South America is known as home to some of the world's smallest (and cutest) animals, like the world's smallest anteater, the silky anteater, and Earth's smallest monkey, the pygmy marmoset. But the continent once hosted the world's largest rodents.

New research suggests these massive mammals likely used their giant front teeth as a defensive mechanism and as a tool for digging. Scientists say the Josephoartigasia monesi -- a guinea-pig like mammal the size of a buffalo -- used its incisors like elephants and rhinos use their tusks.

Researchers were able to draw conclusions about the ancient mammal's behavior after studying a newly unearthed fossil, which was dated to three million years ago. Lab scientists used CT scans and other imaging techniques to measure the physical capabilities of the two front teeth.

The numbers showed the rodent could chomp down with a force of 1,400 Newtons, similar to a tiger, but the front teeth could withstand 4,165 Newtons -- roughly three times as much force.

"We concluded that Josephoartigasia must have used its incisors for activities other than biting, such as digging in the ground for food, or defending itself from predators," Philip Cox, a researcher at the University of York, said in a press release. "This is very similar to how a modern day elephant uses its tusks."

The analysis of Josephoartigasia and its impressive front teeth was published in the Journal of Anatomy.