East Timor Was Home to the World's Largest Rat

Posted on July 26, 2010

Timor Rat Skulls


Archaeologists in East Timor have unearthed the bones of the biggest rat that ever lived. The rat bones of 13 spieces - 11 new to science - were found in caves. The largest rat had a a body weight around 6 kg (over 13 pounds). The giant rats jaw was about as large as the skull of common rat. The image above compares the upper toothrows of Timor's enormous extinct giant rat (left), with the skull of a common black rat (right).

Carbon dating shows that the biggest rat that ever lived survived until around 1000 to 2000 years ago, along with most of the other Timorese rodents found during the excavation. Only one of the smaller species found is known to survive on Timor today.

"People have lived on the island of Timor for over 40,000 years and hunted and ate rats throughout this period, yet extinctions did not occur until quite recently," CSIRO's Dr Ken Aplin says. "We think this shows people used to live sustainably on Timor until around 1000 to 2000 years ago. This means extinctions aren't inevitable when people arrive on an island. Large scale clearing of forest for agriculture probably caused the extinctions, and this may have only been possible following the introduction of metal tools."

Timor has very few native mammals. Bats and rodents make up the majority of species. Most of Timor today is arid, transformed from the lush rainforests of the past.

"Although less than 15 per cent of Timor's original forest cover remains, parts of the island are still heavily forested, so who knows what might be out there?" Dr Aplin says.

'Quaternary murid rodents of Timor' by Ken Aplin of CSIRO and Kris Helgen of the Smithsonian Institution was published this week in the Bulletin of the American Museum of Natural History.

The image belows shows the skull of a common black rat compared with one of Timor's extinct giant rats. The rat skull shown here is not even the biggest of the extinct rats, which was about 25% bigger than the skull shown below.

Timor Rat Skulls


Photo: Ken Aplin, CSIRO