For the Vangunu people of the Solomon Islands, the vika rat isn't a new discovery. They have always shared their forested island home with the giant-tree dwelling rats, which even features in nursery rhymes.

The skull of Uromys vika

Now, Uromys vika has also be described and classified by Western scientists - and immediately put on the list of critically endangered species.

Tyrone Lavery, a biologist with the Field Museum in Chicago, heard locals talk of a giant rat that cracked coconuts open with its teeth, but searched for years without seeing it in the flesh.

"I started to question if it was really a new species or if people were just calling regular black rats 'vika,'" Lavery said.

When a specimen eventually turned up, Lavery quickly realized it could only be the elusive rodent of local legend. "Looking at the features on its skull, I could rule out a bunch of species right away," he said.

"The new species is pretty spectacular," he added. About four times the size of a regular rat, the Field Museum can't confirm that it cracks open coconuts, but it does gnaw holes in them with its teeth.

The remote Solomon Islands archipelago is isolated, and over half the mammals there exist nowhere else on earth.

Nuts gnawed by the vika

"Vika's ancestors probably rafted to the island on vegetation, and once they got there evolved into this wonderfully new species," Lavery said.

Living on just this one island, where its habitat is shrinking due to logging, Lavery said the vika could easily have become extinct without ever being scientifically recorded.

"It's getting to the stage for this rat, that if we hadn't discovered it now, it might never have gotten discovered," he said. "The area where it was found was one of the only places left with forest that hasn't been logged."

The scientist called for support for the Zaira Conservation Area on Vangunu, which is managed by local villagers.