Solomon Islands locals have long spoken about giant rats that scurry around in trees and crack open coconuts, but it was never clear whether such a species actually existed. Now, scientists have found the creatures and confirmed that they are in fact a brand new species.

The new species, dubbed Uromys vika, can weigh up to 1 kg (2.2 lb) and measures about 45.7 cm (1.5 ft) from its nose to the tip of its tail – for reference, an typical adult male brown rat weighs on average 350 g (12 oz), while a typical adult male black rat weighs between 75 and 230 g (2.6 to 8 oz).

The discovery was made by Tyrone Lavery, a mammalogist and researcher at the Field Museum in Chicago, along with fellow scientists John Vendi and Hikuna Judge. During a trip to the Solomon Islands in 2010, Lavery heard stories of the giant tree-dwelling rodents, which the locals called vika. Unfortunately, that choice of habitat made the creatures particularly difficult to track down.

"I started to question if it really was a separate species, or if people were just calling regular black rats 'vika'," says Lavery. "If you're looking for something that lives on the ground, you're only looking in two dimensions, left to right and forward and backward. If you're looking for something that can live in 30-foot-tall trees, then there's a whole new dimension that you need to search."

Eventually though, the team's persistence paid off. A specimen was found in a fallen tree, and Lavery was able to tell on sight that it didn't belong to at least some known species. DNA analysis soon confirmed it to be completely new to science, and the team called it Uromys vika in honor of its traditional local name.

"There are only eight known species of native rat from the Solomon Islands, and looking at the features on its skull, I could rule out a bunch of species right away," says Lavery. "This project really shows the importance of collaborations with local people."

Unfortunately, the difficult search might have been indicative of another problem: the rare rats seem to be under threat by deforestation, and it looks like the new species will be fast-tracked to the Critically Endangered list.

"It's getting to the stage for this rat that, if we hadn't discovered it now, it might never have gotten discovered," says Lavery. "The area where it was found is one of the only places left with forest that hasn't been logged. It's really urgent for us to be able to document this rat and find additional support for the Zaira Conservation Area on Vangunu where the rat lives."

A research paper describing the new species was published in the Journal of Mammalogy.

Source: Field Museum

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