A giant mammal that lived 10,000 years ago in Brazil dug gigantic tunnels called “palaeoburrows”. And digging those tunnels required claws. Huge ones.

Looking into a large paleoburrow in Brazil. Image credit: Heinrich Frank
So far, Frank and other researchers haven’t found fossils inside the caves, nor organic material or mineral deposits that could help more precisely date the exact creation of the burrows. But the quest continues.