Rare giant rat is photographed alive for the first time – 12/06/2023 – Science

For years, the indigenous people of Vangunu, one of the Solomon Islands, insisted that a giant rat capable of gnawing coconuts and threatened with extinction still lived among the forest trees, although its population numbers had declined because of the destruction of its habitat. by loggers.

Previously, no living specimens had been documented. But the inhabitants of Zaira’s village were right.

Researchers from the University of Melbourne and the National University of the Solomon Islands, with help from the local community, recently photographed the Vangunu giant rat (Uromys vika).

It is one of the rarest rodents in the world, and Vangunu is the only island that, as far as we know, has specimens of the species.

The rat, called Vika by the people of Vangunu, is at least twice the size of a common rat, about 45 centimeters, half of which corresponds to the tail, according to the researchers. The observations were published in the journal Ecology and Evolution on the 20th of last month.

Working with the Zaira community was key to finding the rat, said Kevin Sese of the National University of the Solomon Islands — he is from the island of Guadalcanal, southwest of Vangunu Island.

“Knowledge is with the people. They are the guardians of local knowledge,” said Sese, one of the paper’s lead authors. “If it weren’t for them, we wouldn’t know where to put the cameras.”

The researchers changed the type of bait they had been using. They replaced peanut butter — which rotted after being exposed for long periods of time — with sesame oil. A few days after placing the bait, mice began to appear.

Over the course of six months, the paper’s authors captured 95 images of four different mice.

“I was shocked and really surprised because I’ve tried this several times before and only managed to get black mice,” said Tyrone Lavery from the University of Melbourne’s School of Biosciences, lead author of the paper.

This isn’t the first time Lavery has attempted to photograph the mouse.

He and another researcher did intensive searches from 2010 to 2015 using camera traps, aluminum box traps, targeted lighting and active searches in hollow trees, but were unable to find any Vika.

Then, in 2015, Lavery obtained the first DNA sample from a Vika rat that had died after loggers cut down a tree in which it lived. He compared the DNA and skull with other rodents from Australia, New Guinea and the Solomon Islands to show it was a new species.

But this was not enough to prove that the species was still alive.

Zaira has long been campaigning to have her forest area recognized as protected under the Solomon Islands Protected Areas Act 2010, Lavery said. Now that footage shows the Vika are still out there, he hopes it strengthens the village’s case.

The rat’s survival is important for the local ecosystem, where it is part of the food chain, the researcher added. And it has cultural significance for the people of Zaira, whose oral history tells of the mouse and gave ideas of where it might be in the forest and the type of nuts it ate.

But logging has long been a big part of the economy of the Solomon Islands, the 12th largest exporter of raw timber in the world, according to the Economic Complexity Observatory, a data visualization tool for international trade.

Scientists say logging has harmed the islands’ environment.

“I believe the Zaira people are also aware of the effects of logging in other parts of the island,” Sese said. “And I believe that’s one of the things that motivated them to conserve the forest.”