Critically Endangered Species

Updated: February 3, 2021
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Critically endangered species are at a very high risk of becoming extinct in the wild or extinct. For an animal to be added to the category, it must meet any of the following criteria regarding population or habitat decline:

Rapid Population Reduction

  • A taxon’s population size is reduced by 90 percent or more over 10 years or three generations, whichever is longer, and the reduction causes are understood, reversible, and have stopped. For example, let’s pretend there’s a bird species that traditionally had a population of 2000. Over 10 years, it drops to 200 because a logging company demolished its habitat. If laws are put in place that bar the logging company from continuing to fell trees in the habitat, then the IUCN will list it as “critically endangered” because the reason for the decline is understood and ceased.
  • A taxon’s population size is reduced by 80 percent or more over 10 years or three generations, whichever is longer, but the reduction cause may not be understood or reversible. For example, let’s say there’s a bird species that traditionally had a population size of 2000. Over 10 years, it drops to 400. However, scientists can’t figure out why they’re dying off. In this case, the IUCN would list it as “critically endangered” because the decimation is evident, but scientists can’t figure out why.
  • A taxon’s population size is reduced by 80 percent or more over 10 years or three generations, whichever is longer, and the animal is also battling habitat shrinkage or another threat.

Geographic Reduction

The area where a species can live is reduced to 100 square kilometers or less, or the area that the species currently and actually occupies is reduced to 10 square kilometers, and at least two of the following criteria are also met:

  • The population is known to exist in only one location.
  • Scientists observe or predict that the habitat will continue to shrink or be degraded, and there’s also a decline in subpopulations or the number of reproducing adults.
  • Scientists observe extreme fluctuations in the number of locations, subpopulations, or the number of reproducing adults.

Dangerously Low Number of Adults

  • A taxon’s population only has 250 or fewer adults left, and a 25 percent decline is anticipated within three years or one generation, whichever is longer. If none of the taxon’s subpopulations contain more than 50 adults, or 90 percent of the species’ adults live in one subpopulation, it will qualify as critically endangered.
  • Scientists observe extreme fluctuations in the number of mature adults in a given population.

Dangerously Low Overall Population Size

Only 50 or fewer individuals of a taxon remain.

Expected Rapid Decline

Research and studies indicate that there’s a 50 percent or greater chance that the taxon will be extinct in the wild within 10 years or three generations, whichever is longer.

How many species are currently critically endangered?

In the latest iteration of the list, 3,947 taxons — aka scientifically accepted units of species — are classified in the critically endangered category.

Critically Endangered Species

A Addax

The hooves of the addax are splayed and have flat, springy soles, one of the adaptations that help it walk over sand.

A Amur Leopard
Amur Leopard

The Amur leopard may be the rarest big cat on Earth!

A Angelshark

The angelshark’s range has contracted by more than 80% in the past century.

A Arabian Wolf
Arabian Wolf

Rare desert wolf

A Aruba Rattlesnake
Aruba Rattlesnake

This rattlesnake only lives on the island of Aruba.

A Baiji

Baijis use echolocation to find food in the Yangtze River.

A Balkan Lynx
Balkan Lynx

The Balkan lynx communicates mostly with its ears

A Bass

Prized by sport fishers for their size and strength

A Beluga Sturgeon
Beluga Sturgeon

The beluga sturgeon is one of the largest bony fish in the world!

A Black Rhinoceros
Black Rhinoceros

Horns can grow to 1.5m!

A Blobfish

One of the ugliest creatures in existence!

A Bongo

Long and heavy spiralled horns!

A Bornean Orang-utan
Bornean Orang-utan

Known to use large leaves as umbrellas!

A Borneo Elephant
Borneo Elephant

The smallest species of elephant!

A Canadian Horse
Canadian Horse

Canadian horses are believed to generate more power per pound of body weight than any other horse breed in the world.

A Capuchin

Named after Capuchin friars.

A Chinese Alligator
Chinese Alligator

Unlike other alligators, the Chinese alligator is armored all over, even on its belly.

A Chinese Paddlefish
Chinese Paddlefish

The Chinese paddlefish is one the largest freshwater fish in the world

A Coelacanth

The coelacanth first evolved almost 400 million years ago.

A Cotton-top Tamarin
Cotton-top Tamarin

Found in tropical forest edges!

A Crocodylomorph

Crocodylomorphs include extinct ancient species as well as 26 living species today.

A Cross River Gorilla
Cross River Gorilla

Less than 300 remaining!

A Desert Wolf
Desert Wolf

These tiny wolves prefer to cohabitate in pairs or groups of three (generally two males and a female).

A Douc

When these monkeys want to mate, they wiggle their eyebrows.

A Eagle Ray
Eagle Ray

Majestic underwater bird like fish

A Eastern Gorilla
Eastern Gorilla

The largest primate in the world!

A Egyptian Tortoise
Egyptian Tortoise

The Egyptian tortoise is one of the smallest tortoise species in the world.

A Finch

Finches have strong, conical bills that help them break open tough seeds that many other birds cannot.

A Freshwater Eel
Freshwater Eel

Freshwater eels are actually catadromous, meaning they migrate to saltwater to spawn

A Gazelle

Named for the Arabic word for love poems

A Gharial

Found in the murky waters of Northern India!

A Golden Lancehead
Golden Lancehead

Golden lancehead snakes climb trees to prey on birds.

A Goliath Grouper
Goliath Grouper

Massive reef fish with a strong tail

A Gooty Sapphire Tarantula
Gooty Sapphire Tarantula

They can run up a tree trunk surprisingly fast.

A Great Hammerhead Shark
Great Hammerhead Shark

Great hammerhead sharks have a 360 view because their eyes are situated on the ends of their mallet-like heads.

A Grouper

Many grouper can change their sex, and it is always from female to male.

A Hornbill

The bird has a massive horn on its bill!

A Houdan Chicken
Houdan Chicken

The Houdan chicken has a round, fluffy crest and five toes on each foot!

A Ivory-billed woodpecker
Ivory-billed woodpecker

The ivory-billed woodpecker can drill into wood with its sharp beak

A Jamaican Iguana
Jamaican Iguana

Almost went extinct for 40 years

A Javan Rhinoceros
Javan Rhinoceros

Only has a 25cm long horn!

A Kouprey

The kouprey is one of the rarest mammals in the world

A Lineback Cattle
Lineback Cattle

The lineback cattle has been an integral part of rural New England society for more than 200 years!

A Loris

Like all lorises, slow loris has a cute wide-eyed look, but it also has a venomous sting that can rot human flesh. 

A Marsican Brown Bear
Marsican Brown Bear

They do not fall completely asleep during hibernation but wake up from time to time during the winter to walk around.

A Mekong Giant Catfish
Mekong Giant Catfish

The Mekong giant catfish is the largest purely freshwater fish in the world

A Monte Iberia Eleuth
Monte Iberia Eleuth

The smallest frog in the Northern Hemisphere!

A Onagadori Chicken
Onagadori Chicken

The Onagadori, the chicken with the world's longest tail, was declared a Natural Monument of Japan in 1952.

A Orangutan

Shares 97% of its DNA with humans!

A Orinoco Crocodile
Orinoco Crocodile

Orinoco crocodiles are the largest predators in South America; they're also going extinct!

A Pied Tamarin
Pied Tamarin

Only found in one area of Brazil!

A Radiated Tortoise
Radiated Tortoise

The most protected tortoise in the world!

A Red-Headed Vulture
Red-Headed Vulture

Not exclusively carrion eaters, these birds are also opportunistic hunters

A Red Wolf
Red Wolf

Only 100 in the wild!

A Saiga

Large noses help filter out dust

A Sandpiper

Some sandpipers can migrate more than 8,000 miles without stopping!

A Saola

Only known to science since 1992!

A Sawfish

Sawfish teeth keep growing as the fish gets older

A Scrotum Frog
Scrotum Frog

The frog's ears are underdeveloped, and if it hears it probably does so through its lungs.

A Sehuencas Water Frog
Sehuencas Water Frog

Thought extinct in the wild from 2009 to 2019

A Sturgeon

Large species can swallow whole salmon

A Sumatran Elephant
Sumatran Elephant

Less than 2,000 left in the wild!

A Sumatran Orang-utan
Sumatran Orang-utan

Known to make mental maps of the forest!

A Sumatran Rhinoceros
Sumatran Rhinoceros

The smallest species of rhino!

A Swallow

swallows have aerodynamic bodies for hunting in flight

A Tamarin

These tiny yet intelligent monkeys often give birth to fraternal twins.

A Tapanuli Orang-utan
Tapanuli Orang-utan

Inhabits an isolated mountain range in northwestern Sumatra!

A Vaquita

Smallest cetacean in the ocean

A Viper

Vipers are one of the most widespread groups of snakes and inhabit most

A Western Gorilla
Western Gorilla

There are two sub-species!

A Western Lowland Gorilla
Western Lowland Gorilla

One of the great apes!

A Yokohama chicken
Yokohama chicken

Yokohama chickens have snow white feathers with tails reaching up to 4 feet in length.

List of Critically Endangered Species

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