Every single species and subspecies of great ape on the planet now teeters on the edge of dying out, part of the acceleration of the dinosaur-style mass extinction now under way.

In all, 11,167 species of plants and animals are at risk of extinction, according to the 2002 version of the IUCN Red List of Threatened Species, which is to be released today in Switzerland. It is the world's most authoritative catalogue of those on the brink of vanishing from the planet's genetic pool.

The number, an increase of 121 species just since the last count in 2000, provides clearer evidence than ever before that the Earth's life forms are set on a course toward the sixth mass extinction in the planet's history, on a par with the one 65 million years ago that extinguished the dinosaurs.

"This is further affirmation of a very significant and dangerous trend," said Achim Steiner, director-general of the Swiss-based IUCN (World Conservation Union).

Scientists believe that the current rate of extinction is between 1,000 and 10,000 times the rate biologists would expect under normal conditions. Extinction is normal in biological systems, but very rare, often as low as one or two species a decade. The overwhelming reason species are dying out so fast is that humans are making their living spaces uninhabitable or are killing them outright.

The case of primates is among the most dire, says a companion report, Primates in Peril, released yesterday in Washington by Conservation International and the IUCN's Species Survival Commission.

The report gives details and rare pictures of the 25 most endangered primates, which include the greater bamboo lemur, the Perrier's sifaka and the silky sifaka, all of Madagascar.

Just two years ago, when the most recent survey of primates was completed, 120 of the world's 638 species of lemurs, monkeys, apes and other primates were at great risk of dying out.

Today, that figure is 195, the result of more research on primates coming from Asia.

It means that roughly a third of primates could go extinct over coming decades or even sooner. Not only are humans destroying the jungles and other landscapes primates need, but they are also hunting them for a growing commercial bushmeat market, the report said.

Russ Mittermeier, a primatologist who is president of Conservation International and head of the IUCN's Primate Species Survival Commission, said the great push right now is to raise enough money to keep the primates alive.

He said conservation scientists understand how to save species and have already chalked up successes in Brazil in bringing monkeys back from the brink.

He said it would take between $10-million (U.S.) and $20-million every year for five years to keep most of the primate species alive for the next century.

"If they go extinct, our world will be a poorer place," he said yesterday. "I'd feel very embarrassed having to tell my kids that we let these animals go."

Some of the most endangered primates are down to a handful of individuals in the wild.

They include Miss Waldron's red colobus monkey, which was thought to be extinct until a fresh skin was found earlier this year in a hunter's collection in southeastern Ivory Coast.

Also grave is the situation of the 13 species and subspecies of great apes: chimpanzees, gorillas and orangutans.

Apes are genetically the most similar to humans, making up -- with humans -- the taxonomic family Hominidae. The new findings mean that humans are the only species in the family that are not endangered.

Primates have been vaulted into danger of extinction only in the past three decades as their tropical forest homes have fallen to loggers, Dr. Mittermeier said. Before that, they were plentiful.

The IUCN's Mr. Steiner said he is optimistic that humans, the cause of the problem, can also come up with a solution. He said one of the keys is for conservationists to interact with those in the development field, rather than opposing them.

Species at risk

According to the Swiss-based IUCN (World Conservations Union), 11,167 species of plants and animals are now at risk of vanishing from the planet. Today, the IUCN publishes its Red List of Threatened Species, a catalogue of those species on the brink of extinction.

Here is a list of the top 25 most endangered primates and where they are found.

Number of endangered species of lemurs,
monkeys, apes and other primates in 2000.

Endangered species                         120


Primates not at the point of extinction    518

Number of endangered species of lemurs,
monkeys, apes and other primates in 2002.

Endangered species                         195


Primates not at the point of extinction    443


The top most endangered primates, and the regions where they are found.

Name of species............................Region

Greater bamboo lemur                       Madagascar


Perrier's sifaka                           Madagascar


Silky sifaka                               Madagascar


Black-faced lion tamarin                   Brazil


Buff-headed capuchin                       Brazil


Northern murtqui                           Brazil


Miss Waldron's red colobus                 Ghana and Ivory Coast


Roloway guenon                             Ghana and Ivory Coast


Tana River mangabey                        Kenya


Sanje mangabey                             Tanzania


Natuna banded leaf monkey                  Indonesia


Pig-tailed snub-nosed monkey or Simakobu   Indonesia


Delacour's langur                          Vietnam


Golden-headed langur                       Vietnam


White-headed langur                        China


Gray-shanked douc                          Vietnam


Tonkin snub-nosed monkey                   Vietnam


Yunnan snub-nosed monkey                   China


Guizhou snub-nosed monkey                  China


Eastern black crested gibbon               China and Vietnam


Mountain gorilla                           Congo, Rwanda, Uganda


Cross river gorilla                        Nigeria and Cameroon


Sumatran orangutan                         Indonesia