# Fauna of the United States

The fauna of the United States of America is all the animals living in the Continental United States and its surrounding seas and islands, the Hawaiian Archipelago, Alaska in the Arctic, and several island-territories in the Pacific and in the Caribbean. The U.S. has many endemic species found nowhere else on Earth. With most of the North American continent, the U.S. lies in the Nearctic, Neotropic, and Oceanic faunistic realms, and shares a great deal of its flora and fauna with the rest of the American supercontinent.
An estimated 432 mammal species comprise the fauna of the continental U.S. There are more than 800 species of bird and more than 100,000 known species of insect. There are 311 known reptiles, 295 amphibians and 1154 known fish species in the U.S. Known animals that exist in all of the lower 48 states include white-tailed deer, bobcat, raccoon, muskrat, striped skunk, barn owl, American mink, American beaver, North American river otter and red fox. The red-tailed hawk is one of the most widely distributed hawks not only in the U.S., but in the Americas.
Huge parts of the country with the most distinctive indigenous wildlife are protected as national parks. In 2013, the U.S. had more than 6770 national parks or protected areas, all together more than 1,006,619 sq. miles (2,607,131 km$^2$). The first national park was Yellowstone National Park in the state of Wyoming, established in 1872. Yellowstone National Park is widely considered to be the finest megafauna wildlife habitat in the U.S. There are 67 species of mammals in the park, including the gray wolf, the threatened lynx, and the grizzly bear.

## Western United States

The ecoregions and ecology found in the Western United States are extremely varied. For instance, large areas of land are made up of everything from sand dunes in the Central Basin and Range ecoregion, which makes up much of the State of Nevada, to the ecology of the North Cascades in Washington state, which has the largest concentration of active alpine glaciers in the lower 48. The densely forested areas found in Northern California, Oregon, Washington, Idaho, and Montana have mostly species adapted to living in temperate climates, while Southern California, Nevada, Arizona, southern Utah, and New Mexico have a fauna resembling its position in the dry deserts with temperature extremes.
The western continental coast of the U.S. varies from a colder climate in the north to a warmer climate in the south. While few species live throughout the entire West Coast, there are some, such as the bald eagle, that inhabit both the Alaskan Aleutian Islands and the California Channel Islands. In most of the contiguous Western U.S., mule deer, white-tailed antelope squirrels, cougars, American badgers, coyotes, hawks and several species of snake and lizard are common.
While the American black bear lives throughout the U.S., brown bears and grizzly bears are more common in the northwest and in Alaska. Along the West Coast there are several species of whales, sea otters, California sea lions, eared seals and northern elephant seals. In the dry, inland desert areas of states such as California, Nevada, Arizona and New Mexico there are some of the world's most venomous lizards, snakes and scorpions. The most notorious might be the Gila monster and Mohave rattlesnake, both found in deserts in the Southwest. The Sonoran Desert has eleven species of rattlesnakes - more than anywhere else in the world.
Along the southwestern border there are jaguars and ocelots. Other mammals include the Virginia opossum, which occurs throughout California and coastal areas in Oregon and Washington. The North American beaver and mountain beaver live in forested areas of Washington, Oregon and Northern California. The kit fox lives throughout Arizona, New Mexico and Utah, while the gray fox occurs throughout the Western U.S.
The red fox occurs mostly in Oregon and Washington, while the island fox is a native to six of the eight Channel Islands in Southern California. These islands are also famous for their marine life and endemic species such as the Channel Islands spotted skunk, Garibaldi, island fence lizard, island scrub jay, bald eagle, and their non-native Catalina Island bison herd. The raccoon and spotted skunk occur throughout the Western U.S., while the ring-tailed cat occurs throughout Arizona, New Mexico, Western Texas, Utah, Colorado, and most of California. The American black bear occurs in most western states, including Washington, Oregon, California, Arizona and Colorado.

### Channel Islands

The Channel Islands National Park consists of five of the eight California Channel Islands. The Channel Islands are part of one of the richest marine biospheres of the world. Many unique species of plants and animals are endemic to the Channel Islands, including fauna such as the island fox, Channel Islands spotted skunk, island scrub jay, ashy storm-petrel, island fence lizard, island night lizard, Channel Islands slender salamander, Santa Cruz sheep, San Clemente loggerhead shrike and San Clemente sage sparrow. Other animals in the islands include the California sea lion, California moray, bald eagle, Channel Islands spotted skunk and the non-native Catalina Island bison herd.

## Southern United States

The South has a large variety of habitats that range from the Mississippi River basin in Arkansas and Mississippi to the Southern Appalachian Mountains. As far north as the hills of Tennessee and Virginia, all the way down to the Everglades in the southern end of Florida. From the eastern-most point on the Outer Banks of North Carolina, as far west as the deserts and prairies of West Texas and Oklahoma. The warmer climate allows for rich biodiversity ranging from cypress swamps in Louisiana to the thick bays and the longleaf pine biome of the South Carolina Lowcountry. It is riddled along the way with countless salt marshes in every coastal state from the Carolinas, through Georgia to Texas, including the Mobile Delta that lies in the borders of Alabama.
The Southern United States is home to a multitude of reptiles and amphibians. The American alligator lives in much of the South - including every coastal state from North Carolina to Texas, along with the inland states of Arkansas and Tennessee- while the less widespread American crocodile is only found in southern Florida. The Alligator snapping turtle and more than forty other species of turtle are found in the southern U.S. including the eastern box turtle, red-eared slider, and the softshell turtle. Snakes in the region include the eastern copperhead, eastern diamondback rattlesnake, timber rattlesnake, pigmy rattlesnake, cottonmouth, and eastern coral snake, all of which are venomous. Some of the other reptiles and amphibians thriving in the South include the Carolina anole, razor-backed musk turtle, broad-headed skink, American bullfrog, southern toad, spring peeper and the coal skink.
Mammals of the region include the elk, the largest of which that was wiped out in the 1800s, but has been reintroduced and is making promising recoveries in Virginia, North Carolina, Tennessee, and Arkansas. There still remain resident populations in parts of Texas and Oklahoma. The American black bear is native to much of the South, but are prevalent in Virginia, the Carolinas, Tennessee, Georgia, Florida, Arkansas, and Oklahoma. The Florida panther is the largest feline in the South and is exclusive to the wetlands of South Florida. White-tailed deer, bobcat, coyote, wild boar, red and grey fox are other mammals that inhabit parts of every state in the region. Wild horses roam parts of the South in small groups, which are remnants of horses brought by settlers in the 1400s and 1500s. These are mostly in coastal habitats.
Many water-dwelling mammals inhabit the South including the American beaver, muskrat, river otter, and nutria, which is an invasive species and has decimated plant life in the swamps of Louisiana. Weasels and mink also prefer being near water. Rabbits are common in the South; the eastern cottontail is found throughout the region, while the desert cottontail and black-tailed jackrabbit is primarily found in Texas, and Oklahoma. The swamp rabbit is found in wetlands of states like Mississippi, Alabama, Louisiana and Arkansas, while the marsh rabbit resides along the coastal regions of the Carolinas, Georgia, Florida, and Alabama. Squirrels are also abundant. The eastern grey squirrel and eastern fox squirrel can both be found in every southern state. The southern range of the American red squirrel dips into the higher elevations of Virginia and North Carolina. Other common mammals are the Virginia opossum, raccoon, striped and spotted skunk, groundhog and in parts of the South, the nine-banded armadillo.
There are over 1,100 species of bird in the Southern U.S. ranging from upland birds, to waterfowl. The South is home to many coastal birds including gulls, rails, gallinules, skimmers, grebes, sandpipers, cranes, and herons. Upland birds include wild turkey and ruffed grouse. Various game bird species such as the bobwhite quail and the woodcock. The eastern whip-poor-will and the Chuck-will's-widow belong to the nighthawk family and are found in every southern state. Songbirds make up the largest portion of birds found in this region.

## Central United States

In the prairie in the Central United States live mostly animals adapted for living in grasslands. Indigenous mammals include the American bison, eastern cottontail, black-tailed jackrabbit, plains coyote, black-tailed prairie dog, muskrat, opossum, raccoon, prairie chicken, wild turkey, white-tailed deer, swift foxes, pronghorn antelope, the Franklin's ground squirrel and several other species of ground squirrels.
Reptiles include bullsnakes, common collared lizard, common snapping turtle, musk turtles, yellow mud turtle, painted turtle, western diamondback rattlesnake and the prairie rattlesnake. Some of the typical amphibians found in the region are the three-toed amphiuma, green toad, Oklahoma salamander, lesser siren and the plains spadefoot toad. In the Rocky Mountains and other mountainous areas of the inland is where the bald eagle is most observed, even though its habitat includes all of the Lower 48, as well as Alaska.
Rabbits live throughout the Great Plains and neighboring areas; the black-tailed jackrabbit is found in Texas, Oklahoma, Nebraska and Kansas, the white-tailed jackrabbit in the Dakotas, Minnesota and Wisconsin, the swamp rabbit in swampland in Texas, and the eastern cottontail is found in Texas, Oklahoma, Kansas, Nebraska, the Dakotas, and every state in the Eastern U.S.
The groundhog is widespread throughout Illinois, Iowa, Missouri, and Minnesota. Virginia opossum is found in states such as Missouri, Indiana, Iowa, Oklahoma, Nebraska and Kansas.
The nine-banded armadillo is found throughout the South and states such as Missouri, Kansas and Oklahoma. The muskrat is found throughout the Central U.S., excluding Texas, while the American beaver is found in every central state.
Maybe the most iconic animal of the American prairie, the American buffalo, once roamed throughout the central plains. Bison once covered the Great Plains and were critically important to Native-American societies in the Central U.S. They became nearly extinct in the 19th century, but have made a recent resurgence in the Great Plains. Today, bison numbers have rebounded to about 200,000; these bison live on preserves and ranches.
Some of the species that occupy every central state include the red fox, bobcat, white-tailed deer, raccoon, eastern spotted skunk, striped skunk, long-tailed weasel, and the American badger and beaver. The invasive wild boar is common in the South, while the American mink lives in every central state with the exception of Texas. The least weasel is found around the Great Lakes as well as states such as Nebraska, the Dakotas, Minnesota, Iowa, Illinois, Michigan, and Wisconsin.
The gray fox is found in Iowa, Missouri, Oklahoma, Texas and also around the Great Lakes region. The ring-tailed cat is found in the southern region, including in Texas, Missouri, and Oklahoma. There are many species of squirrels in the central parts of the U.S., including the fox squirrel, eastern gray squirrel, Franklin's ground squirrel, southern flying squirrel, and the thirteen-lined ground squirrel. Voles include the prairie vole, woodland vole and the meadow vole. The plains pocket gopher lives throughout the Great Plains. Shrews include the cinereus shrew, southeastern shrew, North American least shrew, and the Elliot's short-tailed shrew.

## Eastern United States

In the Appalachian Mountains and the Eastern United States are many animals that live in forested habitats. They include deer, rabbits, rodents, squirrels, hares, woodpeckers, owls, foxes and bears. The New England region is particularly famous for its crab and the American lobster living along most of the Atlantic Coast. The bobcat, raccoon and striped skunk live in every eastern state, while the American alligator lives in every coastal state between North Carolina and Texas.
Some species of mammals found throughout the Eastern U.S. includes the red fox and gray fox, the North American beaver, North American porcupine, Virginia opossum, eastern mole, coyote, white-tailed deer, American mink, North American river otter, and long-tailed weasel. The American black bear lives throughout most of New England, New York, New Jersey, Pennsylvania, Maryland, the Virginias, and parts of the Carolinas and Florida.
Shrews are common: the cinereus shrew, long-tailed shrew and American water shrew are widespread in the New England region, while the North American least shrew and southeastern shrew are common in the southeastern states. The American pygmy shrew, smoky shrew, and northern short-tailed shrew are found from the Appalachian Mountains to New England. The star-nosed mole lives throughout the Eastern U.S., while the hairy-tailed mole is more common from the Appalachians to New England in the north.
Hares are also common: the snowshoe hare thrives from the Appalachians to New England, the Appalachian cottontail is only found in the Appalachians, the New England cottontail is only found in New England, while the eastern cottontail is widespread throughout the east. While the white-footed mouse and muskrat are common throughout the east, with the exception of Florida, the meadow vole is found from the Appalachians to New England and the southern red-backed vole is found in New England.
The brown rat and the house mouse were both introduced and their habitat range throughout the Eastern U.S. Weasels such as the fisher and short-tailed weasel are found in the northeast. The eastern chipmunk, fox squirrel, eastern gray squirrel and the woodchuck are found throughout the region, while the southern flying squirrel and northern flying squirrel are more common in the southeast, the American red squirrel is more common in the northeast. The least weasel is native to the Appalachian Mountains.
The wild boar is the wild ancestor of the domestic pig and has spread through much of the southeastern region as an invasive species. The Canada lynx is found in parts of New England. Species of bats found throughout the east includes the eastern pipistrelle, silver-haired bat, eastern red bat, hoary bat, big brown bat, little brown bat, northern long-eared myotis, and in most regions the eastern small-footed myotis, gray bat and Indiana bat.
Of the marine life, the harbor seal is the most widely distributed species of seal and found along the east coast, while the hooded seal, bearded seal, grey seal, ringed seal, and harp seal are found in the northwest. Whales are common along the Atlantic coastline. Whale species found along the entire coastline includes the Gervais' beaked whale, common minke whale, fin whale, sei whale, blue whale, humpback whale, sperm whale, dwarf sperm whale, pygmy sperm whale, killer whale, Cuvier's beaked whale, True's beaked whale, and the Blainville's beaked whale.
The northern bottlenose whale and the long-finned pilot whale are also common along the New England coast. Dolphins are common; species found along the entire coastline includes the Risso's dolphin, short-beaked common dolphin, striped dolphin, Atlantic spotted dolphin and the common bottlenose dolphin. Dolphin species found in New England include white-beaked dolphin and Atlantic white-sided dolphin, while species roaming the southeastern parts of the coastline include the Fraser's dolphin, pantropical spotted dolphin, Clymene dolphin, spinner dolphin, and the rough-toothed dolphin.
Several sea turtles live along the Atlantic coast, including the hawksbill sea turtle, Kemp's ridley sea turtle, and loggerhead sea turtle. The green sea turtle and leatherback sea turtle are more common species along the southeastern coastline. Land turtles and tortoises found throughout most of the Eastern United States are the common snapping turtle, painted turtle, spotted turtle, diamondback terrapin, spiny softshell turtle, eastern mud turtle, northern red-bellied cooter, common musk turtle, eastern box turtle, and the yellow- and red-eared slider. While common species in the northeast include Blanding's turtle, wood turtle, and bog turtle, common species in the southeastern U.S. include gopher tortoise, pond slider, Escambia map turtle, Barbour's map turtle, eastern river cooter, striped mud turtle, loggerhead musk turtle, and the Florida softshell turtle. The smooth softshell turtle is for instance found in the Ohio River and the Allegheny River in Pennsylvania.
Some of the snake species found in much of the Eastern U.S. includes the eastern racer, De Kay's snake, northern copperhead, ringneck snake, timber rattlesnake, eastern hog-nosed snake, milk snake, northern water snake, western rat snake, northern redbelly snake, plainbelly water snake, midland water snake, scarlet kingsnake, common kingsnake, queen snake, smooth earth snake, ribbon snake, and the common garter snake. Snake species mostly found in the northeast includes the smooth green snake, northern ribbon snake, and the eastern worm snake.
Snakes limited to the southeast includes the southeastern crown snake, pinesnake, eastern diamondback rattlesnake, coral snake, pygmy rattlesnake, southern copperhead, water moccasin, eastern coral snake, eastern indigo snake, southern hognose snake, coachwhip snake, banded water snake, brown water snake, green water snake, Nerodia clarkii clarkii, salt marsh snake, mole kingsnake, pine woods snake, glossy crayfish snake, striped crayfish snake, short-tailed snake, swamp snake, rim rock crown snake, rough earth snake, southern black racer, rough green snake, western rat snake, eel moccasin, and the mud and corn snakes. The eastern fence lizard is common throughout the Eastern United States, with the exception of New York and New England.
The gray wolf once roamed the Eastern U.S., but is now extinct from this region. The eastern cougar as well was once as widespread as the cougar in the western parts of the country, but was deemed extinct by the U.S. Fish and Wildlife Service in 2011. Eastern elk once lived throughout the east, but was extirpated in the 19th century and declared as extinct by the U.S. Fish and Wildlife Service in 1880. Moose as well once roamed throughout the east, but is currently only found in northern New England. Due to its highly prized fur, the sea mink was hunted to extinction in 1903.

## Hawaiian Islands

Much of the fauna in Hawaii has developed special adaptations to their home and evolved into new species. Today, nearly 90% percent of the fauna in Hawaii are endemic, meaning that they exist nowhere else on Earth. Kauaʻi is home to the largest number of tropical birds, as it is the only island free of mongooses. The invasive Javan mongoose is widespread throughout the archipelago, except on the islands of Lanaʻi and Kauaʻi.
Famous birds include ʻiʻiwi, nukupuʻu, Kauaʻi ʻamakihi and ʻōʻū. Most of these birds are extinct. The hoary bat is found in the Kōkeʻe State Park on Kauaʻi, feral horses live in the Waipio Valley, feral cattle by the Mauna Kea, and the Australian brush-tailed rock-wallaby live by the Kalihi Valley on Oʻahu. The Hawaiian monk seal, feral goats, feral sheep, and feral pigs live throughout most of the archipelago.
In Hawaii, three species of sea turtles are considered native: honu, honu’ea and the leatherback sea turtle. Two other species, the loggerhead sea turtle and the olive ridley sea turtle, are sometimes observed in Hawaiian waters. The Hawaiian green sea turtle is the most common sea turtle in Hawaiian waters. As well as turtles, the sea life consist of more than forty species of shark and the Hawaiian spinner dolphin is widespread. Hawaii's coral reefs are home to over 5000 species, and 25 percent of these are found nowhere else in the world.

## Alaska

The wildlife of Alaska is abundant, extremely diverse and includes for instance polar bears, puffins, moose, bald eagles, Arctic foxes, wolves, Canadian lynx, muskox, snowshoe hare, mountain goats, walrus and caribou. Life zones in Alaska range from grasslands, mountains, tundra to thick forests, which leads to a huge diversity in terrain and geology throughout the state.
Alaska has also over 430 species of birds and the largest population of bald eagles in the nation. From pygmy shrews that weigh less than a penny to gray whales that weigh 45 tons, Alaska is the "Last Frontier" for animals as well as people. Many species endangered elsewhere are still abundant in Alaska.

### Aleutian Islands

The Aleutian Islands are home to an abundance of large bird colonies; more than 240 bird species inhabit Alaska's Aleutian Archipelago. Large seabird colonies are present on islands like Buldir Island, which has 21 breeding seabird species, including the Bering Sea-endemic red-legged kittiwake. Large seabird colonies are also present on Kiska Island, Gareloi Island, Semisopochnoi Island, Bogoslof Island, and several others.
The islands are also frequented by vagrant Asiatic birds, including the common rosefinch, Siberian rubythroat, bluethroat, lanceolated warbler, and the first North American record of the intermediate egret. Other animals in the Aleutian Chain include the Arctic fox, American mink, Porcupine caribou, northern sea otter, horned puffin, tufted puffin, Steller sea lion, spotted seal, ringed seal, northern fur seal and many more.

## Territories
### American Samoa

Because of its remote location, diversity among the terrestrial species is low. The archipelago has a huge variety in animals and more than 9,000 acres is a national park: National Park of American Samoa. The park stretches over three of the six islands in the archipelago: Tutuila, Ofu-Olosega and Ta‘ū. Eight mammal species have been recorded at American Samoa, of which none of them are critically endangered.
The mammals include three species of native bats, namely the Samoa flying fox, the insular flying fox and the Pacific sheath-tailed bat. The avifauna includes 65 species of bird where the more unusual distinctive ones are the blue-crowned lorikeet, the spotless crake, the many-colored fruit dove, the wattled honeyeater, tropical pigeons, the samoan starling, white tern, black noddy and the red-tailed tropicbird.
There are many reptiles in the islands, including five species of geckos, eight species of skinks and two species of snakes: the Pacific boa and the Australoasian blindsnake. The marine life is magnificent and much concentrated around the colorful coral reefs. The Samoan ocean is a home to sea turtles as hawksbill sea turtle, olive ridley sea turtle, leatherback sea turtle and the green sea turtle. Five species of dolphins live in the area: spinner dolphin, rough-toothed dolphin, bottlenose dolphin, pantropical spotted dolphin and striped dolphin.

### Guam

Shortly after World War II, the brown tree snake was introduced to the island of Guam and caused much of the endemic wildlife to become extinct. Due to an abundance of prey species and lack of predators, the brown tree snake's population exploded and reached nearly 13,000 snakes per square mile at most. Ten out of twelve endemic bird species, ten lizards and two bats all became extinct as a result of the introduction of the brown tree snake. In recent years, a lot has been done by the U.S. government to decrease the number of brown tree snakes on the island. For instance in 2013, a $1 million program by the U.S. Fish and Wildlife Service dropped more than 2000 mice filled with poison on the island. In 2013, more than two million brown tree snakes were estimated to be on the island. Other introduced species include the Philippine deer, the Asiatic water buffalo, the marine toad and the giant African land snail. Several native species of skinks, geckos and a monitor lizard are still found on the island.

### Northern Mariana Islands

The Commonwealth of Northern Mariana Islands is home to 40 indigenous and introduced bird species. Some endemic bird species are the Mariana fruit dove, the Mariana swiftlet, the Rota white-eye, the Tinian monarch, the bridled white-eye and the golden white-eye. Other common, but introduced species, include the collared kingfisher, the rufous fantail, the fairy tern and the uniform swiftlet. The Mariana fruit bat is endemic to both Guam and the Northern Mariana Islands. The sambar deer is the largest mammal and lives on several of the islands. The Mariana monitor, ranging up to 3 feet long, is also present on the island of Rota. The oceans are home to more than a thousand species of marine life, including for instance the coconut crabs, the mahi-mahi, the barracuda, tridacna, marlin and tuna.

### Puerto Rico

Puerto Rico has 349 bird species, 83 mammals, 25 amphibians, 61 reptiles and 677 species of fish. Birds found nowhere else on earth include for instance the Puerto Rican owl, the Puerto Rican woodpecker, the Puerto Rican tody, the green mango, the Puerto Rican emerald, the Puerto Rican lizard cuckoo, the Puerto Rican nightjar and many more. All current endemic 13 land mammals are bats, which includes for instance the greater bulldog bat, the Antillean ghost-faced bat and the Parnell's mustached bat. Extinct native mammals include the plate-toothed giant hutia and the Puerto Rican cave rat. Reptiles unique to Puerto Rico include the Puerto Rican boa, the guanica blindsnake, the Mona Island iguana, the Puerto Rican worm lizard, the Puerto Rican galliwasp and the Nichols’ dwarf gecko. Amphibians native to the island include the Puerto Rican crested toad, the common coqui, the locust coqui, the wrinkled coqui, the forest coqui, the elfin coqui and the bronze coqui. Endemic fish include the Puerto Rican snake eel and the Puerto Rico coralbrotula.

### Virgin Islands

The Virgin Islands National Park covers approximately 60% of the Island of St. John and nearly all of Hassel Island. The national park has more than 140 species of birds, 302 species of fish, 7 species of amphibians and 22 species of mammals. The tropical Virgin Islands are home to a huge variety of wildlife, including many unique species endemic to the archipelago. There are three species of sea turtles in the USVI that inhabit the local waters and utilize beaches for nesting: the green sea turtle, the hawksbill sea turtle and the leatherback sea turtle. Several species of sharks, manatees and dolphins roam the seas.

## List of species in the United States
### Mammals

| Common name | Binomial name | Family | Distribution area | Notes |
| ABC Islands bear | Ursus arctos sitkensis | Ursidae | ABC Islands | |
| Abert's squirrel | Sciurus aberti | Sciuridae | Western United States | |
| Agile kangaroo rat | Dipodomys agilis | Heteromyidae | South California | |
| Alaska marmot | Marmota broweri | Sciuridae | Alaska | |
| Alaska Peninsula brown bear | Ursus arctos gyas | Ursidae | Alaska Peninsula | |
| Alaska tiny shrew | Sorex yukonicus | Soricinae | Alaska | |
| Alaskan hare | Lepus othus | Leporidae | Alaska | |
| Alaskan tundra wolf | Canis lupus tundrarum | Canidae | Arctic Alaska | |
| Allen's big-eared bat | Idionycteris phyllotis | Vespertilionidae | mainly in Arizona; has been spotted in California, Colorado, Nevada, New Mexico, Utah | |
| American badger | Taxidea taxus | Mustelidae | Across the country except Alaska, Hawaii, New England Puerto Rico, Southern United States (excluding Texas) and the U.S. Virgin Islands | The Wisconsin state mammal |
| American bison | Bison bison | Bovidae | Alaska, Arizona and Montana | The Kansas, Oklahoma and Wyoming state mammal; the US national mammal |
| American black bear | Ursus americanus | Ursidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | The Alabama, Louisiana, New Mexico and West Virginia state mammal |
| American ermine | Mustela richardsonii | Mustelidae | Northeastern and Western United States | |
| American marten | Martes americana | Mustelidae | Across the country except Hawaii, Puerto Rico, Southwestern United States, Texas and the U.S. Virgin Islands | |
| American mink | Neogale vison | Mustelidae | Alaska, Michigan, New England, New York, Wisconsin | |
| American pika | Ochotona princeps | Ochotonidae | Western United States | |
| American pygmy shrew | Sorex hoyi | Soricinae | Alaska, the Appalachians, the Great Lakes, New England, the Rockies | |
| American red fox | Vulpes vulpen fulva | Canidae | Eastern United States | |
| American red squirrel | Tamiasciurus hudsonicus | Sciuridae | Alaska, Northeastern United States and the Rockies | |
| American shrew mole | Neurotrichus gibbsii | Talpinae | Pacific Coast | The smallest species of mole |
| American water shrew | Sorex palustris | Soricinae | Alaska, the Appalachians, Illinois, Michigan, Minnesota, New England, Western United States | The smallest mammalian diver |
| Antelope jackrabbit | Lepus alleni | Leporidae | Southern Arizona | |
| Antillean fruit-eating bat | Brachyphylla cavernarum | Mormoopidae | Puerto Rico, U.S. Virgin Islands | |
| Antillean ghost-faced bat | Mormoops blainvillei | Phyllostomidae | Puerto Rico | |
| Antillean manatee | Trichechus manatus manatus | Trichechidae | Puerto Rico | The largest sea cow species |
| Appalachian cottontail | Sylvilagus obscurus | Leporidae | The Appalachians | |
| Arctic fox | Vulpes lagopus | Canidae | Alaska | |
| Arctic ringed seal | Pusa hispida hispida | Phocidae | Alaska, New England | The most abundant and wide-ranging seal in the Northern Hemisphere |
| Arctic shrew | Sorex arcticus | Soricinae | Northern United States | |
| Arizona gray squirrel | Sciurus arizonensis | Sciuridae | Arizona | |
| Arizona myotis | Myotis occultus | Vespertilionidae | Southwestern United States | |
| Arizona pocket mouse | Perognathus amplus | Heteromyidae | Sonoran Desert | |
| Arizona shrew | Sorex arizonae | Soricinae | Arizona, New Mexico | |
| Atlantic white-sided dolphin | Lagenorhynchus acutus | Delphinidae | New England | |
| Attwater's pocket gopher | Geomys attwateri | Geomyidae | Texas Coastal Bend | |
| Avery Island white-tailed deer | Odocoileus virginianus mcilhennyi | Cervidae | Louisiana and South Texas | |
| Atlantic spotted dolphin | Stenella frontalis | Delphinidae | East Coast | |
| Bailey's pocket mouse | Chaetodipus baileyi | Heteromyidae | Arizona, California, New Mexico | |
| Baird's beaked whale | Berardius bairdii | Ziphiidae | West Coast | |
| Baird's pocket gopher | Geomys breviceps | Geomyidae | Arkansas, East Texas, Louisiana, Oklahoma | |
| Baird's shrew | Sorex bairdi | Soricinae | Oregon | |
| Baja pocket mouse | Chaetodipus rudinoris | Heteromyidae | Southern California and the Channel Islands | |
| Banner-tailed kangaroo rat | Dipodomys spectabilis | Heteromyidae | Southwestern United States | |
| Barren ground shrew | Sorex ugyunak | Soricinae | Alaska | |
| Bearded seal | Erignathus barbatus | Phocidae | Alaska | |
| Beech marten | Martes foina | Mustelidae | Wisconsin (introduced) | |
| Beluga whale | Delphinapterus leucas | Monodontidae | Alaska | |
| Beringian lemming | Lemmus nigripes | Cricetidae | Alaska | |
| Big brown bat | Eptesicus fuscus | Vespertilionidae | Contiguous United States | The District of Columbia state mammal |
| Big free-tailed bat | Nyctinomops macrotis | Molossidae | California, Nevada, Texas, Utah | |
| Blackbeard Island white-tailed deer | Odocoileus virginianus nigribarbis | Cervidae | Blackbeard Island National Wildlife Refuge | |
| Black-footed ferret | Mustela nigripes | Mustelidae | Western United States | |
| Black-tailed jackrabbit | Lepus californicus | Leporidae | Great Plains, Western and West North Central states; introduced in Maryland, New Jersey, and Virginia | |
| Black-tailed prairie dog | Cynomys ludovicianus | Sciuridae | Montana, North Dakota, South Dakota, Wyoming, Colorado, Nebraska, Kansas, Oklahoma, Texas, Arizona, and New Mexico | |
| Blainville's beaked whale | Mesoplodon densirostris | Ziphiidae | East and West Coast of the United States | |
| Blue whale | Balaenoptera musculus | Balaenopteridae | East and West Coast of the United States | |
| Bobcat | Lynx rufus | Felidae | Contiguous United States | The New Hampshire state wildcat |
| Botta's pocket gopher | Thomomys bottae | Geomyidae | Southwestern United States | |
| Bowhead whale | Balaena mysticetus | Balaenidae | Alaska | The Alaska state marine mammal |
| British Columbia red fox | Vulpes vulpen abietorum | Canidae | Alaskan Panhandle | |
| British Columbia wolf | Canis lupus columbianus | Canidae | Alaskan Panhandle, Alexander Archipelago | |
| Brush rabbit | Sylvilagus bachmani | Leporidae | The West Coast | |
| Bryde's whale | Balaenoptera brydei | Balaenopteridae | South Atlantic and Gulf of Mexico | |
| Bulls Island white-tailed deer | Odocoileus virginianus taurinsulae | Cervidae | Cape Romain National Wildlife Refuge | |
| California kangaroo rat | Dipodomys californicus | Heteromyidae | California, Oregon | |
| California sea lion | Zalophus californianus | Otariidae | West Coast | |
| Camas pocket gopher | Thomomys bulbivorus | Geomyidae | Willamette Valley | |
| Canadian lemming | Lemmus trimucronatus | Cricetidae | Alaska | |
| Canadian lynx | Lynx canadensis | Felidae | Alaska, Colorado, Idaho, Maine, Minnesota, Montana, Utah, Washington | |
| Canyon bat | Parastrellus hesperus | Vespertilionidae | Western United States | The smallest bat in the United States |
| Carabao | Bubalus bubalis kerabau | Bovidae | Guam | |
| Cave myotis | Myotis velifer | Vespertilionidae | Arizona, Kansas, Oklahoma, Texas | |
| Cascade golden-mantled ground squirrel | Callospermophilus saturatus | Sciuridae | The Cascades | |
| Cascade red fox | Vulpes vulpen cascadensis | Canidae | Washington | |
| California leaf-nosed bat | Macrotus californicus | Phyllostomidae | Sonoran and Mojave deserts | |
| California mule deer | Odocoileus hemionus californicus | Cervidae | California | |
| California myotis | Myotis californicus | Vespertilionidae | Western United States | |
| California pocket mouse | Chaetodipus californicus | Heteromyidae | Southern California | |
| California vole | Microtus californicus | Cricetidae | California and Oregon | |
| Carmen Mountains white-tailed deer | Odocoileus virginianus carminis | Cervidae | South Texas | |
| Central Texas pocket gopher | Geomys texensis | Geomyidae | Central Texas | |
| Chihuahuan pocket mouse | Chaetodipus eremicus | Heteromyidae | Southwestern United States | |
| Chisel-toothed kangaroo rat | Dipodomys microps | Heteromyidae | Arizona, California, Idaho, Nevada, Oregon, Utah | |
| Cinereus shrew | Sorex cinereus | Soricinae | Alaska, Northern United States, Northwestern United States | The most widely distributed shrew in North America |
| Clymene dolphin | Stenella clymene | Delphinidae | East Coast | |
| Coast mole | Scapanus orarius | Scalopinae | Pacific Northwest | |
| Cockrum's gray shrew | Notiosorex cockrumi | Soricinae | Arizona | |
| Collared peccary | Dicotyles tajacu | Tayassuidae | Arizona, New Mexico and Texas | |
| Collared pika | Ochotona collaris | Ochotonidae | Alaska | |
| Columbian black-tailed deer | Odocoileus hemionus columbianus | Cervidae | Kauai, Pacific Northwest | |
| Columbian white-tailed deer | Odocoileus virginianus leucurus | Cervidae | Oregon, Washington | |
| Common bottlenose dolphin | Tursiops truncatus | Delphinidae | East and California | The Florida and South Carolina state salt water mammal |
| Common dolphin | Delphinus delphis | Delphinidae | East and California | |
| Common minke whale | Balaenoptera acutorostrata | Balaenopteridae | East and West Coast of the United States | |
| Coues' white-tailed deer | Odocoileus virginianus couesi | Cervidae | Arizona | |
| Cougar | Puma concolor | Felidae | Western United States | The most widely distributed wild, terrestrial mammal in the Western Hemisphere |
| Coyote | Canis latrans | Canidae | Across the country | The South Dakota state mammal |
| Crawford's gray shrew | Notiosorex crawfordi | Soricinae | Southwestern United States | |
| Creeping vole | Microtus oregoni | Cricetidae | Pacific Northwest | |
| Cuvier's beaked whale | Ziphius cavirostris | Ziphiidae | East and West Coast of the United States | |
| Dakota white-tailed deer | Odocoileus virginianus dacotensis | Cervidae | Colorado, the Dakotas, Minnesota, Montana, Wyoming | |
| Dall Island black bear | Ursus americanus pugnax | Ursidae | Dall Island | |
| Dall Island brown bear | Ursus arctos dalli | Ursidae | Dall Island | |
| Dall sheep | Ovis dalli dalli | Bovidae | Alaska | |
| Dall's porpoise | Phocoenoides dalli | Phocoenidae | West Coast of the United States | |
| Dark kangaroo mouse | Microdipodops megacephalus | Heteromyidae | California and Nevada | |
| Desert bighorn sheep | Ovis canadensis nelsoni | Bovidae | Southwestern United States | The Nevada state mammal |
| Desert cottontail | Sylvilagus audubonii | Leporidae | Western United States | |
| Desert kangaroo rat | Dipodomys deserti | Heteromyidae | Southwestern United States | |
| Desert mule deer | Odocoileus hemionus eremicus | Cervidae | Southwestern United States | |
| Desert pocket gopher | Geomys arenarius | Geomyidae | New Mexico, Texas | |
| Desert pocket mouse | Chaetodipus penicillatus | Heteromyidae | Southwestern United States | |
| Douglas squirrel | Tamiasciurus douglasii | Sciuridae | Western United States | |
| Dugong | Dugong dugon | Dugongidae | The Northern Mariana Islands | |
| Dulzura kangaroo rat | Dipodomys simulans | Heteromyidae | California | |
| Dwarf shrew | Sorex nanus | Soricinae | Mountain States | |
| Dwarf sperm whale | Kogia sima | Kogiidae | East and West Coast of the United States | |
| Eastern black bear | Ursus americanus americanus | Ursidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | |
| Eastern cottontail | Sylvilagus floridanus | Leporidae | Eastern Midwestern, South-Central and Southwestern United States; introduced in New England, Oregon and Washington | The most common rabbit species in North America |
| Eastern gray squirrel | Sciurus carolinensis | Sciuridae | Eastern United States | |
| Eastern meadow vole | Microtus pennsylvanicus | Cricetidae | Northern United States and Mountain States | |
| Eastern mole | Scalopus aquaticus | Scalopinae | Eastern United States, Lower Midwest, Southern United States | |
| Eastern red bat | Lasiurus borealis | Vespertilionidae | Eastern United States and Midwestern United States | |
| Eastern small-footed myotis | Myotis leibii | Vespertilionidae | Eastern United States | |
| Eastern wolf | Canis lycaon | Canidae | Great Lakes, New England | |
| Elk | Cervus canadensis | Cervidae | Contiguous United States | |
| Elliot's short-tailed shrew | Blarina hylophaga | Soricinae | Arkansas, Colorado, Iowa, Kansas, Louisiana, Missouri, Nebraska, Oklahoma, Texas | |
| European hare | Lepus europaeus | Leporidae | New York (introduced) | |
| European red fox | Vulpes vulpen crucigera | Canidae | Across the country (introduced) | |
| Evening bat | Nycticeius humeralis | Vespertilionidae | Midwestern and Southern United States | |
| Everglades short-tailed shrew | Blarina peninsulae | Soricinae | Florida | |
| False killer whale | Pseudorca crassidens | Delphinidae | East and West Coast of the United States | |
| Fin whale | Balaenoptera physalus | Balaenopteridae | East and West Coast of the United States | |
| Fisher | Pekania pennanti | Mustelidae | Alaska, the Appalachians, Great Lakes, New England, Pacific Northwest | |
| Florida bonneted bat | Eumops floridanus | Molossidae | Florida | |
| Florida coastal white-tailed deer | Odocoileus virginianus osceola | Cervidae | Coasts of Alabama, Florida and Mississippi | |
| Florida manatee | Trichechus manatus latirostris | Trichechidae | Florida; has been spotted in New England, the Gulf of Mexico and near the confluence of the Wolf and Mississippi rivers in Memphis | The largest sea cow species; The Alabama and Florida state marine mammal |
| Florida panther | Puma concolor coryi | Felidae | Florida | The Florida state mammal |
| Florida salt marsh vole | Microtus dukecampbelli | Cricetidae | Florida | |
| Florida white-tailed deer | Odocoileus virginianus seminolus | Cervidae | Florida | |
| Fog shrew | Sorex sonomae | Soricinae | California, Oregon | |
| Fox squirrel | Sciurus niger | Sciuridae | Eastern and Midwestern United States | |
| Fraser's dolphin | Lagenodelphis hosei | Delphinidae | Gulf of Mexico and Florida | |
| Fresno kangaroo rat | Dipodomys nitratoides | Heteromyidae | San Joaquin Valley | |
| Fringed myotis | Myotis thysanodes | Vespertilionidae | Western United States | |
| Gervais's beaked whale | Mesoplodon europaeus | Ziphiidae | East Coast | |
| Ghost-faced bat | Mormoops megalophylla | Mormoopidae | South Texas | |
| Giant kangaroo rat | Dipodomys ingens | Heteromyidae | California | |
| Ginkgo-toothed beaked whale | Mesoplodon ginkgodens | Ziphiidae | California | |
| Glacier Bay water shrew | Sorex alaskanus | Soricinae | Alaska | |
| Golden-mantled ground squirrel | Callospermophilus lateralis | Sciuridae | Western United States | |
| Gray bat | Myotis grisescens | Vespertilionidae | East South Central States, Lower Midwest | |
| Gray fox | Urocyon cinereoargenteus | Canidae | Across the country | The Delaware state mammal |
| Gray seal | Halichoerus grypus | Phocidae | New England | |
| Gray-tailed vole | Microtus canicaudus | Cricetidae | Washington and Oregon | |
| Gray whale | Eschrichtius robustus | Eschrichtiidae | West Coast | The California state marine mammal |
| Great Basin pocket mouse | Perognathus parvus | Heteromyidae | Great Basin | |
| Great Plains wolf | Canis lupus nubilus | Canidae | Michigan, Minnesota, North Dakota, Wisconsin | |
| Greater bulldog bat | Noctilio leporinus | Noctilionidae | Puerto Rico, U.S. Virgin Islans | |
| Greater long-nosed bat | Leptonycteris nivalis | Phyllostomidae | Southern Arizona, south New Mexico, South Texas | |
| Grizzly bear | Ursus arctos horribilis | Ursidae | Alaska, Pacific Northwest | The Montana state mammal |
| Groundhog | Marmota monax | Sciuridae | Alaska, Eastern United States, Idaho | |
| Guadalupe fur seal | Arctocephalus townsendi | Otariidae | Channel Islands | |
| Gulf Coast kangaroo rat | Dipodomys compactus | Heteromyidae | Texas | |
| Gunnison's prairie dog | Cynomys gunnisoni | Sciuridae | Utah, Colorado, Arizona and New Mexico | |
| Haida ermine | Mustela haidarum | Mustelidae | Alexander Archipelago | |
| Haida Gwaii black bear | Ursus americanus carlottae | Ursidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | |
| Hairy-tailed mole | Parascalops breweri | Scalopinae | Northeastern United States; extends into the Mid-South | |
| Hall's pocket gopher | Geomys jugossicularis | Geomyidae | Colorado, Kansas, and Nebraska | |
| Harbor seal | Phoca vitulina | Phocidae | West and East Coast of the United States | The Rhode Island state marine mammal |
| Harbour porpoise | Phocoena phocoena | Phocoenidae | The Rhode Island East and West Coast of the United States | |
| Harris's antelope squirrel | Ammospermophilus harrisii | Sciuridae | Arizona, New Mexico | |
| Hawaiian hoary bat | Lasiurus semotus | Vespertilionidae | Hawaii | The Hawaii state land mammal |
| Hawaiian monk seal | Neomonachus schauinslandi | Phocidae | Hawaii | The Hawaii state mammal |
| Heermann's kangaroo rat | Dipodomys heermanni | Heteromyidae | California | |
| Hilton Head white-tailed deer | Odocoileus virginianus hiltonensis | Cervidae | Hilton Head Island | |
| Hispid pocket mouse | Chaetodipus hispidus | Heteromyidae | Great Plains | |
| Hoary bat | Lasiurus cinereus | Vespertilionidae | Across the country | |
| Hoary marmot | Marmota monax | Sciuridae | Alaska, Montana, Washington | |
| Hualapai mexican vole | Microtus mexicanus hualapaiensis | Cricetidae | Hualapai Mountains | |
| Hubb's beaked whale | Mesoplodon carlhubbsi | Ziphiidae | West Coast | |
| Humboldt's flying squirrel | Glaucomys oregonensis | Sciuridae | California, Nevada, Oregon, and Washington | |
| Humpback whale | Megaptera novaeangliae | Balaenopteridae | East and West Coast | The Hawaii state marine mammal |
| Hunting Island white-tailed deer | Odocoileus virginianus venatorius | Cervidae | Hunting Island | |
| Idaho pocket gopher | Thomomys idahoensis | Geomyidae | Idaho, Montana, Utah, Wyoming | |
| Indiana bat | Myotis sodalis | Vespertilionidae | Eastern and Southern United States | |
| Insular flying fox | Pteropus tonganus | Pteropodidae | American Samoa | |
| Insular myotis | Myotis insularum | Vespertilionidae | American Samoa | |
| Insular vole | Microtus abbreviatus | Cricetidae | St. Matthew Island and Hall Island | |
| Interior Alaskan wolf | Canis lupus pambasileus | Canidae | Alaska | |
| Inyo mule deer | Odocoileus hemionus inyoensis | Cervidae | Central California | |
| Inyo shrew | Sorex tenellus | Soricinae | California, Nevada | |
| Island fox | Urocyon littoralis | Canidae | Channel Islands | |
| Jamaican fruit bat | Artibeus jamaicensis | Phyllostomidae | Puerto Rico, U.S. Virgin Islands | |
| Kansas white-tailed deer | Odocoileus virginianus macrourus | Cervidae | Arkansas, Iowa, Kansas, Louisiana, Missouri, Nebraska, South Dakota and Texas | The Arkansas state mammal |
| Keen's myotis | Myotis keenii | Vespertilionidae | Alaska, Washington | |
| Kenai black bear | Ursus americanus perniger | Ursidae | Kenai Peninsula | |
| Kenai red fox | Vulpes vulpen kenaiensis | Canidae | Kenai Peninsula | |
| Key deer | Odocoileus virginianus clavium | Cervidae | Florida Keys | |
| Kit fox | Vulpes macrotis | Canidae | Southwestern United States | |
| Knox Jones's pocket gopher | Geomys knoxjonesi | Geomyidae | New Mexico and Texas | |
| Kodiak bear | Ursus arctos middendorffi | Ursidae | Kodiak Islands | The second largest species of bear after polar bears |
| Kodiak red fox | Vulpes vulpen harrimani | Canidae | Kodiak Island | |
| Leach's single leaf bat | Monophyllus redmani | Phyllostomidae | Puerto Rico | |
| Least weasel | Mustela nivalis | Mustelidae | Alaska, Great Plains, Northeastern United States | |
| Lesser long-nosed bat | Leptonycteris yerbabuenae | Phyllostomidae | Southern Arizona, South California, South New Mexico, | |
| Little brown bat | Myotis lucifugus | Vespertilionidae | Everywhere except Florida, Hawaii, Louisiana, Southwestern United States, Texas | |
| Little pocket mouse | Perognathus longimembris | Heteromyidae | Western United States | |
| Long-eared myotis | Myotis evotis | Vespertilionidae | Western United States | |
| Long-finned pilot whale | Globicephala melas | Delphinidae | East Coast | |
| Long-legged myotis | Myotis volans | Vespertilionidae | Western United States | |
| Long-tailed pocket mouse | Chaetodipus formosus | Heteromyidae | Arizona, California, Nevada and Utah | |
| Long-tailed shrew | Sorex dispar | Soricinae | Northeastern United States | |
| Long-tailed vole | Microtus longicaudus | Cricetidae | Western United States | |
| Long-tailed weasel | Neogale frenata | Mustelidae | The Contiguous United States | |
| Louisiana black bear | Ursus americanus luteolus | Ursidae | East Texas, Louisiana and Mississippi | |
| Lower Keys marsh rabbit | Sylvilagus palustris hefneri | Leporidae | Florida Keys | |
| Manitoban elk | Cervus canadensis manitobensis | Cervidae | North Carolina, North Dakota | |
| Mariana fruit bat | Pteropus mariannus | Pteropodidae | Guam, the Northern Mariana Islands | |
| Marsh rabbit | Sylvilagus palustris | Leporidae | Florida; coasts of the Carolinas | |
| Marsh shrew | Sorex bendirii | Soricinae | West Coast | |
| Mazama pocket gopher | Thomomys mazama | Geomyidae | Pacific Northwest | |
| Melon-headed whale | Peponocephala electra | Delphinidae | Gulf of Mexico | |
| Merriam's kangaroo rat | Dipodomys merriami | Heteromyidae | Southwestern United States | |
| Merriam's pocket mouse | Perognathus merriami | Heteromyidae | New Mexico, Oklahoma, Texas | |
| Merriam's shrew | Sorex merriami | Soricinae | Western United States | |
| Mexican fox squirrel | Sciurus nayaritensis | Sciuridae | Arizona | |
| Mexican free-tailed bat | Tadarida brasiliensis | Molossidae | Southern United States, Southwestern United States | The Oklahoma and Texas state flying mammal |
| Mexican gray squirrel | Sciurus aureogaster | Sciuridae | Florida Keys (introduced) | |
| Mexican ground squirrel | Ictidomys mexicanus | Sciuridae | New Mexico and Texas | |
| Mexican spiny pocket mouse | Heteromys irroratus | Heteromyidae | South Texas | |
| Mexican wolf | Canis lupus baileyi | Canidae | Arizona, New Mexico | |
| Miller's long-tongued bat | Glossophaga longirostris | Phyllostomidae | U.S. Virgin Islands | |
| Minor red bat | Lasiurus minor | Vespertilionidae | Puerto Rico | |
| Montane shrew | Sorex monticolus | Soricinae | Alaska, Western United States | Texas state flying mammal |
| Montane vole | Microtus montanus | Cricetidae | Western United States | |
| Moose | Alces alces | Cervidae | Alaska, Idaho, New England, New York, North Dakota, Oregon, the Rockies, Upper Peninsula of Michigan, Washington, Wisconsin, Wyoming | The tallest, largest and heaviest species of deer and the tallest and second largest mammal in North America; The Alaska state land mammal and the Maine state mammal |
| Mount Graham red squirrel | Tamiasciurus fremonti grahamensis | Sciuridae | Pinaleño Mountains | |
| Mount Lyell shrew | Sorex lyelli | Soricinae | Mount Lyell | |
| Mountain beaver | Aplodontia rufa | Aplodontiidae | California, Nevada, Oregon and Washington | |
| Mountain cottontail | Sylvilagus nuttallii | Leporidae | Western United States | |
| Mountain goat | Oreamnos americanus | Bovidae | Alaska, Colorado, Idaho, Montana, Nevada, Oregon, South Dakota, Utah, Washington, Wyoming | |
| Mountain pocket gopher | Thomomys monticola | Geomyidae | California and Nevada | |
| Mule deer | Odocoileus hemionus | Cervidae | Western United States | |
| Muskox | Ovibos moschatus | Bovidae | Alaska | |
| Narrow-faced kangaroo rat | Dipodomys venustus | Heteromyidae | California | |
| Nelson's collared lemming | Dicrostonyx nelsoni | Cricetidae | Alaska | |
| Nelson's pocket mouse | Chaetodipus nelsoni | Heteromyidae | New Mexico and Texas | |
| New England cottontail | Sylvilagus transitionalis | Leporidae | New England | |
| New Mexico black bear | Ursus americanus altifrontalis | Ursidae | Arizona, Colorado, New Mexico, Utah and West Texas | |
| New Mexico shrew | Sorex neomexicanus | Soricinae | New Mexico | |
| Nine-banded armadillo | Dasypus novemcinctus | Dasypodidae | Southern United States | The only species of armadillo that inhabits the United States; The Texas state small mammal |
| North American beaver | Castor canadensis | Castoridae | Across the counry | The New York and Oregon state mammal |
| North American cougar | Puma concolor couguar | Felidae | Western United States | |
| North American least shrew | Cryptotis parva | Soricinae | Central United States, Eastern United States | |
| North American porcupine | Erethizon dorsatum | Erethizontidae | Alaska, Contiguous United States except the South | |
| North American river otter | Lontra canadensis | Mustelidae | Alaska, Eastern United States, Northern California, Pacific Northwest | |
| North American water vole | Microtus pinetorum | Cricetidae | Northwestern United States | |
| North Atlantic humpback whale | Megaptera novaeangliae novaeangliae | Balaenopteridae | East Coast | |
| North Atlantic minke whale | Balaenoptera acutorostrata acutorostrata | Balaenopteridae | East Coast | |
| North Atlantic right whale | Eubalaena glacialis | Balaenidae | East Coast | The Georgia and Massachusetts state marine mammal and the South Carolina state migratory marine mammal |
| North Pacific fin whale | Balaenoptera physalus velifera | Balaenopteridae | West Coast | |
| North Pacific humpback whale | Megaptera novaeangliae kuzira | Balaenopteridae | West Coast | |
| North Pacific minke whale | Balaenoptera acutorostrata scammoni | Balaenopteridae | West Coast | |
| North Pacific right whale | Eubalaena japonica | Balaenidae | Alaska | |
| Northern Alaskan red fox | Vulpes vulpen alascensis | Canidae | Yukon Delta National Wildlife Refuge | |
| Northern blue whale | Balaenoptera musculus musculus | Balaenopteridae | Alaska, New England, West Coast | |
| Northern bog lemming | Synaptomys borealis | Cricetidae | Alaska, Idaho, Maine, Montana, New Hampshire, Vermont and Washington | |
| Northern bottlenose whale | Hyperoodon ampullatus | Ziphiidae | New England | |
| Northern broad-footed mole | Scapanus latimanus | Scalopinae | California, Nevada, Oregon | |
| Northern collared lemming | Dicrostonyx groenlandicus | Cricetidae | Alaska | |
| Northern elephant seal | Mirounga angustirostris | Phocidae | Alaska, West Coast, Northern Mariana Islands | |
| Northern fin whale | Balaenoptera physalus physalus | Balaenopteridae | East Coast and West Coast of the United States | |
| Northern flying squirrel | Glaucomys sabrinus | Sciuridae | Alaska, the Appalachians, Great Lakes, New England, and Western United States | |
| Northern fur seal | Callorhinus ursinus | Otariidae | Alaska, West Coast | |
| Northern long-eared bat | Myotis septentrionalis | Vespertilionidae | Eastern United States | |
| Northern plains red fox | Vulpes vulpen regalis | Canidae | Elk River | |
| Northern pocket gopher | Thomomys monticola | Geomyidae | Northwestern United States | |
| Northern red-backed vole | Clethrionomys rutilus | Cricetidae | Alaska | |
| Northern right whale dolphin | Lissodelphis borealis | Delphinidae | West Coast | |
| Northern short-tailed shrew | Blarina brevicauda | Soricinae | Central United States, Eastern United States | |
| Northern white-tailed deer | Odocoileus virginianus borealis | Cervidae | Northeastern United States | The Illinois, New Hampshire, Ohio, Pennsylvania and Wisconsin state mammal and the Michigan state game mammal |
| Northern yellow bat | Lasiurus intermedius | Vespertilionidae | Gulf Coast | |
| Northwestern white-tailed deer | Odocoileus virginianus ochrourus | Cervidae | Western United States | |
| Northwestern wolf | Canis lupus occidentalis | Canidae | Alaska, Northwestern United States | |
| Nutria | Myocastor coypus | Echimyidae | Contiguous United States (introduced) | |
| Ocelot | Leopardus pardalis | Felidae | Arizona and Texas | |
| Olived-backed pocket mouse | Perognathus fasciatus | Heteromyidae | Great Plains | |
| Olympic black bear | Ursus americanus altifrontalis | Ursidae | Pacific Northwest | |
| Olympic marmot | Marmota olympus | Sciuridae | Olympic National Park | |
| Olympic shrew | Sorex rohweri | Soricinae | Olympic National Park | |
| Orca | Orcinus orca | Delphinidae | East and West Coast of the United States | The Washington state marine mammal |
| Ord's kangaroo rat | Dipodomys ordii | Heteromyidae | The Great Plains and the Great Basin | |
| Oregon pronghorn | Antilocapra americana oregona | Antilocapridae | Oregon | |
| Ornate shrew | Sorex ornatus | Soricinae | California | |
| Ozark big-eared bat | Corynorhinus townsendii ingens | Vespertilionidae | Arkansas, Missouri and Oklahoma | |
| Pacific common seal | Phoca vitulina richardii | Phocidae | West Coast | |
| Pacific marten | Martes caurina | Mustelidae | Western United States | |
| Pacific sheath-tailed bat | Emballonura semicaudata | Emballonuridae | American Samoa, Guam | |
| Pacific shrew | Sorex pacificus | Soricinae | Oregon | |
| Pacific white-sided dolphin | Lagenorhynchus acutus | Delphinidae | West Coast | |
| Pale kangaroo mouse | Microdipodops pallidus | Heteromyidae | California and Nevada | |
| Pallid bat | Antrozous pallidus | Vespertilionidae | Western United States | The state bat of California |
| Panamint kangaroo rat | Dipodomys panamintus | Heteromyidae | The Mojave Desert | |
| Pantropical spotted dolphin | Stenella attenuata | Delphinidae | East Coast | |
| Parnell's moustached bat | Pteronotus parnellii portoricensis | Mormoopidae | Puerto Rico | |
| Perrin's beaked whale | Mesoplodon perrini | Ziphiidae | California | |
| Philippine deer | Rusa marianna | Cervidae | Guam, the Northern Mariana Islands | |
| Plains bison | Bison bison bison | Bovidae | Alaska, Arizona and Montana | |
| Plains pocket gopher | Geomys bursarius | Geomyidae | Great Plains | |
| Plains pocket mouse | Perognathus flavescens | Heteromyidae | Central and Western United States | |
| Pocketed free-tailed bat | Nyctinomops femorosaccus | Molossidae | Arizona, California, New Mexico, Texas | |
| Polar bear | Ursus maritimus | Ursidae | Arctic Alaska | The largest bear species |
| Porcupine caribou | Rangifer arcticus arcticus | Cervidae | Alaska | |
| Prairie shrew | Sorex haydeni | Soricinae | Midwestern United States | |
| Prairie vole | Microtus ochrogaster | Cricetidae | Central United States | |
| Preble's shrew | Sorex preblei | Soricinae | Great Basin | |
| Pribilof Island shrew | Sorex hydrodromus/pribilofensis | Soricinae | Pribilof Islands | |
| Pronghorn | Antilocapra americana | Antilocapridae | Arizona, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Northern California, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington and Wyoming | Τhe fastest land mammal in the Western Hemisphere |
| Pygmy killer whale | Feresa attenuata | Delphinidae | East Coast | |
| Pygmy rabbit | Brachylagus idahoensis | Leporidae | Great Basin | The world's smallest rabbit |
| Pygmy sperm whale | Kogia breviceps | Kogiidae | East and West Coast of the United States | |
| Raccoon | Procyon lotor | Procyonidae | Across the country except Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands | The Tennessee state mammal and the Oklahoma state furbearer |
| Rafinesque's big-eared bat | Corynorhinus rafinesquii | Vespertilionidae | Southeastern United States | |
| Red fox | Vulpes vulpen | Canidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | |
| Red fruit bat | Stenoderma rufum | Phyllostomidae | Puerto Rico, U.S. Virgin Islands | |
| Red tree vole | Arborimus longicaudus | Cricetidae | California and Oregon | |
| Red wolf | Canis rufus | Canidae | Southeastern United States | |
| Reindeer | Rangifer tarandus | Cervidae | Alaska, Idaho, Montana and Washington | |
| Rhesus macaque | Macaca mulatta | Cercopithecidae | Florida, South Carolina, Puerto Rico | |
| Ribbon seal | Histriophoca fasciata | Phocidae | Alaska | |
| Rice's whale | Balaenoptera ricei | Balaenopteridae | Gulf of Mexico | |
| Ringed seal | Pusa hispida | Phocidae | Alaska, New England | |
| Ringtail | Bassariscus astutus | Procyonidae | Southwestern United States, West South Central states | The Arizona state mammal |
| Rio Grande ground squirrel | Ictidomys parvidens | Sciuridae | New Mexico and Texas | |
| Risso's dolphin | Grampus griseus | Delphinidae | East and West Coast of the United States | |
| Robust cottontail | Sylvilagus holzneri | Leporidae | Arizona, New Mexico, West Texas | |
| Rock pocket mouse | Chaetodipus intermedius | Heteromyidae | Southwestern United States | |
| Rock vole | Microtus chrotorrhinus | Cricetidae | The Appalachians and New England | |
| Rocky Mountains bighorn sheep | Ovis canadensis canadensis | Bovidae | The Rockies and Northwestern United States | The Colorado state mammal |
| Rocky Mountain elk | Cervus canadensis nelsoni | Cervidae | The Rockies | The Utah state mammal |
| Rocky Mountains mule deer | Odocoileus hemionus hemionus | Cervidae | The Rockies | |
| Roosevelt elk | Cervus canadensis roosevelti | Cervidae | Kodiak Archipelago, Pacific Northwest | |
| Rough-toothed dolphin | Steno bredanensis | Delphinidae | East and West Coast of the United States | |
| Sagebrush vole | Lemmiscus curtatus | Cricetidae | Western United States | |
| Saint Lawrence Island shrew | Sorex jacksoni | Soricinae | St. Lawrence Island | |
| Samoa flying fox | Pteropus samoensis | Pteropodidae | American Samoa | |
| San Joaquin antelope squirrel | Ammospermophilus nelsoni | Sciuridae | San Joaquin Valley | |
| San Joaquin kit fox | Vulpes macrotis mutica | Canidae | Central California | |
| San Joaquin pocket mouse | Perognathus inornatus | Heteromyidae | California | |
| Sand Hills pocket gopher | Geomys lutescens | Geomyidae | Colorado, Nebraska, South Dakota, and Wyoming | |
| Sea otter | Enhydra lutris | Mustelidae | Alaska, the West Coast | |
| Sei whale | Balaenoptera borealis | Balaenopteridae | East and West Coast of the United States | |
| Selkirk Mountains caribou | Rangifer arcticus montanus | Cervidae | Idaho, Montana, Washington | |
| Seminole bat | Lasiurus seminolus | Vespertilionidae | Southern United States | |
| Short-finned pilot whale | Globicephala macrorhynchus | Delphinidae | East and West Coast of the United States | |
| Sierra Nevada bighorn sheep | Ovis canadensis sierrae | Bovidae | The Sierra Nevada | |
| Sierra Nevada red fox | Vulpes vulpen necator | Canidae | The Cascades and the Sierra Nevada | |
| Silky pocket mouse | Perognathus flavus | Heteromyidae | Southwestern United States | |
| Silver-haired bat | Lasionycteris noctivagans | Vespertilionidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | |
| Singing vole | Microtus miurus | Cricetidae | Alaska | |
| Sitka black-tailed deer | Odocoileus hemionus sitkensis | Cervidae | Alaskan Panhandle | |
| Smoky shrew | Sorex fumeus | Soricinae | Northeastern United States | |
| Snowshoe hare | Lepus americanus | Leporidae | Alaska, the Appalachians, the Cascades, Michigan, Minnesota, New England, the Rockies, the Sierra Nevada, Wisconsin | |
| Sonoma tree vole | Arborimus pomo | Cricetidae | Northern California | |
| Sonoran pronghorn | Antilocapra americana sonoriensis | Antilocapridae | Sonoran Desert | |
| Sooty mustached bat | Pteronotus quadridens | Mormoopidae | Puerto Rico | |
| Southeastern myotis | Myotis austroriparius | Vespertilionidae | Gulf Coast, Mid-South (region) | |
| Southeastern pocket gopher | Geomys pinetis | Geomyidae | Alabama, Georgia, and Florida | |
| Southeastern shrew | Sorex longirostris | Soricinae | Southeastern United States | |
| Southern bog lemming | Synaptomys cooperi | Cricetidae | Eastern and Midwestern United States | |
| Southern broad-footed mole | Scapanus occultus | Scalopinae | California | |
| Southern flying squirrel | Glaucomys volans | Sciuridae | Eastern United States | |
| Southern mule deer | Odocoileus hemionus fuliginatus | Cervidae | Southern California | |
| Southern pocket gopher | Thomomys umbrinus | Geomyidae | Arizona, New Mexico | |
| Southern red-backed vole | Clethrionomys gapperi | Cricetidae | Alaska, Arizona, Colorado, Delaware, Idaho, Kentucky, Maryland, Michigan, Minnesota, Montana, New England, New Jersey, New Mexico, New York, North Carolina, North Dakota, Oregon, Pennsylvania, South Dakota, Tennessee, Utah, Virginia, Washington, West Virginia, Wisconsin and Wyoming | |
| Southern short-tailed shrew | Blarina carolinensis | Soricinae | Southern United States, Illinois | |
| Southern yellow bat | Lasiurus ega | Vespertilionidae | Lower Rio Grande Valley | |
| Southwestern myotis | Myotis auriculus | Vespertilionidae | Arizona, New Mexico | |
| Southwestern red squirrel | Tamiasciurus fremonti | Sciuridae | Western United States | |
| Sowerby's beaked whale | Mesoplodon bidens | Ziphiidae | New England | |
| Sperm whale | Physeter macrocephalus | Physeteridae | East and West Coast of the United States | The Connecticut state mammal |
| Spinner dolphin | Stenella longistrosis | Delphinidae | East Coast | |
| Spiny pocket mouse | Chaetodipus spinatus | Heteromyidae | Arizona, California and Nevada | |
| Spotted bat | Euderma maculatum | Vespertilionidae | Western United States | |
| Spotted seal | Phoca largha | Phocidae | Alaska | |
| Squirrel monkey | Saimiri sciureus | Cebidae | Florida, Puerto Rico | |
| Star-nosed mole | Condylura cristata | Scalopinae | Atlantic Coast, Great Lakes, New England | |
| Stejneger's beaked whale | Mesoplodon stejnegeri | Ziphiidae | West Coast of the United States | |
| Steller sea lion | Eumetopias jubatus | Otariidae | Alaska, West Coast | The largest eared seal |
| Stephen's kangaroo rat | Dipodomys stephensi | Heteromyidae | Southern California | |
| Stoat | Mustela erminea | Mustelidae | Alaska, the Dakotas, Great Lakes, New England, Northeastern United States, and the Western United States (excluding Arizona, Nevada, New Mexico and South California) | |
| Stone's caribou | Rangifer arcticus stone | Cervidae | Alaska | |
| Strecker's pocket gopher | Geomys streckeri | Geomyidae | Texas | |
| Striped dolphin | Stenella coeruleoalba | Delphinidae | East and West Coast of the United States | |
| Swamp rabbit | Sylvilagus aquaticus | Leporidae | Southern United States | |
| Swift fox | Vulpes velox | Canidae | Colorado, Kansas, Montana, New Mexico, Oklahoma and Texas | |
| Taiga vole | Microtus xanthognathus | Cricetidae | Alaska | |
| Texas antelope squirrel | Ammospermophilus interpres | Sciuridae | Texas, New Mexico | |
| Texas kangaroo rat | Dipodomys elator | Heteromyidae | Oklahoma, Texas | |
| Texas pocket gopher | Geomys personatus | Geomyidae | Texas | |
| Texas white-tailed deer | Odocoileus virginianus texanus | Cervidae | Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas and Wyoming | The Nebraska state mammal and Oklahoma state game mammal |
| Thirteen-lined ground squirrel | Ictidomys tridecemlineatus | Sciuridae | Great Plains | |
| Townsend's big-eared bat | Corynorhinus townsendii | Vespertilionidae | Western United States | |
| Townsend's mole | Scapanus townsendii | Scalopinae | Coastal Pacific Northwest | The largest North American mole |
| Townsend's pocket gopher | Thomomys townsendii | Geomyidae | Northwestern United States | |
| Townsend's vole | Microtus townsendii | Cricetidae | Oregon and Washington | |
| Tricolored bat | Perimyotis subflavus | Vespertilionidae | Midwestern and Southern United States | |
| True's beaked whale | Mesoplodon mirus | Ziphiidae | East Coast | |
| Trowbridge's shrew | Sorex trowbridgii | Soricinae | Pacific Coast | |
| Tule elk | Cervus canadensis nannodes | Cervidae | California | |
| Tundra shrew | Sorex tundrensis | Soricinae | Alaska | |
| Unalaska collared lemming | Dicrostonyx unalascensis | Cricetidae | Umnak and Unalaska | |
| Underwood's bonneted bat | Eumops underwoodi | Molossidae | Arizona | |
| Utah prairie dog | Cynomys parvidens | Sciuridae | Utah | |
| Vagrant shrew | Sorex vagrans | Soricinae | Western United States | |
| Velvety free-tailed bat | Molossus molossus | Molossidae | Florida Keys, Puerto Rico | |
| Virginia big-eared bat | Corynorhinus townsendii virginianus | Vespertilionidae | Kentucky, North Carolina, Virginia and West Virginia | The Virginia state bat |
| Virginia opossum | Didelphis virginiana | Didelphidae | Eastern United States, Lower Midwest, Pacific Coast (introduced), Southern United States | The only marsupial that inhabits the United States; The North Carolina state marsupial |
| Virginia white-tailed deer | Odocoileus virginianus virginianus | Cervidae | Southeastern United States except Florida | The Georgia, Mississippi and South Carolina state mammal |
| Walrus | Odobenus rosmarus | Odobenidae | Alaska | |
| Wasatch Mountains red fox | Vulpes vulpen macroura | Canidae | Colorado, Idaho, Montana, Utah, Wyoming | |
| Western gray squirrel | Sciurus griseus | Sciuridae | Western United States | |
| Western heather vole | Phenacomys intermedius | Cricetidae | Western United States | |
| Western mastiff bat | Eumops perotis | Molossidae | Southwestern United States | |
| Western meadow vole | Microtus drummondii | Cricetidae | Midwestern and Western United States | |
| Western red-backed vole | Clethrionomys californicus | Cricetidae | California and Oregon | |
| Western red bat | Lasiurus frantzii | Vespertilionidae | Western United States | |
| Western small-footed myotis | Myotis ciliolabrum | Vespertilionidae | Great Plains, Western United States | |
| Western yellow bat | Lasiurus xanthinus | Vespertilionidae | Southwestern United States | |
| White-beaked dolphin | Lagenorhynchus albirostris | Delphinidae | New England | |
| White-eared pocket mouse | Perognathus alticola | Heteromyidae | Southern California | |
| White-footed vole | Arborimus albipes | Cricetidae | Northwestern United States | |
| White-sided jackrabbit | Lepus callotis | Leporidae | New Mexico | |
| White-tailed antelope squirrel | Ammospermophilus leucurus | Sciuridae | Southwestern United States | |
| White-tailed deer | Odocoileus virginianus | Cervidae | Contiguous United States | |
| White-tailed jackrabbit | Lepus townsendii | Leporidae | Upper Midwest and Western United States | |
| White-tailed prairie dog | Cynomys leucurus | Sciuridae | Utah, Colorado, Wyoming and Montana | |
| Wolf | Canis lupus | Canidae | Across the country except Hawaii, Puerto Rico and the U.S. Virgin Islands | |
| Wolverine | Gulo gulo | Mustelidae | Alaska; has been in various states of the West | The largest mustelid |
| Woodland vole | Microtus pinetorum | Cricetidae | Eastern United States | |
| Wyoming pocket gopher | Thomomys clusius | Geomyidae | Wyoming | |
| Yellow-bellied marmot | Marmota flaviventris | Sciuridae | Western United States | |
| Yellow-faced pocket gopher | Cratogeomys castanops | Geomyidae | Southwestern United States | |
| Yuma myotis | Myotis yumanensis | Vespertilionidae | Western United States | |

## Articles by area

* Fauna of Alabama
* Fauna of Alaska
* Fauna of Arizona
* Fauna of Arkansas
* Fauna of California
* Fauna of Colorado
* Fauna of Connecticut
* Fauna of Delaware
* Fauna of the District of Columbia
* Fauna of Florida
* Fauna of Georgia
* Fauna of Hawaii
* Fauna of Idaho
* Fauna of Illinois
* Fauna of Indiana
* Fauna of Iowa
* Fauna of Kansas
* Fauna of Kentucky
* Fauna of Louisiana
* Fauna of Maine
* Fauna of Maryland
* Fauna of Massachusetts
* Fauna of Michigan
* Fauna of Minnesota
* Fauna of Mississippi
* Fauna of Missouri
* Fauna of Montana
* Fauna of Nebraska
* Fauna of Nevada
* Fauna of New Hampshire
* Fauna of New Jersey
* Fauna of New Mexico
* Fauna of New York
* Fauna of North Carolina
* Fauna of North Dakota
* Fauna of Ohio
* Fauna of Oklahoma
* Fauna of Oregon
* Fauna of Pennsylvania
* Fauna of Rhode Island
* Fauna of South Carolina
* Fauna of South Dakota
* Fauna of Tennessee
* Fauna of Texas
* Fauna of Utah
* Fauna of Vermont
* Fauna of Virginia
* Fauna of Washington
* Fauna of West Virginia
* Fauna of Wisconsin
* Fauna of Wyoming

### Insular areas

* Fauna of American Samoa
* Fauna of Guam
* Fauna of the Northern Mariana Islands
* Fauna of Puerto Rico
* Fauna of the United States Virgin Islands