Archaeologists have discovered fossils from seven ancient rat species on East Timor, including fossils belonging to the largest rats ever discovered. The real-life rodents of unusual size coexisted with humans on the island until about a thousand years ago, and weighed up to 11 pounds—which, to be clear, is about twice the weight of a Chihuahua.

"They are what you would call mega-fauna. The biggest one is about five kilos, the size of a small dog," Dr. Louys of the Australian National University explained. According to Science Daily, the largest of the fossils belonged to rodents about 10 times bigger than modern rats.

Archaeologists discovered the fossils while working on the "From Sunda to Sahul" project, which is attempting to trace the migration of early humans through Southeast Asia. They found evidence of human life on the island dating back around 46,000 years, which means that the people of East Timor were dealing with an enormous rat infestation for thousands of years. But it also seems like the people on the island made the best out of their rodent situation. According to Dr. Louys, some of the rat bones have cut and burn marks, which implies they were used as a food source by the island’s early inhabitants.

Scientists are still trying to figure out why the giant rats went extinct: "The funny thing is that they are co-existing up until about a thousand years ago,” Louys explained. “The reason we think they became extinct is because that was when metal tools started to be introduced in Timor, people could start to clear forests at a much larger scale.”

[h/t: Science Daily]