8 million years ago, an evolutionary cousin of the guinea pig (phoberomys pattersoni) was the size of a cow and is the largest rodent to ever roam the world.

Interesting History Fact: 

Did you know? 8 million years ago, an evolutionary cousin of the guinea pig (phoberomys pattersoni) was the size of a cow and is the largest rodent to ever roam the world. 

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