Nepal is appealing to international donors to help it finally settle a long-running dispute over the height of Mount Everest, a government official said Wednesday.

The world's highest peak, which straddles Nepal and China, is usually attributed a height of 8,848 meters (29,029 feet) following an Indian survey in 1954, but other more recent measurements have varied by several meters.

Bottlenose dolphins have whistles which they use to exclusively greet other members of their species, marine biologists in Scotland reported on Wednesday.

Using hydrophones, the researchers made recordings of dolphins swimming in St. Andrews Bay, off the northeastern coast of Scotland, in the summers of 2003 and 2004.

Scientists say they have proof that the Tyrannosaurus rex, the dinosaur adored by children and makers of plastic toys, had the most powerful bite of any creature that lived on land.

The bite of a grown T. rex was up to 10 times that of a Mississippi alligator, exerting a force of nearly six tons -- the weight of an elephant -- on a single tooth, according to a study published on Wednesday.

After two unexpected pregnancies at a sanctuary for retired research chimpanzees, other females have been put on birth control and the males are getting another round of vasectomies.

The first recent pregnancy at the Chimp Haven Inc. facility near Shreveport in northwest Louisiana was discovered on Valentine's Day when a worker noticed Flora, a 29-year-old chimp, was carrying a newborn.

Melting sea ice in the Arctic may be causing the snowier winters the northern hemisphere has experienced in the last two seasons, U.S. and Chinese researchers have reported.

The level of Arctic sea ice reached a new record low in 2007, said the study led by the Georgia Institute of Technology and published in the Proceedings of the National Academy of Sciences on Monday.

A coalition of environment groups called Tuesday for the world's largest marine reserve to be declared in Antarctica's Ross Sea to prevent "industrial scale" fishing ruining the pristine ecosystem.

The Antarctic Ocean Alliance said waters surrounding the remote frozen continent were facing increased exploitation as fish stocks elsewhere in the world continue to decline.

Fossilized remains of one of the largest penguins ever, an "elegant" giant standing 1.3 meters (52 inches) tall, have been found in New Zealand, scientists said Tuesday.

The penguin lived 27-24 million years ago, when New Zealand was mostly underwater and consisted of isolated, rocky outcrops that offered protection from predators and plentiful food supplies, researchers said.

Poles have turned to cyberspace to circumvent a new animal rights law in Poland forbidding the sale of dogs and cats without a breeding license, which had been intended to stamp out cruelty to animals.

The law, which came into force on January 1, was intended to tackle the appalling conditions in which some unlicensed breeders kept their animals.

The destruction of Brazil's Antarctic base in a fire that killed two navy personnel has dealt a major blow to the country's strategic research on the resource-rich continent, experts say.

"All the central core of the base, where the installations were concentrated, was lost. The exact extent of what occurred still needs to be determined, but the assessment is that we really lost virtually everything," Defense Minister Celso Amorim said late Saturday.

For the past two decades, the U.S. space agency has been practically obsessed with Mars. It has hardly missed an opportunity about every two years to fling robotic spacecraft at the red planet.

This summer, the most high-tech rover ever, Curiosity, will land near the Martian equator in search of the chemical building blocks of life. The more scientists study Mars, the closer they get to answering whether microbial life once existed there, a clue to the ultimate question: Are we alone?