Resembling a guinea pig grown to the size of a buffalo, the animal lived millions of years ago in a South American swamp and is thought to be history's biggest rodent, researchers say this week in the journal Science."

Yet another big thing that didn't survive the last cataclysm, or the one before that... They say it existed millions of years ago, but fossils are such rare things, and judging the timespan of an entire species based on a sample of one is kinda tricky