While our planet boasts incredible biodiversity, 99.9% of species that have ever existed on Earth are now extinct.
Of the remaining 8.7 million plant and animal species, 23,000 are considered to be threatened with extinction according to the International Union for Conservation of Nature (IUCN), due primarily to loss of habitat and loss of genetic variation – the latter of which allows animals to adapt to environmental changes.
Keep reading to learn about 26 of the most endangered species in the US.
Although extinct in the wild by 1980, the red wolf was reintroduced to North Carolina seven years later by the US Fish and Wildlife Service.
Prior to going extinct in the wild in 1980, red wolves – identified by the reddish fur behind their ears and along their necks and legs – were native to North Carolina, Tennessee, and Texas. In 1987, the United States Fish and Wildlife Service reintroduced the species to eastern North Carolina in an area spanning the Albermarle and Pamilico Sounds.
In adulthood, red wolves weigh an average of 45 to 80 pounds and stand 26 inches at the shoulder.
There are 41 Oahu tree snail species, and all are listed as federally endangered by the US Fish and Wildlife Service.
Oahu tree snails – any of 41 species belonging to the genus Achatinella – were once so common on the eponymous island that they factored into Hawaiian folklore and songs. Now,only 11 species can be found in the Aloha State, where the creatures live at elevations of more than 1,300 feet in mountainous dry to wet forests and shrublands.
The snails – which measure three quarters of an inch and feature varying shell patterns, colours, and shapes – graze on the fungus that coats the surface of native plant leaves. Hermaphroditic in adulthood, they have a long lifespan.
Once prized by collectors, their biggest threat is now habitat destruction and predation by rats and carnivorous snail species.
The Kemp’s ridley turtle is one of the most endangered sea turtle species in the world.
Found mainly along the Gulf of Mexico, some Kemp’s ridley turtles swim to the east coast of the United States, including the shore of South Carolina.
Due to the over-harvesting of its eggs, the Kemp’s ridley is one of the world’s most endangered sea turtle species. It’s also the smallest species – adults have a shell length of just two feet. Despite their small stature, these turtles can still weigh up to 100 pounds.
The cui-ui, a large sucker fish, is only found in Nevada.
The cui-ui, a large sucker fish, is found only in Nevada’s Pyramid Lake and lower Truckee River, where the species spawns in the spring. Due to its limited habitat,an area spanning about 3,100 miles, the IUCN Red List classifies the cui-ui as endangered.
With a lifespan of more than 40 years, this species can weigh over 7.5 pounds in adulthood.
The ‘akiapōlā‘au is a forest avian native to Hawaii’s Big Island — and only 1,900 birds of the species remain.
Native to the forests of Hawaii’s Big Island, the ‘akiapōlā’au measures between 4.5 and 5.5 inches and relies on its unique bill – a curved/straight combo – to pick insect larvae from tree branches.
The ‘akiapōlā’au population has declined due to deforestation and the proliferation of alien plants and animals. Only 1,900 birds of this species remain.
Found in the southern tip of the Sunshine State, there are only 100 to 180 Florida panthers in the wild.
Panthers were once found across the southeastern US, spanning from Florida to Mississippi to Arkansas. Now, the only known breeding population is in southern Florida, where there are between 100 to 180 of the wildcats.
As habitat generalists, panthers – which belong to the same subspecies as pumas, mountain lions, and cougars – are just as likely to live in forests, prairies, and swamps.
The Columbia Basin pygmy rabbit is the smallest rabbit species — and one of the most endangered.
True to its name, the Columbia Basin pygmy rabbit – which weighs less than a pound and measures between 9.3 to 11.6 inches long in adulthood – is the smallest rabbit species. It’s also one of the most endangered. As of 2001, fewer than 50 were found in the wild.
While the species once lived throughout the northwestern United States, its range is now limited to Washington State. The main reason for the pygmy rabbits’ decline is the large-scale destruction of their sagebrush habitat. They rely on sagebrush for both shelter and food.
The Eskimo curlew was last sighted with certainty in 1963 — and some scientists speculate it might already be extinct.
Listed as critically endangered on the IUCN Red List, the Eskimo curlew was last seen with certainty in 1963. Some scientists speculate it might already be extinct.
Historically, the birds ranged from breeding grounds in the Alaskan and Canadian Arctic to Argentina’s Pampas grasslands, where they would migrate each winter. One report from the mid-19th century detailed how a flock occupied 40 to 50 acres of ground in Nebraska.
Ramsey Canyon leopard frogs have been found at just five sites in Arizona, including backyard ponds.
Native to Arizona’s Huachuca Mountains, extant populations of Ramsey Canyon leopard frogs have been found at only five sites, backyard ponds included. As habitat generalists, these amphibians can thrive in aquatic areas of pine-oak, oak woodland, and semi-desert grassland environments.
Although they’re now protected in California and Mexico, giant sea bass are critically endangered due to overfishing.
Spanning from California’s Humboldt Bay to the tip of Baja California, giant sea bass are critically endangered due to overfishing. Since 1982, they have been protected in California. In Mexico, they have been protected since 1992.
While juveniles are found at depths of about 40 to 70 feet, where they swim around kelp beds, adults prefer depths of nearly 100 feet.
Staghorn coral has experienced a population reduction of more than 80% over the past 30 years.
Staghorn coral – found in shallow tropical reef ecosystems from Palm Beach, Florida, to Venezuela – has experienced a population reduction of more than 80% over the past 30 years.
Major threats to the species (and other corals) include disease and climate change.
The Franklin’s bumblebee was last sighted in 2006 by a retired entomologist.
Much of what we know about the Franklin’s bumblebee, which was last sighted in 2006, comes from a retired (and tireless) entomologist named Robbin Thorp. His unpublished reports indicate that populations have decreased drastically since 1998 – to such an extent that not a single one of the bees was spotted between 2004 and 2005.
This rare bumblebee – one of more than 20,000 apian species – is only found between southern Oregon and northern California.
In general, the largest threats to bumblebees include exotic diseases introduced via commercial greenhouses, habitat destruction, and agricultural pesticides.
There are fewer than 250 dusky gopher frogs, which are found only in Mississippi.
It’s estimated that there are fewer than 250 mature dusky gopher frogs, which live in stump holes and burrows in longleaf pine forests. You’ll find breeding adults and tadpoles in shallow, fishless emphemeral, and isolated wetlands.
Once spanning the coastal plain of the southern United States from eastern Louisiana to Alabama’s Mobile River delta, the species is now limited to Harrison County, Mississippi. As of 2003, these frogs have primarily been found in Glen’s Pond in De Soto National Forest.
Like sharks and rays, smalltooth sawfish are members of a cartilaginous group of fish called elasmobranchs.
Along with sharks, skates, and rays, sawfish are members of a cartilaginous group of fish called elasmobranchs. The oldest cousin of the sawfish we know today took to the waters 100 million years ago.
The smalltooth, found mainly in the peninsula of Florida, is one of two sawtooth species native to the US. It’s also found as far away as Honduras and Sierra Leone. Measuring between 18 and 25 feet long in adulthood, smalltooth sawfish can weigh up to 770 pounds.
Due to their size, smalltooth sawfish can damage fishing gear and pose a threat to fishermen. When they’re captured by mistake, they’re often killed. Juvenile fish, which live in shallow areas abundant in vegetation (such as mangrove forests), are imperiled by habitat loss.
The Mitchell’s satyr butterfly is found only in Michigan and Indiana, where it lives in rare wetlands known as fens.
Found only in Michigan and Indiana, the Mitchell’s satyr butterfly is restricted to rare wetlands known as fens. It can be identified by its wings, which feature orange-ringed black circular eyespots.
Habitat destruction is the main reason why the Mitchell’s satyr is endangered. Much of its wetland habitat has been drained and filled due to urban and agricultural development. Fens are also susceptible to pollution from pesticides, fertiliser, and other contaminants. Additionally, some populations might have been decimated by butterfly collectors.
Bog turtles are threatened by damage to their wetland habitat. They’re also in demand in the pet trade.
There are two separate populations of bog turtles, which live in marshes and swamps in regions ranging from the southeastern Appalachian foothills to western Massachusetts.
The biggest threat to the species is habitat destruction. Bog turtles are also in small but high demand in the pet trade.
California condors nearly perished for good in the 1980s, but an intensive captive breeding program brought them back from the brink of extinction.
By 1987, California condors – which have historically been found between British Columbia and Baja California – were extinct in the wild. That year, the last six wild members of the species were captured for a breeding recovery program. Thankfully, the program was successful, yielding a population of 223 birds by 2003.
The species’ decline has been attributed to lead poisoning (from the accidental ingestion of bullet fragments stuck in carcasses) and to reduced eggshell thickness related to ingesting the pesticide DDT.
Found in two counties in the Sunshine State, the Florida bonneted bat has one of the most restricted ranges of any bat species.
A federally endangered species, the Florida bonneted bat is found in two southern counties in the Sunshine State.
With a body length of up to 6.5 inches, this non-migratory bat can weigh between 1.2 and 1.7 ounces. The species makes up for its small stature with a 21-inch wingspan and an extendable tail that protrudes beyond its short tail membrane.
Caribbean electric rays can generate an electric shock of 14 to 37 volts.
The Caribbean electric ray (also known as the lesser electric ray) can generate an electric shock of 14 to 37 volts. Native to the beaches and coastal waters of the western Atlantic Ocean, this species is found between North Carolina and Argentina.
Despite their electrical defence mechanism, these rays are slow swimmers and can become ensnared as bycatch in fishing nets.
The island grey fox is found only on six of the California Channel Islands.
The IUCN classifies the island grey fox as near threatened, but this species – found only on six of the California Channel Islands – is relatively uncommon. Each island’s subspecies contains around 1,000 adult individuals.
Also known as the California Channel Island fox and the island fox, this vulpine was named a “rarest of the rare” species by the Wildlife Conservation Society.
The Ozark hellbender is a large, aquatic salamander found in Missouri and Arkansas.
The Ozark hellbender is a large, aquatic salamander that can survive for up to 30 years in the wild. Found only in southern Missouri and northern Arkansas, the species lives in the White River watershed.
In addition to ore and gravel mining, its habitat is harmed by nutrient and toxic runoff. The Missouri populations are also threatened by an infectious fungus.
Kanab ambersnails are found only in Utah and in Arizona’s Grand Canyon National Park.
Kanab ambersnails are an endangered mollusk found in Kanab, Utah, and in Arizona’s Grand Canyon National Park. They utilise wetland vegetation for food and shelter, receding into their shells during the winter.
A hermaphroditic species, these snails are capable of self-fertilization if they can’t find a mate.
Mississippi sandhill cranes are found only at a wildlife refuge in Jackson County, Mississippi.
Critically endangered, Mississippi sandhill cranes are found only at a wildlife refuge in Jackson County, Mississippi, where around 100 individuals remain.
Originally, the population’s range spanned along the Gulf coastal plain from southern Louisiana to the western Florida panhandle. Much of the species’ habitat was destroyed when the open pine savanna was converted to pine plantations following World War II.
North Atlantic right whales are one of the world’s largest animals — and only 300 to 400 of them remain.
With only around 450, the North Atlantic right whale is one of the most endangered whale species. Historically, right whales have been hunted for their oil and baleen. They’re also threatened by ship collisions and fishing nets.
Measuring up to 55 inches long and weighing up to 62 tons, right whales are one of the largest animals in the world.
The grotto sculpin is found in the caves of Perry County, Missouri.
The grotto sculpin, a tiny, cave-dwelling fish, is found only in Perry County, Missouri. A federally endangered species, the population is contained to five cave systems and two streams.
Water contamination poses the biggest threat to the species.
The salt marsh harvest mouse is native to the salt and brackish marshes near California’s San Francisco Bay.
This small rodent measures between 2.75 and 3 inches long and weighs less than an ounce.
Sign up here to get INSIDER’s favourite stories straight to your inbox.
Business Insider Emails & Alerts
Site highlights each day to your inbox.