The International Union for Conservation of Nature and Natural Resources lists endangered and vulnerable species. When a creature is endangered, there is a 20 percent or greater probability that it will go extinct with the next 20 years or five generations. For example, the giant panda's population in the wild is dwindling, despite efforts to save the species. Estimates are there are between 1,600 to 2,500 pandas left in a vanishing and increasingly fragmented habitat, the bamboo cloud forests of China.
A critically endangered species has a 50 percent or higher probability of extinction within 10 years or three generations. The leatherback turtle is one such species. The giant ocean-dwelling reptile, which returns to the same sandy beaches to nest generation after generation, is threatened by a loss of habitat, interference from human lights and activity, egg harvesting and illegal poaching, commercial fishing practices and increasing degradation of the ocean environment.
A vulnerable species is 10 percent or more likely to become extinct sometime within the next 100 years. The vividly multicolored military macaw is listed as vulnerable. The large parrot, which makes its home in the subtropical forests of Central and South America, is vulnerable due to rapid deforestation and poaching for the pet trade industry.
Odd as it seems, a species can be extinct in a number of ways, although all ways mean it is no longer viable on the planet. "Extinct" means no living member of the species exists anywhere in the world. But "extinct in the wild" means none of the species is alive outside captivity. "Globally extinct" means not found in the wild anywhere in the world and "locally extinct" means the species has vanished from an area. A "mass extinction" happens when a species is wiped out across geographic boundaries in a relatively short time, like the disappearance of the dinosaurs about 65 million years ago.