toe keratins' is conserved in toe pads of tree frogs, toe tips of the axolotl [and] claws of clawed frogs," the team writes in their paper.

According to the study, Xenopus frogs' cornified claws are made of unique proteins called keratins, which are strikingly comparable to the major elements of mammalian hair and nails. It was discovered ...