Scientists at the University of York and The Hull York Medical School have found that the largest rodent ever to have lived may have used its front teeth just like an elephant uses its tusks.

Josephoartigasia monesi, a rodent closely related to guinea pigs, lived in South America approximately 3 million years ago. It is the largest fossil rodent ever found, with an estimated body mass of 1000 kg and was similar in size to a buffalo.

Researchers, led by Dr. Philip Cox of the Center for Anatomical and Human Sciences used computer modeling to estimate how powerful the bite of Josephoartigasia could be.

They found that, although the bite forces were very large -- around 1400 N, similar to that of a tiger -- the incisors would have been able to withstand almost three times that force. This information is based on earlier estimates by co-authors Dr. Andres Rinderknecht of The Museo Nacional de Historia Natural, Montevideo and Dr. Ernesto Blanco of Facultad de Ciencias, Instituto de Fisica, Montevideo, who first described the fossil in 2008.

"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. This is very similar to how a modern day elephant uses its tusks," Cox said.

The research, which is published in the Journal of Anatomy, involved CT scanning the Josephoartigasia monesi specimen and making a virtual reconstruction of its skull. This was then subjected to finite element analysis, an engineering technique that predicts stress and strain in a complex geometric object.