One Ton Rat?

This skull is virtually identical to that of a mouse, rat, muskrat, groundhog, or beaver. The story, below is from CNN:

Scientists have discovered the remains of a rodent the size of a small car which used to forage the South American continent. The 1-ton creature is believed to have been about 3 meters in length and 1.5 meters tall.

The giant rat's skull, which measures an impressive 53 centimeters in diameter was found by Andrés Rinderknecht and Ernesto Blanco, two scientists from Montevideo, Uruguay.

The two paleontologists stumbled upon the fossilized remains in a broken boulder in San Jose along the coast of Uruguay.

By looking at the size ratios of the skulls and bodies of existing rodents, scientists determined the bodyweight of the rodent must have approached 1,000 kilograms or a ton, making it the world's largest rodent to have been discovered to date.

The relatively small size of its teeth however, suggests it fed mainly upon soft vegetables and fruit.

"We can give an educated guess that the rodent would have been 3 meters long -- assuming that it was similar to a Capybara (the largest rodent alive today) and taking it into account that large mammals generally have relatively smaller heads. It's tail probably was closer to the one of capybara or guinea pig (very short) and not like a rat," Ernesto Blanco says.

The scientists believe the rodent, named Josephoartigasia monesi, roamed the earth about four million years ago at the same time as other giant creatures, such as terror birds, saber-toothed cats, ground sloths and giant armored mammals.

During this period, the now arid region was forested and rich in vegetation. The largest living rodent is the capybara, a 50 kilogram guinea pig found in South America.
.