States with the most endangered species

- Total endangered species: 6
- Notable species:
--- Jesup's milk-vetch (scientific name: Astragalus robbinsii var. jesupi)
--- Dwarf wedgemussel (scientific name: Alasmidonta heterodon, IUCN category: vulnerable)

The dwarf wedgemussel is a tiny freshwater mollusk, only one and a half inches long, that lives in streams and rivers. It spends the larval part of its life cycle in the gills of fish. Once found all along the East Coast from Canada to North Carolina, its population has declined in large part due to habitat loss and pollution.

- Total endangered species: 8
- Notable species:
--- Eskimo curlew (scientific name: Numenius borealis, IUCN category: critically endangered)
--- Steller's Eider (scientific name: Polysticta stelleri, IUCN category: vulnerable)
--- Polar bear (scientific name: Ursus maritimus, IUCN category: vulnerable)

While the Eskimo curlew has not officially been declared extinct, there hasn’t been a sighting of this bird since 1963. They once bred in Canada and wintered in South America, but were the victim of habitat degradation, overhunting, and the extinction of one of their important food sources: the Rocky Mountain locust.

- Total endangered species: 8
- Notable species:
--- Whooping crane (scientific name: Grus americana, IUCN category: endangered)
--- Poweshiek skipperling (scientific name: Oarisma poweshiek)

The Poweshiek skipperling is a small butterfly native to the North American tallgrass prairie. Its last official sighting in North Dakota was in 2001 and it’s now found only at a few sites in Canada, Wisconsin and Michigan. Zoos, including the Minnesota Zoo, are breeding them in captivity, in hopes of saving the species.

- Total endangered species: 8
- Notable species:
--- Sandplain gerardia (scientific name: Agalinis acuta)

The Sandplain gerardia, with brilliant pink flowers that bloom in August and September, grows in dry sandy soils from Massachusetts to Maryland. It has lost habitat to development and to trees and shrubs whose growth was formerly kept in check by fire. By 1988, the only population in Rhode Island was in a historic cemetery, but conservation efforts in the early 2000s created two additional sites where it now grows.

- Total endangered species: 11
- Notable species:
--- Canby's dropwort (scientific name: Oxypolis canbyi)
--- Swamp pink (scientific name: Helonias bullata)

Canby's dropwort is a flowering perennial that grows in a variety of coastal habitats but prefers areas that stay wet most of the year, so the species has been negatively affected by the loss and degradation of wetlands. It blooms from mid-July through September, and is critical to the reproduction of the black swallowtail butterfly. The butterflies lay their eggs on the plants, which then serve as food for the caterpillars and a place for them to cocoon.

- Total endangered species: 12
- Notable species:
--- Puritan tiger beetle (scientific name: Cicindela puritana, IUCN category: endangered)
--- Dwarf wedgemussel (scientific name: Alasmidonta heterodon, IUCN category: vulnerable)
--- Small whorled pogonia (scientific name: Isotria medeoloides, IUCN category: vulnerable)

The Puritan tiger beetle is found in only two widely-separated locations: the Chesapeake Bay in Maryland and along the Connecticut River in New England, but primarily in Connecticut. They’re threatened by the loss of their very-specialized habitat of sandy beaches along rivers, which have been affected by human use, including damming, flood control, and recreation. As their name suggests, tiger beetles are fast runners and aggressive predators on smaller insects.

- Total endangered species: 12
- Notable species:
--- Furbish lousewort (scientific name: Pedicularis furbishiae, IUCN category: endangered)

The Furbish lousewort grows along the Saint John River, which forms the border between Maine and Canada. It prefers north and northwest facing slopes, and requires a habitat that is regularly disturbed by the natural movement of the river. It was actually declared extinct in 1975 and then rediscovered the following year, and is threatened by human destruction of its specialized habitat.

- Total endangered species: 12
- Notable species:
--- Salt Creek Tiger beetle (scientific name: Cicindela nevadica lincolniana)
--- Blowout penstemon (scientific name: Penstemon haydenii)

The blowout penstemon is named for the habitat it grows in: blowouts are bare areas where the wind has eroded channels and deposited sand. Thought to be extinct in 1940, the plant was rediscovered in 1968 and over the last 20 years has been the subject of conservation efforts. Transplanted seedlings have increased the population, but its specialized habitat is threatened by a range of human factors, including livestock grazing and recreational use.

- Total endangered species: 12
- Notable species:
--- Jesup's milk-vetch (scientific name: Astragalus robbinsii var. jesupi)

Jesup's milk-vetch is found in only three areas along the Connecticut River in New England. It thrives in a challenging habitat of rocky outcrops that are icy in the winter, flood in the spring, and have wide temperature swings in the summer. It’s threatened by competition from invasive plant species and at risk from increasingly limited genetic diversity caused by the effect of climate change on its reproductive cycle.

- Total endangered species: 14
- Notable species:
--- Black-footed ferret (scientific name: Mustela nigripes, IUCN category: endangered)
--- Western prairie fringed Orchid (scientific name: Platanthera praeclara, IUCN category: endangered)

The Black-footed ferret was once abundant across the grasslands of North America along with its main prey, the prairie dog. In 1986, what were believed to be the last 18 individuals were taken into captivity for a breeding program that has successfully reintroduced over 4,000 animals. However, they are still endangered by destruction and fragmentation of their habitat, disease, and declining prairie dog populations.

- Total endangered species: 15
- Notable species:
--- Bruneau hot springsnail (scientific name: Pyrgulopsis bruneauensis, IUCN category: critically endangered)
--- Northern Idaho ground squirrel (scientific name: Urocitellus brunneus, IUCN category: endangered)
--- Bull trout (scientific name: Salvelinus confluentus, IUCN category: vulnerable)

The bull trout is a migratory fish that is native to Canada and the Pacific Northwest. They prefer cold, clean water, so are most often found in high mountain areas and can be quite large—the state record is 32 pounds. They’re threatened by competition from introduced species, blocked migratory routes, and habitat degradation, and while it’s still legal to fish for them, they must be released.

- Total endangered species: 15
- Notable species:
--- Neosho madtom (scientific name: Noturus placidus, IUCN category: near threatened)

The Neosho madtom is a tiny catfish, around 3 inches long. There are only four populations of the species left in the wild, and they are found mainly in the Neosho River in Kansas. They prefer swift shallow streams lined with gravel, and have been affected by gravel mining, dams, and runoff from feedlots. While certain areas in Kansas have been designated as critical habitats, there has been little other action to conserve the species.

- Total endangered species: 15
- Notable species:
--- Wyoming toad (scientific name: Bufo hemiophrys baxteri)
--- Kendall Warm Springs dace (scientific name: Rhinichthys osculus thermalis)
--- Desert yellowhead (scientific name: Yermo xanthocephalus)

Once abundant in the Laramie Plains of Wyoming, populations of the Wyoming toad crashed in the 1970s, and by the 1990s the species was thought to be nearly extinct. What were believed to be the last of the species were brought into a captive breeding program in 1993. Tens of thousands of captive-bred tadpoles and young toads have been released, but the wild population is not yet thought to be self-sustaining.

- Total endangered species: 16
- Notable species:
--- Meltwater lednian stonefly (scientific name: Lednia tumana)
--- Western glacier stonefly (scientific name: Zapada glacier

Stoneflies are aquatic and are unusual among insects, in that they emerge as adults in winter and early spring. These two species require very cold water and are found at high elevations, close to the source of melting snow and ice. This means that they are threatened by climate change: For example, most of the remaining glaciers where they are found in Glacier National Park are predicted to be gone by 2030.

- Total endangered species: 16
- Notable species:
--- Knieskern's beaked-rush (scientific name: Rhynchospora knieskernii)

The Knieskern's beaked-rush, a member of the sedge family, is unique to New Jersey. It lives in wetland habitats and as one of the first species to colonize bare ground, is intolerant of competition from other plants and is often found in areas disturbed by human activity, such as ditches and clay pits. As of May, New Jersey legislators were considering a bill that would give additional protections to endangered plants in the state.

- Total endangered species: 16
- Notable species:
--- Northeastern bulrush (scientific name: Scirpus ancistrochaetus, IUCN category: near threatened)
--- Clubshell (scientific name: Pleurobema clava, IUCN category: critically endangered)

The clubshell is a small mussel that lives buried in the sand and gravel at the bottom of streams. Its range has been reduced by 95%. As a sedentary filter-feeder, it’s sensitive to anything that disturbs the substrate or water quality, so it’s affected by human activity, including development and agricultural runoff. It’s also threatened by the accidentally-introduced non-native zebra mussel, which reproduces more quickly and suffocates them.

- Total endangered species: 17
- Notable species:
--- Northeastern bulrush (scientific name: Scirpus ancistrochaetus, IUCN category: near threatened)
--- Plymouth redbelly turtle (scientific name: Pseudemys rubriventris bangsi)
--- Northeastern beach tiger beetle (scientific name: Cicindela dorsalis dorsalis)

The northeastern beach tiger beetle spends its whole life on ocean beaches, preferring undisturbed locations with fine sand and natural dune systems. The larvae are voracious feeders that live in burrows that they move according to the season, where they lie in wait to lunge at prey including sand flies. Once abundant from Massachusetts to Virginia, the species is now found only at the extremes of its former range, including just three sites in Massachusetts. It’s threatened by shoreline development and recreational use of beaches, as well as pollution and erosion due to climate change.

- Total endangered species: 18
- Notable species:
--- Rusty patched bumble bee (scientific name: Bombus affinis, IUCN category: critically endangered)
--- Dakota skipper (scientific name: Hesperia dacotae, IUCN category: endangered)
--- Higgins eye (pearlymussel) (scientific name: Lampsilis higginsii, IUCN category: endangered)

While there’s plenty of news about the plight of the beloved honeybee, it’s less often noted that it is an introduced non-native species, managed by humans much like livestock. North America has many species of native bees that are also in trouble. The rusty patched bumble bee is one that is critically endangered. Once found across much of the U.S., its habitat has been reduced by farming and development, and it is likely affected by pesticides, disease, and climate change.

- Total endangered species: 19
- Notable species:
--- Minnesota dwarf trout lily (scientific name: Erythronium propullans)
--- Leedy's roseroot (scientific name: Rhodiola integrifolia ssp. leedyi)

The Minnesota dwarf trout lily is unique to the state—in fact it’s found on only 600 acres in a few counties. This spring-blooming woodland wildflower has probably always been rare, so conservation efforts focus on protecting its existing habitat from development, erosion, and human activity. About half of the sites where it is found are on protected land, but many populations are on private land held by owners that have agreed to protect this unique species.

- Total endangered species: 20
- Notable species:
--- Ouachita rock pocketbook (scientific name: Arkansia wheeleri)
--- Ozark big-eared bat (scientific name: Corynorhinus townsendii ingens)

The Ozark big-eared bat is a subspecies of the Townsend's big-eared bat that is found only in a few places in Oklahoma and Arkansas. It does not migrate and lives in caves year-round, so it is threatened by human disturbance, especially while it hibernates in the winter, which may cause a bat to lose too much of its body weight to survive until spring. Conservation efforts have included installing steel gates to keep people out of caves that are homes to their colonies.

- Total endangered species: 21
- Notable species:
--- Hay's Spring amphipod (scientific name: Stygobromus hayi, IUCN category: endangered)

The Hay's Spring amphipod is a tiny crustacean found only in Rock Creek Park in Maryland and the District of Columbia. Because it spends its whole life in underground springs, it’s colorless and blind, and highly susceptible to habitat disturbance, including flooding from urban runoff around the park.

- Total endangered species: 24
- Notable species:
--- Louisiana pinesnake (scientific name: Pituophis ruthveni, IUCN category: endangered)
--- Ringed map turtle (scientific name: Graptemys oculifera, IUCN category: vulnerable)

Once more widely found in Texas and Louisiana, the Louisiana pinesnake is now restricted to only about a third of its original distribution, and is considered one of the rarest snakes in North America. It’s threatened by loss of its pine savannah habitat, which has been nearly eliminated by logging, and by other human impacts, including frequently being killed by cars. It reproduces slowly, making it difficult for populations to recover. Conservation efforts include assistance for private landowners to manage habitats that support them.

- Total endangered species: 24
- Notable species:
--- Chittenango ovate amber snail (scientific name: Succinea chittenangoensis, IUCN category: data deficient)

The Chittenango ovate amber snail is found only at one waterfall in Chittenango State Park in New York State. Once abundant, the population was down to under 25 in 1990. It’s affected by water quality degradation from runoff from roads and farms, human disturbance, and competition from a closely-related species that is thought to have been introduced by accident. A captive breeding program has successfully released some snails into their native habitat.

- Total endangered species: 24
- Notable species:
--- Fassett's locoweed (scientific name: Oxytropis campestris var. chartacea)

Fassett's locoweed is found only in three counties in Wisconsin. It grows on open sandy shores of lakes when fluctuating water levels are low; in years with high water levels it may not appear. A project based at the University of Wisconsin is working to propagate seedlings and plant them in a suitable habitat.

- Total endangered species: 25
- Notable species:
--- Hungerford's crawling water beetle (scientific name: Brychius hungerfordi)
---    (scientific name: Mimulus michiganensis)
--- Dwarf lake iris (scientific name: Iris lacustris, IUCN category: near threatened)

The Dwarf lake iris is found only around the Great Lakes, growing close to the shoreline in sandy soil. It has lost habitat due to development for vacation homes and recreation, and associated road construction and chemical use. In addition, it is sold for gardening use and may be illegally collected from the wild.

- Total endangered species: 26
- Notable species:
--- Rayed bean (scientific name: Villosa fabalis, IUCN category: endangered)

The rayed bean is a small mussel, only about an inch and a half long. Once found in 115 locations in streams and lakes, it had lost 73 percent of its range—down to 32 locations—when it was listed as endangered in 2012. It’s been affected by pollution, competition from the invasive zebra mussel, and the construction of dams, which disrupt water flow, temperature, and river bottoms, and block the movement of fish that help move the mussels around.

- Total endangered species: 26
- Notable species:
--- Scioto madtom (scientific name: Noturus trautmani, IUCN category: extinct)

Only 18 individuals of this small catfish have ever been seen, all along the Big Darby Creek in central Ohio. It was last seen in the wild in 1957 and is likely extinct, but is still kept on the federal endangered species list so that if any populations were to be discovered they would be protected.

- Total endangered species: 29
- Notable species:
--- Diamond darter (scientific name: Crystallaria cincotta, IUCN category: critically endangered)

The only known population of the diamond darter is found in the Elk River in West Virginia, a biodiversity hotspot that is home to over 100 species of fish and 30 species of mussels. The small fish was once more widespread, but much of its habitat was destroyed by the construction of dams. The remaining habitat is threatened by human activities that affect water quality, including coal mining, oil and gas drilling, and recreational uses.

- Total endangered species: 30
- Notable species:
--- Columbia Basin pygmy rabbit (scientific name: Brachylagus idahoensis, IUCN category: least concern)
--- Island marble butterfly (scientific name: Euchloe ausonides insulanus)
--- Showy stickseed (scientific name: Hackelia venusta)

The last known wild population of this subspecies of pygmy rabbit was gone by 2004, probably due to habitat loss and fragmentation. The last 16 remaining in captivity became part of a breeding program, but because there were so few of them, it was necessary to crossbreed with another species of pygmy rabbit. The first wild litter from the reintroduction program was born in 2011, and the program concluded in 2012, when the last 14 remaining breeding adults and their offspring were reintroduced.

- Total endangered species: 33
- Notable species:
--- Knowlton's cactus (scientific name: Pediocactus knowltonii, IUCN category: critically endangered)
--- Gunnison sage-grouse (scientific name: Centrocercus minimus, IUCN category: endangered)
--- Whooping crane (scientific name: Grus americana, IUCN category: endangered)

Knowlton's cactus is found only in one small area on the border of New Mexico and Colorado. Its miniature size made it attractive to collectors and easy to conceal, so it was at one point reduced to only 1% of its original numbers due to poaching. Propagated specimens have been successfully transplanted to two new areas, but the species is still at risk from illegal collection and oil and gas development.

- Total endangered species: 34
- Notable species:
--- Benton County cave crayfish (scientific name: Cambarus aculabrum, IUCN category: critically endangered)
--- Hell Creek Cave crayfish (scientific name: Cambarus zophonastes, IUCN category: critically endangered)
--- Ivory-billed woodpecker (scientific name: Campephilus principalis, IUCN category: critically endangered)

The Ivory-billed woodpecker was once the third largest woodpecker in the world. After a steep decline in numbers due to destruction of its old-growth forest habitat, the last universally-accepted sighting of this bird was in 1944. After a report of a sighting in Arkansas in 2005, a search of 523,000 acres over eight states failed to produce definitive evidence of its survival. Additional sightings were reported in a journal publication in 2017, but many experts were unconvinced.

- Total endangered species: 34
- Notable species:
--- Illinois cave amphipod (scientific name: Gammarus acherondytes, IUCN category: endangered)

The Illinois cave amphipod is a tiny crustacean less than one inch long. Unique to Illinois, it is currently found in only three caves, half the number where it was originally known to exist. It requires cold, clean water, and is affected by human activities—such as the use of pesticides—that pollute the groundwater, so the increasing human population puts additional pressure on its survival. Since the species was listed as endangered, land has been acquired to protect its habitat.

- Total endangered species: 36
- Notable species:
--- Tumbling Creek cavesnail (scientific name: Antrobia culveri, IUCN category: endangered)
--- Niangua darter (scientific name: Etheostoma nianguae, IUCN category: vulnerable)

The tiny Tumbling Creek cavesnail is found in only one cave in Missouri and its numbers have declined by 99% since 1974. This aquatic snail is only 1/10 of an inch long, and while little is known about it, it is thought to be affected by declines in water quality due to factors such as erosion from overgrazing, agricultural runoff, and increasing development. An invasive crayfish reported in their habitat may prey on them.

- Total endangered species: 37
- Notable species:
--- Carolina heelsplitter (scientific name: Lasmigona decorata, IUCN category: critically endangered)
--- Miccosukee gooseberry (scientific name: Ribes echinellum)

The Miccosukee gooseberry, a perennial shrub, occurs in only two widely-distant locations—Jefferson County in Florida and McCormick County in South Carolina. The South Carolina population has been shown to have low genetic diversity, which affects its reproductive success. Browsing by deer is also a threat, as is competition from invasive species.

- Total endangered species: 41
- Notable species:
--- Rough popcornflower (scientific name: Plagiobothrys hirtus)
--- Columbian white-tailed deer (scientific name: Odocoileus virginianus leucurus)
--- Fender's blue butterfly (scientific name: Icaricia icarioides fenderi)

Fender's blue butterfly is found nowhere else than the upland prairies of the Willamette Valley in western Oregon. Thought to have gone extinct in 1937, it was rediscovered in 1989 and listed endangered in 2000. Its native prairie habitat has either been developed, or else the natural succession of disturbance and regrowth that it requires has been interrupted by fire suppression and other land management techniques. The encroachment of shrubs and trees shade out the native lupine plains that the butterfly depends on.

- Total endangered species: 41
- Notable species:
--- Pariette cactus (scientific name: Sclerocactus brevispinus, IUCN category: critically endangered)
--- Utah prairie dog (scientific name: Cynomys parvidens, IUCN category: endangered)

Prairie dogs used to inhabit the West in the hundreds of millions, and even the less-numerous Utah species was estimated to number 95,000 in the 1920s. Thought to be pests, they were reduced in number by poisoning and disease, and by 1972 only a little over 3,000 remained. Since their listing in 1973, reintroduction and transportation have increased their numbers, but some amount of regulated killing has been allowed, and continuing human population growth poses an ongoing threat.

- Total endangered species: 42
- Notable species:
--- Devils Hole pupfish (scientific name: Cyprinodon diabolis, IUCN category: critically endangered)
--- Pahrump poolfish (scientific name: Empetrichthys latos, IUCN category: critically endangered)
--- White River spinedace (scientific name: Lepidomeda albivallis, IUCN category: critically endangered)

The Devils Hole pupfish is so named because its behavior resembles frolicking puppies. It’s one of the rarest fish in the world, with one of the smallest ranges of any vertebrate: just the top 80 feet of a cavern in the Mojave desert, in waters that are 93 degrees and with oxygen levels almost too low for fish to survive. The population has been steeply declining since the 1990s, with a low of 35 fish reported at one point. While their habitat is now protected, the reason for their decline is still not clear.

- Total endangered species: 46
- Notable species:
--- Cumberlandian combshell (scientific name: Epioblasma brevidens, IUCN category: critically endangered)
--- Duskytail darter (scientific name: Etheostoma percnurum, IUCN category: critically endangered)
--- Cumberland elktoe (scientific name: Alasmidonta atropurpurea, IUCN category: endangered)

The Duskytail darter is a small bottom-dwelling fish that feeds on aquatic insects and is named for its habit of darting for cover when threatened. It was only discovered to occur in Kentucky in 1995, and some of the few populations found have already disappeared since then. They require clear river water, so have been threatened by pollution and siltation, and by dams' changing water levels. Some have been successfully introduced into additional locations in Tennessee as a result of conservation efforts.

- Total endangered species: 49
- Notable species:
--- Bayou darter (scientific name: Etheostoma rubrum, IUCN category: endangered)
--- Pearl darter (scientific name: Percina aurora, IUCN category: endangered)
--- Yellow-blotched map turtle (scientific name: Graptemys flavimaculata, IUCN category: vulnerable)

The yellow-blotched map turtle is found only in the Pascagoula River system in southern Mississippi. Its population has declined due to habitat loss, including silting, pollution, and the channeling of rivers for flood control. They are also impacted by collection for the pet trade and competition from invasive species.

- Total endangered species: 54
- Notable species:
--- Noel's amphipod (scientific name: Gammarus desperatus, IUCN category: critically endangered)
--- Texas hornshell (scientific name: Popenaias popeii, IUCN category: critically endangered)
--- Socorro springsnail (scientific name: Pyrgulopsis neomexicana, IUCN category: critically endangered)

Springsnails are a diverse group of aquatic invertebrates found in the western U.S. that are increasingly at risk due to threats to their habitat, including groundwater pumping and livestock grazing. New Mexico has nine species that are found nowhere else, and of these, the Socorro springsnail is the most endangered.

- Total endangered species: 67
- Notable species:
--- Appalachian elktoe (scientific name: Alasmidonta raveneliana, IUCN category: critically endangered)
--- Carolina heelsplitter (scientific name: Lasmigona decorata, IUCN category: critically endangered)
--- Cape Fear shiner (scientific name: Notropis mekistocholas, IUCN category: endangered)

The Cape Fear shiner is found only in the Cape Fear River Basin in central North Carolina. It’s a small, golden-scaled minnow only about 2 inches long. The removal of a dam in 2005 allowed previously-isolated populations to come together and opened up an additional habitat, and removal of additional dams is being considered. However, it continues to be under threat from degraded water quality and invasive predatory fish.

- Total endangered species: 69
- Notable species:
--- Bonytail (scientific name: Gila elegans, IUCN category: critically endangered)
--- Apache trout (scientific name: Oncorhynchus apache, IUCN category: critically endangered)
--- Three Forks springsnail (scientific name: Pyrgulopsis trivialis, IUCN category: critically endangered)

The Apache trout is the state fish of Arizona and one of only two trout native to the state. Once abundant, their numbers declined due to competition from other species that were introduced for sport fishing and habitat degradation. The first conservation steps were taken in the mid-1950s, when only 30 miles of habitat remained and the White Mountain Apache tribe closed fishing on tribal lands. In 1969, they were one of the first species to be federally recognized as endangered, and in 1975, they were one of the first to have its status improved to threatened.

- Total endangered species: 73
- Notable species:
--- Conasauga logperch (scientific name: Percina jenkinsi, IUCN category: critically endangered)
--- Altamaha spinymussel (scientific name: Elliptio spinosa, IUCN category: endangered)
--- Cherokee darter (scientific name: Etheostoma scotti, IUCN category: endangered)

The Conasauga logperch is one of the rarest members of the darter family in North America, found only in a 27-mile stretch of one river. Their numbers declined dramatically in the 2000s for reasons that are unclear, but are thought to be related to recent changes in local agriculture. In the early 2010s, hundreds of captive bred individuals were released to augment the population, and subsequent surveying has shown that they are successfully surviving in the wild.

- Total endangered species: 75
- Notable species:
--- Lee County cave isopod (scientific name: Lirceus usdagalun, IUCN category: endangered)
--- Madison Cave isopod (scientific name: Antrolana lira, IUCN category: vulnerable)
--- Shenandoah salamander (scientific name: Plethodon shenandoah, IUCN category: vulnerable)

The Shenandoah salamander is unique to Virginia, found only on three mountains in Shenandoah National Park. Despite living in a protected area, it’s subject to many threats resulting from human activity: Habitat in the park is being affected by soil acidification and invasive species, and climate change is likely to alter the cool mountain conditions it requires. Research is underway to determine how best to protect the species.

- Total endangered species: 102
- Notable species:
--- Hinckley oak (scientific name: Quercus hinckleyi, IUCN category: critically endangered)
--- Comanche Springs pupfish (scientific name: Cyprinodon elegans, IUCN category: endangered)
--- Devils River minnow (scientific name: Dionda diaboli, IUCN category: endangered)

The Hinckley oak is a short, shrubby, very ancient species—it is thought to have been common around 15,000 years ago when Texas had a wetter climate than it does today. Now its range is restricted to only three sites and it does not appear to be successfully reproducing in one of them.

- Total endangered species: 106
- Notable species:
--- Chucky madtom (scientific name: Noturus crypticus, IUCN category: critically endangered)
--- Cumberland pigtoe (scientific name: Pleurobema gibberum, IUCN category: critically endangered)
--- Purple bean (scientific name: Villosa perpurpurea, IUCN category: critically endangered)

The purple bean is a mussel named for the purple color on the inside of its shell. Freshwater mussels are affected by human activity that alters their habitat, including dam building and declining water quality. A captive breeding and reintroduction project is part of its recovery plan.

- Total endangered species: 133
- Notable species:
--- Fat threeridge (mussel) (scientific name: Amblema neislerii, IUCN category: critically endangered)
--- American alligator (scientific name: Alligator mississippiensis, IUCN category: least concern)

The American alligator has been around for 200 million years, but by the mid-20th century its numbers had dwindled because of people hunting for its hide. It was designated endangered in 1967, and became one of the first endangered species conservation successes in 1987, when it was declared fully recovered. It now thrives to the extent that sustainable harvesting is legal, the basis for a $14 million dollar industry in Florida.

- Total endangered species: 143
- Notable species:
--- Pygmy sculpin (scientific name: Cottus paulus, IUCN category: critically endangered)
--- Fanshell (scientific name: Cyprogenia stegaria, IUCN category: critically endangered)
--- Dromedary pearlymussel (scientific name: Dromus dromas, IUCN category: critically endangered)

The pygmy sculpin is unique to Alabama—in fact, found in just one place, Coldwater Spring. This tiny fish—just one and a half inches long—is one of the most-threatened species of fish in the state, largely due to the fact that it lives in just one place. While the water quality is currently still quite good, the surrounding area is at risk of loss of vegetation and other pressures that will affect it.

- Total endangered species: 282
- Notable species:
--- Catalina Island mountain-mahogany (scientific name: Cercocarpus traskiae, IUCN category: critically endangered)
--- Delta green ground beetle (scientific name: Elaphrus viridis, IUCN category: critically endangered)
--- Morro shoulderband snail (scientific name: Helminthoglypta walkeriana, IUCN category: critically endangered)

The Delta green ground beetle is thought to have once been more widespread in California, but is now found only in one county in the San Francisco Bay area. They depend on vernal pools, which are temporary ponds that exist only in the rainy season and are important habitat for many species—for example, many amphibians depend on them for reproduction. This kind of habitat has declined due to agricultural use, natural gas exploration, other human impacts, and invasive plant species, and they are also illegally taken by collectors.

- Total endangered species: 502
- Notable species:
--- Mauna Loa silversword (scientific name: Argyroxiphium kauense, IUCN category: critically endangered)
--- Kauai cave wolf or pe'e pe'e maka 'ole spider (scientific name: Adelocosa anops, IUCN category: endangered)
--- Hawaiian duck (scientific name: Anas wyvilliana, IUCN category: endangered)

The Hawaiian duck is unique to Hawaii. One unusual threat to this species is that it is hybridizing with closely-related domestic mallards that have been released into the wild. It’s also threatened by habitat loss and introduced predators, including rats, mongooses, dogs, and cats. Removal of feral mallards has kept one of its populations, on Kauai, fairly low in hybridization.