Fall in Love With This Newly Discovered Giant Island Rat

The Vangunu rat is the first rodent species to come to light on the Solomon Islands in 80 years—and it’s already endangered

U. vika illustration, copyright Velizar Simeonovski, The Field Museum (1).jpg
The elusive Vangunu giant rat lives in trees, a habitat under attack from deforestation in the Solomon Islands. Illustration by Velizar Simeonovski/The Field Museum

When mammalogist Tyrone Lavery traveled to the island of Vangunu in 2010 to research the region’s mammals, the last thing he expected was that he’d be embarking on a seven-year search for an undiscovered species.

Vanganu, a 210-square-mile island belonging to the Solomon Islands chain in the South Pacific, was only accessible by boat; Lavery’s group were among the first outsiders ever to visit the village of Zaira. But despite being unfamiliar with outsiders, the villagers were more than hospitable—they pointed Lavery in the direction of several critters, including a fluffy brown rat he’d never heard of.

“They told me about this giant rat they called ‘vika’—a big rat that lived in the canopy,” Lavery says. From there, it only took seven years of climbing trees, getting soaked in rain showers and peering through dense vegetation to find the rat. And it was indeed large: 18 inches long from nose to end of the tail, or about the size of a small opossum.

Next, Lavery did morphological and genetic analyses to compare the rat to other related species, then had his research vetted by other scientists. Now, he is the author on a new study announcing the first rodent species discovered on the archipelago in the past 80 years—all thanks to the advice he got on his first visit. Today the species Uromys vika makes its world debut in the Journal of Mammalogy

This remarkable rodent is only the latest in a string of new animal discoveries, including the rose-tinted katydid, the slender rat and the purple pig-nose frog. “People talk about how the age of discovery isn’t over and there’s some truth to that,” says Eric Sargis, curator of mammals at the Yale Peabody Museum. “With the combination of doing surveys, continuing field work, and also reassessing the amazing collections available in museums, people are going to keep discovering new species.”

The partnership that made Lavery’s discovery possible is largely thanks to the Zaira villagers’ dedication to conservation. In the past three decades, the logging industry has exploded across the Solomon Islands; about 60 percent of the small nation’s GDP comes from cutting down trees, according to a United Nations documentary. Since communities are the landowners, they have the power to resist—but often need money for school fees and to improve their village.

In Zaira, though, people have preserved their forests and are working towards building an industry around ecotourism. According to Lavery, only about 30 square miles of lowland rainforest remain on Vangunu, and that is largely in Zaira. “This rat was found right on the edge of their land,” Lavery says.

So much for the good news. The bad news is that, despite only being announced to the world today, the Vangunu giant rat is already critically endangered. On the plus side, Lavery hopes that awareness of the rat’s existence and endangered status could help keep its valuable surroundings protected. “Recognition of this rare mammal will increase recognition of the value of the area,” he says.

Although Lavery doesn’t have a definite estimate for how many of the rats there might be, they’re only known to exist on Vangunu and they require the rainforest habitat to survive, of which there’s only a small portion left. “They have giant white-tailed rats in Australia that are similar to this species,” Lavery says. Those continental rats are sparse in their habitats—only two to seven of them per hectare [10,000 square meters]—and he estimates even fewer giant rats live in the same space on Vangunu.

Because it has been such a challenge to even prove the existence of the Vangunu rat, little is known about its behavior. Researchers found nuts with holes gnawed through them, and Lavery speculates that the rats might sit in trees eating fruit and dispersing seeds to the forest floor. They’ll need more data before they can be sure, but it’s possible the rat plays an important role in the ecosystem.

Fall in Love With This Newly Discovered Giant Island Rat
Nuts chewed by the Vangunu giant rat, recently discovered in the Solomon Islands. The rat is also thought to crack open coconuts with its prodigious teeth. Courtesy Tyrone Lavery, The Field Museum

“On more isolated big islands, rats are a huge proportion for the total mammal diversity, so they’re filling all kinds of roles,” says Jacob Esselstyn, curator of mammals at the Museum of Natural Science at Louisiana State University. “There are rats that feed on seeds, rats that feed on fruits, rats that feed on earthworms, rats that feed on leaves. In continental situations [these niches] would be filled by other mammals like monkeys and hedgehogs.”

Like Lavery, Esselstyn has discovered new rodents, including the Sulawesi water rat and the “super shrew,” which boasts a remarkably strong interlocking spine. Sometimes those discoveries have even come about thanks to the assistance of indigenous people. After his first such discovery, “I’ve listened a lot more carefully to what villagers have to say,” Esselstyn says.

But whether people will care enough about these new species to protect them from extinction is another question. Despite all they do for their ecosystems, rats can come with a certain ick-factor for city dwellers accustomed to thinking of them as red-eyed sewer pests.

“Almost 26 percent of muroid species [rats, mice, gerbils and others] are on the IUCN Red List of Threatened Species,” reports the University of Michigan Museum of Zoology. But “few steps have been taken to save threatened muroid species; they are not particularly charismatic or popular with the public and in many cases there is simply not enough known about them to know where to begin.”

Or as Esselstyn says: “Rats are never going to be the center of any flagship conservation program.”

But that doesn’t mean they won’t ever get protection.

Vangunu is also home to monkey-faced bats, and welcomes leatherback turtles to its beaches, where the turtles lay their eggs. If even one of those species can gain the world’s attention, it might mean umbrella protection of the habitat for the others. As Sargis says, “If you can get some conservation excitement, the downstream effects if that environment is conserved are going to affect many other species that people don’t put on posters.”

Lavery himself remains optimistic. They’re setting up cameras in new areas to find more of the rats and he plans to continue his work on Vangunu. “It’s a very special place to me, one of my favorite places in the Solomons,” Lavery says. “They’re quite inspiring for the vision they have for not resorting to logging.”

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