Using data for 25,780 species categorized on the International Union for Conservation of Nature (IUCN) Red List, we present an assessment of the status of the world’s vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: on average, 52 species of mammals, birds and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth as much again in the absence of these.

Your News in Brief item 'Cancer forces Tasmanian devil onto endangered list' highlights the plight of this carnivorous marsupial (Sarcophilus harrisii), driven towards extinction by devil facial-tumour disease, which is contagious (Nature 453, 441; 2008). The animal will soon also be uplisted by the 2008 IUCN Red List from its category of Least Concern to Endangered. (Correspondence)