There are nearly two million known species on the planet. But
many of those won't be around much longer; one out of every
eight known bird species, one in four mammal species, and one in
three amphibian species are at risk for extinction, according to
the World Conservation Union (IUCN), which maintains the Red
List, a catalog of the world's species classified according to
their risk of extinction. "It's supposed to inform conservation
practice, to be a wake-up call for the extinctions that are
happening," says Caroline Pollock, a program officer with the
Red List unit. Animals that are classified as "critically
endangered" are at the highest risk--their numbers in the wild
may be extraordinarily low or their territories incredibly
small. "It is possible to bring them back," Pollock says, "but
it is quite work-intensive and financially expensive." Here, a
look at five species on the brink. Native to Spain and Portugal,
there are fewer than 250 of these felines left in the wild.
Habitat destruction has been a