Cat-sized rat discovered in South Pacific

If you have a tendency to jump shrieking on to a table when you see a mouse, look away now: a species of rat the size of a cat has been discovered.

The outsized rodent, which has been named the Bosavi woolly rat, is almost a metre long and weighs in at 1.5kg. It was found trapped inside the crater of Mt Bosavi, an extinct volcano on Papua New Guinea, which has been described as a "lost world" in which scientists have found some 40 previously undiscovered species.

The rat has dense silvery grey fur and the shape of its teeth suggests it is primarily a vegetarian. It is thought to live in subterranean nests.

The animal was found by a BBC Natural History Unit film crew and Dr Kristofer Helgen, of the Smithsonian Institute in Washington DC.

"This is one of the world's largest rats," he said. "It is a true rat, related to the same kind you find in the city sewers, but a heck of a lot bigger."

Despite the BBC's claims, there have been previous reports of the species existence.

In 2007 Kristofer Helgen, a scientist with the Smithsonian Institution in Washington, reported the rat was "about five times the size of a typical city rat".

Dr George McGavin, the head scientist of the BBC Natural History Unit, however, suggested the rodent was not aggressive.

"This rat was incredibly tame," he told the Guardian newspaper. "It just sat next to me nibbling on a piece of leaf. It won't have seen a human before."

Some of the other new species found include a fanged frog, a fish that grunts and a gecko. The fish has been called the henamo grunter because of the noises it makes with its swim bladder.

The Bosavi silky cuscus, a marsupial that lives up trees and feeds on fruits and leaves, was another creature not to feel threatened by the human visitors, climbing on to the shoulder of Steve Backshall, a climber and naturalist.

"I can't begin to describe how it feels to have an animal in my hands that in all probability has never before been seen by science," he told the Guardian. "Most biologists would consider it a great achievement to name one new species but at some points on this trip it seemed like everything we were looking at was new. The end of every day was like a massive party. It was very special."

Taken there by local trackers, the group stayed in the crater for two weeks in January to film a BBC series on Mt Bosavi called Lost Land of the Volcano.

The area was so remote the expedition team had to organise for fields of sweet potato and spinach to be planted in the jungle six months in advance so they would have a ready food source.

Weeks were also devoted to negotiations - which had to be translated into the local language, Kasua, spoken by fewer than 1000 people - to gain permission to cross land owned by local clans.

- INDEPENDENT