Biggest Rodent - Researchers say the largest rodent that ever lived weighed around 2,200 pounds (1,000 kg), and used its large front teeth the way elephants use their tusks - not just for biting food, but for digging and defense.

The biggest rodent, Josephoartigasia monesi, is roughly the size of a buffalo; estimated at 1.5m tall and 3m long. It's closely related to guinea pigs.

The skull of the largest fossil rodent ever discovered was unearthed in Uruguay in 2007.

Reports indicate that the biggest rodent lived around 2 million years ago in South America, in the Pliocene period - during which other large mammals thrived.

The study was recently published in the Journal of Anatomy by researchers from York in the UK and Montevideo in Uruguay.  They arrived at the conclusion after CT scanning Josephoartigasia monesi's skull and subsequently reconstructing a computer model of it to include its missing lower jaw, which they copied from a 3D scan of its closet living relative- the plains viscacha.

Researchers discovered that the biggest rodent's bite was very large - around 1400 N, and very similar to a tiger's. Additionally, its incisors would have been able to resist three times that force.

"We concluded that Josephoartigasia monesi must have used its incisors for activities other than biting, such as digging in the ground for food, or defending itself from predators," said Philip Cox of the Center for Anatomical and Human Sciences at the University of York.

"This is very similar to how modern day elephants use its tusks."

Cox added that the biggest rodent's chisel-like teeth "could resist much greater forces than could be generated by the masticatory muscles."

According to reports, researchers tested their findings by using 'finite element analysis,' an engineering technique used to calculate strains and stresses in complex objects.