The largest ever rodent used its huge incisors like elephant tusks, digging for food and defending itself from predators, scientists say.

The giant relative of the puny guinea pig, which went extinct around two million years ago, weighed more than 2,000 pounds and was similar in size than a buffalo. Josephoartigasia monesi was native to South America and had a pair of powerful, foot-long incisors.

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The current largest living rodent, the capybara, weighs a paltry 145 pounds.

Dr. Philip Cox of the Centre for Anatomical and Human Sciences at the University of York scanned a fossil skull of J. monesi. The computer modeling suggests its bite was as strong or even stronger than that of a modern tiger. Its front teeth almost a foot long could withstand forces as much as three times as large.

The specimen is missing its lower jaw, but is otherwise distinctive for its fearsome giant front teeth. Using a process called finite element analysis, researchers were able to measure how the skull would react to pressure in real time.

Cox found that Josephoartigasia had a bite force of 1,400 newtons - comparable to that of a tiger. Cox suggests the mammoth rodent's teeth could withstand three times more pressure than its own bite force.

"These results, combined with previous work, lead us to speculate that J. monesi was behaving in an elephant-like manner, using its incisors like tusks, and processing tough vegetation with large bite forces at the cheek teeth," they said.

J. monesi, the largest rodent ever discovered, lived during the warm Pliocene period when large mammals such as the first mammoths were fairly abundant.

They're sometimes called the giant pacarana after its closest living relative, the pacarana.

Details of the largest rodent discovery were published in the Journal of Anatomy.

Tagsrodent, ancient rodent, largest rodent, Josephoartigasia monesi, animal fossil, predators, Pliocene period