Mole senses

Abstract

Many people are familiar with the meandering tunnels of moles, far fewer are familiar with the creatures that made them. Such secrecy is, of course, one of the great benefits of burrowing through the earth where few predators can follow. But it's not the only benefit. Soil contains a smorgasbord of nutritious invertebrate prey - hence all the tunneling. In fact the richness of the soil niche has given rise to a diversity of mole species that could be said to resemble the evolutionary diversification of bats, though on a smaller scale. In both cases, mammals have evolved a suite of unique anatomical traits (coincidentally involving modification of the forelimb) that allows them to exploit a huge resource of invertebrate prey that is largely inaccessible to their competitors. For bats the thin, delicate wings were the key innovation, for moles the forelimbs have undergone a similarly dramatic structural shift, but in the opposite direction - the bones have become short, stout, and powerful to act as shovels.