One-fifth of world's vertebrates are threatened, but there is
hope Things aren't looking particularly rosy for the world's
vertebrates: Scientists report that a fifth of them of are at
risk of extinction. But the outlook for those animals -- which
include amphibians, birds, fishes, mammals and reptiles -- would
have been even bleaker without conservation efforts, the
researchers said. The International Union for Conservation of
Nature periodically surveys biodiversity worldwide and
categorizes species on its so-called Red List based on their
extinction risk. A new update compiles data for 25,780
vertebrate species: all mammals, amphibians, birds and
cartilaginous fishes -- such as sharks -- and about 1,500
species each of reptiles and bony fish. Amphibians are the most
at risk, with 30% of species threatened. Of mammals, reptiles
and fish, 21% are threatened, as are 12% of birds. On average,
52 species of mammals, birds and amphibians move one category
closer to extinction each year. But the outlooks improved