Researchers from the University of York and The Hull York Medical School (HYMS) have learned that the largest rodent known to have ever walked on Earth may have used its front teeth like a tusk to protect itself and find food.
A relative of the guinea pig, the ancient animal dubbed Josephoartigasia monesi lived in South America about 3 million years ago and with a body mass of about 1000 kg and the size of a buffalo, it is the largest fossil rodent ever to be found.
For their study published in the Journal of Anatomy, Philip Cox, from the University of York, and colleagues used computer modeling and subjected the creature's skull to CT scan to reconstruct a computer model that includes the missing lower jaw copied from a related animal species.
The researchers then tested this model with an engineering technique known as finite element analysis, which predicts stress and strain to know how strong the animal's bite had been and found that its bite was comparable to that of a tiger.
Its front teeth can even withstand forces thrice as larger suggesting that its incisors, which measure 30 centimeters, were not just meant for eating but also for digging and protecting itself from predators.
"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," Cox said. "This is very similar to how a modern day elephant uses its tusks."
Scientists have so far only found one fossilized skull of the South American giant rodent. An almost complete skull, which was unearthed from San José Formation in Uruguay, is preserved in the National History and Anthropology Museum of Uruguay.
The 1,000 kg animal is known to have lived during the Pliocene period, an era marked by an abundance of large animals including the first mammoths. Although its remains were first discovered in 1987, it was not until 2008 that the animal was scientifically described in a study published in the Royal Society's Proceedings B.
To date, it is the largest rodent to be discovered.
"This species with estimated body mass of nearly 1000 kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains," the 2008 study reported.
