Species evolve in the most astonishing ways! That idea was reinforced for me recently when I was rereading Greg McDonald’s thesis and stumbled across a note about Megalonyx teeth that I hadn’t caught previously. I’ve written before about sloth teeth and the error of assuming differences between sloths and other mammals are evidence they were inept or stupid and maladapted. Some remarkable mammals owe much of their success to abandoning the “normal” patterns of the so-called “higher” mammals and following the path of ground sloths. Greg cites an amazing example . . . as my generation would say, the implications are mind-blowing! (image borrowed from)
So here’s the challenge: There’s a living mammal with teeth that bear a remarkable functional resemblance to those of Megalonyx (excluding other Xenarthrans). That is, its teeth are made up entirely of dentin wrapped in a layer of cementum, and as in sloths they are self-sharpening and ever-growing. What animal is it and what special advantage does this adaptation give it to survive in its unique niche?