The is the largest rodent in the world. The ’s name comes from the native people of South America. It means "master of the grass." The scientific name of the is hydrochoerus hydrochaeris, which means "water pig" in Greek. s have been in existence since the Pleistocene epoch. Their ancient ancestors were rodents that lived about sixty million years ago. The average size of a is four feet in length and two feet in height. This is about the size of a sheep. s usually weigh between sixty and one hundred and forty pounds. Many people ....