Rodents of unusual size? Researchers find giant, tree-dwelling rat in Solomon Islands

Deep in the forests of Vangunu in the Solomon Islands lives a rat like no other you've likely ever seen. It's more than four times the size of an average rat and weighs more than a kilogram.

Meet Uromys vika, a new giant rat species.

The Solomon Islands in the South Pacific are home to some unique species, a result of the relative isolation of the islands. In particular, they are home to a number of giant rats species.

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In 2010 while on a visit to the island of Vangunu, mammalogist Tyrone Lavery heard stories of a giant, coconut-cracking rat from locals. He was convinced that this was a new kind of rat because while several giant rat species had been found in parts of the Solomon Islands, none had yet been discovered in the region known as the Western Province, which includes Vangunu and several other islands.

"Those islands have also never been connected to the other Solomon islands, so I knew that if something had managed to arrive in the Western Province, it was a really good chance it would be a new species," said Lavery, lead author of the findings, which were published in the Journal of Mammalogy Wednesday.

A shrinking habitat

You'd think finding a giant rat would be easy, but Lavery spent five years searching for the elusive rodent.

While spending time on a tropical island may sound like paradise, Lavery said that it was a gruelling experience: long hikes through the forest, plenty of long rainy days setting up traps and cameras, and digging through layers of vegetation to try to find some clue as to the rat's existence.

And then by accident he and his colleague Hikuna Judge found vika.

It's important to document these animals to know they're there and conserve them.- Tyrone Lavery, mammalogist

The rat was discovered near the village of Zaira during a hike in 2015. 

Lavery and his colleague spotted the rat scurrying out from a tree that had been logged near the community trying to protect its rich forest from logging companies active throughout the islands where various species of these giant rats live.

The researchers captured the injured rat, which later died. 

"Logging is quite a threat to a number of [mammal] species," Lavery said.

That's because many species — including many bats that Lavery studies in the islands — rely on old trees, those with hollows in them where the mammals can live.

"And logging removes most of those trees," he said. 

The researchers compared the dead rat's skull to existing giant rat skulls from other museums and collections. They found that this rat was like no other ever documented. The new species, Uromys vika, became the first rat discovered in the Solomon Islands in 80 years. 

"It's important to document these animals to know they're there and conserve them," Lavery said. 

There are other giant rats living in the forests across the Solomon Islands. To date there have been eight species identified. 

And while this vika rat may seem like a nightmare to some, Lavery looks at it quite fondly.

"People … not having seen this rodent, [believe] it's scary to think of a rodent that large," he said. "I don't think of it as scary. I think they're quite unique animals. And I think this rat is quite cute for a rat."