How do scientists determine what's endangered?
When reading newspapers and magazines, listening to the news or TV shows, or reports from scientists, we often hear the term "endangered species" used frequently. But what exactly is "endangered" and how is this determined as the status of a population of animals?
Worldwide, nearly 1,600 plant and animal species are designated as endangered and face extinction.* A conservative estimate is that one in five species existing today will disappear in 30 years (World Wildlife Fund). However, all is not lost! Increased understanding of this problem has produced innovative conservation programs that protect habitat and species.
When terms such as "endangered", "threatened" or "extinct" are used, they refer to the current state of conditions a population of a species exists in in the wild.
The International Union for Conservation of Nature (IUCN) and its "Red List" that categorizes the status of wild animal populations uses the following terms:
Extinct - No reasonable doubt that the last individual has died.
Extinct in the wild - Known only to survive in captivity or in an introduced population well outside the natural range.
Critically endangered - Facing an extremely high risk of extinction in the wild; based on a population reduction of 80 percent or more, a range reduced to 100 square kilometers (38.6 square miles) or less, or a 50 percent probability of extinction within 10 years (among other criteria).
Endangered - Facing a very high risk of extinction in the wild; based on a population reduction of 50 percent or more, a range reduced to 5,000 square kilometers (1,930 square miles) or less, or a 20 percent probability of extinction within 20 years (among other criteria).
Vulnerable - Facing a high risk of extinction in the wild; based on a population reduction of 30 percent or more, a range reduced to 20,000 square kilometers (7,722 square miles) or less, or a 10 percent probability of extinction within 100 years (among other criteria).
Threatened - Any of the three categories above.
Near threatened - Does not qualify for one of the other categories now, but is close to qualifying or is likley to qualify for one of them i the near future.
Least concern - Does not qualify for any of the categories, and is currently widespread or abundant.
Categories used for status on this site
Known only to survive in captivity or in an introduced population outside its natural range.
Facing an extremely high risk of extinction in the wild.
Facing a very high risk of extinction in the wild.
Facing a high risk of extinction in the wild.
Does not qualify for one of the other categoires, but is close to qualifying or likely to qualify in the near future.
Does not qualify for any other category and is currently widespread or abundant.
Not evaluated, or not enough data exists to make an accurate determination of status.
SPECIES SURVIVAL PLANS
Zoos are responding to species decline and are leading the way in preserving animal populations. Captive breeding of threatened and endangered animals is conducted through the Species Survival Plan (SSP). The goal of each SSP is to maintain and enhance genetic in order to maintain healthy captive populations. SSPs are coordinated through the Association of Zoos & Aquariums (AZA).
Learn more about Species Survival Plans at the Association of Zoos & Aquariums' website
ENDANGERED SPECIES AT THE ZOO
Bali mynah (Leucopsar rothschildi)
Blyth's tragopan (Tragopan blythii blythii)
Cabot’s tragopan (Tragopan caboti)
Gyrfalcon (Falco rusticolus)
Himalayan impeyan pheasant (Lophophorus impeyans)
Humboldt penguin (Spheniscus humboltdi)
Northern spotted owl (Strix occidentalis caurina)
Palawan peacock pheasant (Polyplectron emphanum)
Peregrine falcon (Falco peregrinus)
Red-crowned crane (Grus japonensis)
White eared pheasant (Crossoptilon crossoptilon)
White-naped crane (Grus vipio)
African elephant (Loxondonta africana)
Asian elephant (Elephas maximus)
Brown bear (grizzly) (Ursus arctos horribilis) **
Clouded leopard (Neofelis nebulosa)
Golden lion tamarin (Leontopithecus rosalia)
Jaguar (Panthera onca)
Lion-tailed macaque (Macaca silenus)
Lowland anoa (Bubalus depressicornis)
Malayan tapir (Tapirus indicus)
Ocelot (Leopardus (Felis) paradalis)
Orangutan (Pongo pygmaeus)
Red panda (Ailurus fulgens styani)
Red ruffed lemur (Varecia variegata rubra)
Siamang (Symphalangus syndactylus)
Sloth bear (Melursus ursinus)
Snow leopard (Uncia uncia)
Southern pudu (Pudu pudu)
Sumatran tiger (Panthera tigris sumatrae)
Visayan warty pig (Sus cebifrons)
Western lowland gorilla (Gorilla gorilla gorilla)
Wolf (Canis lupus)
Reptiles and Amphibians:
Aruba Island rattlesnake (Crotalus durissus unicolor)
Dumeril’s ground boa (Boa dumerili)
Egyptian tortoise (Testudo kleinmanni)
Indian rock python (Python molurus molurus)
Komodo dragon (Varanus komodensis)
Madagascar tree boa (Boa mandrita)
Oregon spotted frog (Rana pretiosa) **
Panamanian golden frog (Atelopus zeteki)
West African dwarf crocodile (Osteolaemus tetraspis tetraspis)
Western pond turtle (Emys marmorata)**
Yellow-spotted side-necked turtle (Podocnemis unifilis)
Tahitian tree snails (Partula nodosa) +
2 species of pitcher plants (Nepenthes spp.)
20+ species of orchids (Orchidaceae)
This list may change at any time.
** Listed as endangered in Washington state but not by IUCN, USFWS or CITES
+ Extinct in the wild