Tuesday, July 10, 2007

The Great-Granddaddy of Guinea Pigs

WOW! What an ancestor this was!

In the deserts of northwestern Venezuela, paleontologists have uncovered the fossil remains of a rodent as large as a cow. Weighing more than three-quarters of a ton (1,545pounds) and standing 4.2 feet tall, the animal Phoberomys pattersoni lived about 8 million years ago during the Miocene epoch, which lasted from 23.8 to 5.3 million years ago. Nicknamed "Goya," the individual specimen is the largest rodent ever discovered--more than 13 times as large as the largest living rodent, the capybara. Capybaras weigh around 110 pounds.

Today's guinea pig

Today's guinea pig (Photo)
Teeth and other bits of the genus Phoberomys have been found before, but Goya is 90 percent complete. The research team was led by a scientist from Venezuela's Universidad Nacional Experimental Francisco de Miranda. The National Geographic Society and the Smithsonian Tropical Research Institute also supported the mission.

Teeth That Grey--and Grow

Goya was found in the Venezuelan town of Urumaco in a layer of earth called the Urumaco Formation. Scientists believe that during the Late Miocene, a river called the Paleo-Orinocok, Amazon flowed parallel to the Andes Mountains through Urumaco and into the Caribbean Sea. Remains of both animals and plants found in association with Goya suggest the now-arid landscape was once a lush place of rivers and wetlands. Like the capybara, Phoberomys was probably semi-aquatic, wading and foraging in the marshes alongside rivers.

Comparison of Goya with another, less-complete specimen led scientists to classify Phoberomys pattersoni as being related to a species of South American rodent called the pakaranas. The latter is a close relative of the guinea pig. In fact, Goya looked very much like a guinea pig--except it was nine feet in length and had a long tail.

Like guinea pigs and all other rodents, the front incisors of Phoberomys grew continuously and had to be worn down through gnawing. This suggests Goya ate abrasive foods such as coarse grasses growing along riverbanks and in marshes.

Modern guinea pigs, like Goya, also have their origins in the Miocene, when the Caviidae family of rodents appeared about 20 million years ago.

Cavies--as guinea pigs are sometimes known, after their scientific name Cavia porcellus--are native to the grasslands of South America. They can also be found high in the Andes Mountains.

A Queen's Pet

The Inca domesticated guinea pigs around 5000 B.C., using them for food. Even today guinea pigs are eaten in Andean households, where they are commonly kept and raised in the kitchen. They are valued for the high-protein content of their meat.

How guinea pigs received their name is a mystery--they are rodents, not pigs. One theory holds that their meat tasted like pork to European conquistadors and traders. The "guinea" part of the name may stem from "Guyana," an area in South America from which traders sailed. It could also be a reference to the cost of the animal: one guinea, an old kind of British coin.

Regardless, the furry little creatures were big hits once traders brought them back to Europe. Even England's Queen Elizabeth I had one as a pet!

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