The Swiss-based International Union for Conservation of Nature paints a bleak picture of the worldwide status of mammals.The group's most recent assessment, which took 1,700 scientists in 130 countries five years to complete, concludes there is a sharp decline in mammals across the globe.Spokesman Craig Hilton Taylor says urgent action is needed.

"So we have now reassessed all the world's mammals, almost 5,500 species worldwide, and the study shows that almost a quarter of them have either gone extinct or are facing extinction in the near future," Taylor said. "So it is a very worrying situation that we need to do something about quite urgently."

The scientists say large mammals are the most vulnerable and according to the survey nearly 80 percent of primates in South and Southeast Asia face extinction.

The survey shows some parts of Vietnam and Cambodia are facing what scientists are calling "empty forest syndrome," with some monkey populations disappearing from areas where they were once common.The report lists the Australian marsupial known as the Tasmanian Devil and the Asian Caspian seal among the most threatened animals.

Jean-Christophe Vie, an expert with the organization's species program, says many of the problems are man-made.  "No doubt it is habitat destruction," Vie said. "That is the main cause for all groups of species, almost all groups of species. Harvesting, what we call harvesting, which is hunting, poaching, you name it."

The scientists say habitat devastation is a major threat across the tropics, including deforestation in Asia, Africa and the Americas.Hunting is also having a major impact in Asia, Africa and South America.The report says global warming is threatening the polar bear and other Arctic species.Craig Hilton Taylor says these growing problems are getting attention. 

"The world's leaders have got together and through the convention of biological diversity have set the world a target that by 2010 we should reverse and slow down the rate of extinction, the rate of loss of species," Taylor said. "So that is quite an ambitious target to achieve and we are very far from reaching that."

The scientists say among the gloomy news on the survival of earth's living creatures there are glimmers of hope including proof that conservation projects can help some species.Ferrets reintroduced in the western United States and Mexico are making a comeback, as are wild horses, which were reintroduced in Mongolia in the early 1990's.