2000-year-old giant rat was forty times bigger than its modern relatives

Eleven species of rodent that are entirely new to science were discovered in a cave in East Timor, but one species quite literally dwarfs all the rest - the biggest rat ever discovered, even larger than most modern house cats.

The giant rat would have weighed as much as 13.2 pounds when fully grown. If that doesn't sound like much, keep in mind most rats max out at about 5 ounces, and the heaviest rats alive today are still less than a third the size of this monster. To get a sense of scale, the image up top compares just the upper teeth of the giant rat with the entire skull of the common black rat.

The cave is home to some generally impressive rats - eight of the fourteen species found in the cave weighed more than 2 pounds. East Timor, which shares with Indonesia the Southeast Asian island of Timor, is part of a larger region known for its extensive rat evolution. East Indonesia in general gave rise to some of the biggest and most fearsome rats in recorded history, with similar bonanzas of new species discovered in several other caves throughout the islands.

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In explaining why the giant rats went extinct somewhere between 1000 and 2000 years ago, study leader Ken Aplin explained:

"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. Large-scale clearing of forest for agriculture probably caused the extinctions, and this may have only been possible following the introduction of metal tools."

The majority of East Timor is now arid, with much of its original rainforest long gone. Still, that 15% of rainforest that remains is some of the most densely covered, least explored regions in the entire world, and Aplin doesn't rule out the possibility that some live specimens of unusually large rats might well be out there.

Of course, all of this is just more proof that Doctor Who is scarily prophetic. Be sure to bring your best Birmingham-made firearm if you go looking for rats in East Timor:

[Bulletin of the American Museum of Natural History]