Large treedwelling rat found in Solomon Islands
WASHINGTON: People living in the Solomon Islands long had spoken of a big, treedwelling rat called vika that inhabited the rainforest, but the remarkable rodent managed to elude scientists — until now.
After searching for it for years with cameras mounted in trees and traps, scientists said they finally caught up with the rat on Vangunu Island, part of the Solomons, spotting one as it emerged from a tree felled by loggers.
It instantly joined the list of the world’s biggest rats, weighing about four times more than an ordinary rat and measuring about half a metre long.
‘‘Vika lives in a very thick, complex forest, and it is up in the canopy so it is difficult to find. It is also a rare species. It is likely there are not many of these rats left,’’ mammalogist Tyrone Lavery of the Field Museum in Chicago, who led the research, said yesterday.
The orangebrown rat eats nuts and fruit. It has short ears, a smooth tail with very fine scales and wide feet that allow it to move through the forest canopy.
The rat is reputed to chew holes in coconuts to eat the inside. ‘‘I haven’t found proof of this yet, but I have found that they can eat a very thickshelled nut called a ngali nut,’’ Lavery said.
A small number of rat species around the world rival vika’s size. Lavery said a vika relative also inhabiting the Solo mon Islands, called Poncelet’s giant rat, was twice the size.
The world’s largest rodent is not a rat, but South America’s barrelshaped capybara.
A phenomenon called the ‘‘island effect’’ may help account for the size of vika and other big rat species in the Solomon Islands.
‘‘The island effect, or island syndrome, relates to the effects living on an island has on the evolution of body size. On islands, small species such as rats, evolve to have larger body size, they attain higher population densities and they produce fewer offspring,’’ Lavery said.
‘‘Vika also probably arrived on an island where there were no other large mammals living in the canopy eating fruits and nuts so the species evolved to fill this niche.’’
Vika should be considered critically endangered, with logging threatening its habitat, Lavery said .
The research was published this week in the Journal of Mammalogy. — Reuters
PHOTO: REUTERS