Prehistoric Giant Rodent May Not Be as Giant

According to Millien's calculation's, J. monesi was "certainly the largest rodent ever described" but weighed in at no more than...770 pounds, or about the same as a medium-sized horse.

By comparison, the biggest rodent alive today is the capybara, which can reach 132 pounds.

Despite its terrifying snappers, the creature -- named after Alvaro Mones, a Uruguayan palaeontologist who specialised in South American rodents -- was a peaceable herbivore that slurped on aquatic plants.

Related Links:

Jennifer Viegas' blog: Born Animal

Introduction to Rodentia

How Stuff Works: Rats