One big rodent
You'd be hard-pressed to find a chair big enough on which to jump and escape this fellow. Standing five-foot at the shoulders and weighing almost a ton, it was the largest rodent ever to scuttle across the earth and 14 times bigger than any alive today.
It lived in the forests of South America four million years ago,dodging attacks from giant meat-eating birds and sabre-toothed tiger cats. According to the scientist who have examined its skull, it looked like a cross between a guinea pig and a beaver.
The broken skull was found in a boulder which fell away from a cliff in the San Jose region of Uruguay and was stored for many years in the Montevideo national history museum without anyone realising its importance.
It was only when the museum's fossil expert Dr Ernesto Blanco took a close look that he discovered it belonged to a creature never seen before.
Dr Blanco-who named the animal Joseph part I gas is monesi -calculated that it weighed around a ton, or 157 stone.
"We only have the skull,so its not possible to be certain,but looking at the large rodent,I guess that it was three metres long from the tip of its nose to the end of its very short tail," he said.