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

Megatherium americanum is the scientific name for an extinct species of giant ground sloth. The name means ‘great beast from America’. But despite these creatures stretching up to 4.6 metres (15 feet) and weighing roughly 2,590 kg (5,709 pounds), a single ground sloth would have spent much of its lifespan dedicated entirely to constructing tunnels as large and extensive as these palaeoburrows are. So why bother?

Frank and his team are unsure whether the extensive caverns were used to escape the climate, predators, or humidity, but then even those explanations seem unlikely. After all, a much smaller burrow would have suited those purposes just fine, wouldn’t it?

Could it be that several individuals inherited the burrows over generations, and kept adding to the structure to make it so enormous. Again, that’s something the researchers will need to confirm through further observations.