Animals are passing from our lives—literally. Scientists now believe that nearly one in four mammal species faces extinction. Of the 5,478 species of mammals, 1,141 are so endangered that, if unprotected, they will vanish—and with them their unique and amazing genetic configurations evolved over millions of years. Another 836 species are listed as “data deficient,” meaning their status is uncertain.
That news was delivered earlier this month at the World Conservation Congress, in Barcelona, in the form of an international survey assembled over five years by 1,800 researchers in 130 countries. It is the most comprehensive study yet of the status and prospects of the world’s land and ocean mammals.
Among subgroups, the situation is worst for the world’s apes, monkeys and other primates—humans’ closest relations. About half of the remaining primate species face extinction, the result of hunting and deforestation. According to a 2007 report of the International Union for Conservation of Nature, the sponsor of the congress, the surviving members of the 25 most endangered species could fit in a single football stadium.
Overall, the proportion of marine mammals in danger is higher than land animals, with an estimated one-third facing extinction, largely as a result of being struck by ships or drowning after being entangled in fishing nets. Altogether, the IUCN has put 48,838 species (including amphibians and fish) on its species list, of which 16,928 are considered threatened with extinction.
The news isn’t all bad. Endangered animals can be brought back from the brink of extinction, but it requires action. For example, the U.S. Fish and Wildlife Service successfully reintroduced the black-footed ferret, which had been extinct in the wild but bred in captivity, in eight Western states and Mexico between 1991 and 2008.
“The longer we wait, the more expensive it will be to prevent future extinctions,” said Dr. Jane Smart, head of IUCN’s species program. “We now know what species are threatened, what the threats are and where—we have no more excuses to watch from the sidelines.”