The Terrifying Guinea Pigs Of Ancient History

By Morris M. on Wednesday, October 16, 2013
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“What’ve they got in there, King Kong?” —Dr. Ian Malcolm, Jurassic Park (1993)

In A Nutshell

You’d be hard-pressed to come up with an animal less terrifying than a guinea pig. Short, unintelligent, and utterly harmless, today’s guinea pigs are the epitome of both cuteness and stupidity. However, their evolutionary ancestors were another thing altogether: Eight million years ago, South America was swarming with guinea pigs the size of buffalo.

The Whole Bushel

In 2003, scientists made a bizarre discovery in Venezuela. In the mud outside a small, anonymous town, an eight-million-year-old guinea pig skeleton had been incredibly preserved. But what was truly shocking about this rodent was its size: “Guinea-zilla” would have been 1 meter (3.5 ft) tall, nearly 3 meters (10 ft) long and weighed an astonishing 700 kilograms (1,500 lbs).

Although a vegetarian, everything about this creature would have been terrifying. Its teeth were nearly 20 centimeters (8 in) long, with evidence to suggest they simply never stopped growing. They moved about in packs and could exist happily either on land or in water. Their upper body strength was likely tremendous. In short, this would have been one guinea pig you didn’t want to pick a fight with.

It should be noted, however, that this was a period of time when everything was huge. Turtles regularly topped out at 3 meters. Raccoons were the size of bears. A bird known aptly as the “terror bird” was so big it ate freaking horses. But still: Guinea-zilla has been proven to be a direct evolutionary ancestor of our modern guinea pig. What might have caused the largest rodent in history to shrink down to one-seven-thousandth of its original size is a question we might never know the answer to. Still, we can be thankful it did, or else our childhoods may well have been very different.

Show Me The Proof

BBC: Giant rodent astonishes science
Prehistoric guinea pig was largest rodent on Earth
NatGeo: ‘Guinea-zilla’—World’s Largest Rodent?