Published online 6 October 2008 | Nature | doi:10.1038/455717a


A quarter of mammals face extinction

Latest Red List finds 80% of southeast Asian primates are at risk.

Iberian lynxIberian lynx are threatened with extinction.Spanish Environment Ministry/Reuters

One in four of the world's mammal species is threatened with extinction, according to the first comprehensive survey of this class of animal. Populations are declining in half of all mammal species, with some experiencing an extreme decline; Tasmanian devil (Sarcophilus harrisii) numbers plummeted by 60% over the past decade, for example.

The survey placed 188 species in the most severe, 'critically endangered' category, including the Iberian lynx (Lynx pardinus), which has a wild population estimated at 84–143 adults. Precise data were unavailable for some species, but the researchers estimate that the proportion of mammal species threatened with extinction is between 21% and 36%.

The mammal survey (J. Schipper et al. Science doi:10.1126/science.1165115; 2008) is part of a global review of threatened species by the International Union for Conservation of Nature (IUCN). The IUCN produces a yearly Red List ( of species at risk, and a global assessment of the health of the world's species every four years. These are used by governments and wildlife organizations to decide conservation-management strategies and funding allocation.

In 52% of the mammal species for which population trends are known, numbers are dwindling, and they will continue to fall unless conservation schemes are put in place, according to the survey led by Jan Schipper of the IUCN's mammal assessment programme, based in Washington DC. The greatest threats that mammals face are deforestation, habitat loss and hunting. And the most dramatic population declines are occurring in southeast Asia, where around 79% of primates are threatened with extinction, the survey found.

Mammal numbers will continue to drop as new threats, such as pollution, arise, says Schipper. "The results paint a very bleak picture of mammals worldwide. More species are declining than expected and threats are increasing," he says.

The survey covers all 5,487 mammal species, including marine mammals, which have not previously been assessed for the Red List. The last global mammal assessment was carried out in 1996, but much of the information is out of date and nearly 700 recognized species were not included, making meaningful comparisons over time impossible. "This latest survey is now a baseline of conservation status. The next step is to monitor trends," Schipper says.

The researchers collected detailed information, including distribution, habitats, population trends and threats, all of which will be publicly available. "There have been questions before over how the Red List was drawn up. But now you can go in and see the data and look at why decisions on status have been made. It is much more transparent," Schipper says.

This year's Red List also covers a far broader range of animals (see 'Vanishing creatures'), including many invertebrates for the first time — previously, lack of resources limited the list to better-known bird and mammal species that make up only 2–3% of the world's biodiversity.


"We are now emerging from the dark ages of conservation knowledge, when we relied on data from a highly restricted subset of species," says Jonathan Baillie, director of conservation programmes at the Zoological Society of London. "We will expand the scope further to include a far broader range of groups, thus informing and assisting policy-makers in a hugely more objective and representative manner." 

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