Giant pacarana was the largest rodent ever. It lived during the Pliocene Epoch, a time in Earth’s history from about 5.3 million to 2.6 million years ago.
The giant pacarana had a large head, small ears, a thick neck, and a long tail. By some estimates, the giant pacarana weighed as much as a modern cow or bison, at more than 2,200 pounds (1,000 kilograms). Other estimates put the weight at around 775 pounds (350 kilograms). Even at the lower weight, the giant pacarana would have been nearly 10 times as heavy as the largest living rodent, the capybara of South America. The giant pacarana was about 5 feet (1.5 meters) tall and 10 feet (3 meters) long.
The giant pacarana lived in the dense forests of tropical South America. It probably ate plants, foraging (searching) for food along riverbanks. It may have been slow-moving and secretive, feeding mainly at night. Its enormous jaws and teeth provided tremendous bite force. Its incisors (front teeth) were likely used for crushing tough, fibrous plants; digging for food; and defending against predators. Jaguars and other forest-dwelling cats were the giant pacarana’s main predators. The rodent’s size and huge teeth probably discouraged all but the boldest predators from attack.
The giant pacarana takes its name from a living relative, the pacarana. The pacarana lives in the Amazon Basin of South America. Pacarana means false paca in the language of the Tupi-Guarani people of the Amazon rain forest. The name distinguishes the pacarana from another local rodent, the paca. The pacarana is the third largest living rodent, behind the capybara and the beaver. The paca, pacarana, and giant pacarana are all relatives of the guinea pig.
About 3 million years ago, the Panama land bridge formed, connecting North America and South America. The giant pacarana likely went extinct as North American species crossed the land bridge into South America. This invasion brought such predators as large cats and bears into the giant pacarana’s range. Climate change may have also contributed to the extinction of the giant pacarana.
Scientific Classification: The pacarana and the giant pacarana belong to the family Dynomyidae. The scientific name of the giant pacarana is Josephoartigasia monesi.
