. Last Updated: 07/27/2016

Report Finds World's Species At Greater Risk of Extinction

WASHINGTON -- Fully one-fourth of the world's species of mammals are threatened with extinction, and about half of those may be gone in as little as a decade, according to the most complete global analysis of endangered animal species ever compiled.

The report, which several conservationists described as surprising and frightening, was released Thursday by the IUCN-World Conservation Union, the recently renamed international body that has collected endangered species data for more than 35 years.

Unlike previous versions of the group's so-called Red List of endangered species, the updated version uses a newly adopted set of objective criteria of endangerment, scientists said. The new system suggests that previous estimates of the number of endangered species worldwide may have been too low.

In a statement released Thursday, Interior Secretary Bruce Babbit called the report "probably the most thorough scientific assessment of the state of the world's wildlife ever undertaken. It clearly indicates that, unless people of all nations make extraordinary efforts, we face a looming natural catastrophe of almost Biblical proportions."

This year's list is the first to evaluate all 4,600 known species of mammals, the class of animal that includes all warmblooded, milk-producing animals. It finds 1,096 at risk. And it concludes that about a third of 275 primate species examined are also at risk, nearly three times the percentage previously believed.

George Rabb, director of Chicago's Brookfield Zoo and a member of the Swiss-based IUCN's species survival commission, which compiled the data from more than 7,000 scientists, government officials and others, said the main factor threatening species survival is fragmentation and degradation of habitats by humans. Pollution is also a major factor, Rabb said.

The international compilation has no direct effect on U.S. listings under the Endangered Species Act. That act recognizes two categories of extinction risk, endangered and threatened, and uses criteria different from the IUCN's.

By contrast, the IUCN recognizes three levels of risk -- critically endangered, endangered and vulnerable -- with precise definitions that depend on surviving numbers of adults, rapidity of decline, and specific habitat pressures. Among other criteria, the categories are assigned to species that have either 80 percent, 50 percent or 20 percent odds of disappearing within 10 years or three generations of the affected animal.

Some Red List highlights:

?A total of 5,205 species now fall within one of the three endangered categories, including 11 percent of bird species, 20 percent of reptiles, 25 percent of amphibians and 34 percent of fish (most of them freshwater).

?44 percent of crocodile species are endangered, an improvement since conservation efforts were initiated in 1971.

?More than 100 species of marine fishes were added this year, including some sharks, tuna, coral reef fish and seahorses.

?The United States currently ranks among the 20 countries with the most endangered species, but that's partly an artifact of the environmental focus here. Madagascar and the Philippines have the highest percentages of their species endangered.