Animals that start with U make a short list, but the history behind it is long. It runs from a rhino-sized Eocene mammal that fueled a famous fossil feud to a prairie dog found in only one corner of the American West. U is one of the letters with the fewest species, so every entry has a story worth telling.
This article covers 18 animals beginning with U: primates, birds, fish, reptiles, insects, an extinct giant, and one dog breed. Sources disagree on the full roster. A-Z Animals lists 16, and other sites stretch past 40 by adding every obscure shrew and sunbird. The 18 here are the ones that come up most often in American classrooms, zoos, field guides, and pet shops.
Each entry covers where the animal lives, how people came to know it, and what it means for readers in the United States. Some are backyard neighbors. Others live in distant rainforests or only in the fossil record. If you are working through the alphabet, the animals that start with T make a good companion read.
| Animal | Type | Where It Lives |
|---|---|---|
| Uakari | Primate | Amazon Basin |
| Uaru Cichlid | Freshwater fish | Amazon Basin |
| Uguisu | Songbird | Japan and East Asia; introduced to Hawaii |
| Uinta Ground Squirrel | Rodent | Rocky Mountain states |
| Uintatherium | Extinct mammal | Eocene North America and China |
| Ulysses Butterfly | Insect | Australia and New Guinea |
| Umbrella Cockatoo | Parrot | Indonesia |
| Umbrella Squid | Cephalopod | Deep ocean waters |
| Umbrellabird | Songbird | Central and South America |
| Unau | Sloth | Northern South America |
| Underwing Moth | Insect | North America and Europe |
| Upland Sandpiper | Shorebird | North American grasslands |
| Ural Owl | Owl | Northern Europe and Asia |
| Urial | Wild sheep | Central and South Asia |
| Uromastyx | Lizard | North Africa and the Middle East |
| Urutu Snake | Pit viper | Southern South America |
| Utah Prairie Dog | Rodent | Southwestern and central Utah |
| Utonagan | Dog breed | United Kingdom origin |
1. Uakari
The uakari is the primate you remember for its face. It is a small primate with a red face that lives in the Amazon. The bald uakari (Cacajao calvus) has a hairless, scarlet head, a shaggy coat, and a short tail. The color comes from blood vessels close to the skin, and it fades when a monkey is sick.
Uakaris spend their lives in the forest canopy, often in flooded forest, and eat seeds and unripe fruit that most monkeys cannot crack. Conservation status varies by species. The bald uakari and the neblina uakari are listed as Vulnerable, while the golden-backed and Aracá uakaris are Least Concern, according to Active Wild.
US readers rarely see uakaris outside documentaries and a few specialist zoo exhibits. That scarcity is part of why the animal has such a hold on the imagination.
2. Uaru Cichlid
The uaru cichlid (Uaru amphiacanthoides) is a South American freshwater fish with a tall, disc-shaped body. Hobbyists often call it the triangle cichlid because of its profile. It comes from the Amazon Basin, and adults can reach about a foot long.
Uarus are known for parental care. Both parents guard the eggs, and the fry graze on mucus from the adults’ bodies for their first weeks. That habit puts them in the same behavioral club as discus fish, a better-known aquarium group.
In the United States, uarus turn up at specialty fish stores and cichlid clubs. They need a large tank, stable water, and a calm setup, because they are shy and can be bullied by more aggressive tank mates.
3. Uguisu
The uguisu, or Japanese bush warbler (Horornis diphone), is one of Japan’s most celebrated birds, though few people ever see one. It hides in dense scrub and is known almost entirely by its song, a whistled phrase that signals the start of spring. Japanese poetry has paired the bird with plum blossoms for more than a thousand years.
The bird also left a mark on the language. The soft olive-brown color uguisu-iro is named after its plumage, and English-language writers often call the bird a Japanese nightingale. Traditional beauty practice even used the droppings in facial treatments.
Americans can hear this bird without leaving the country. It was released on Oahu in the late 1920s and became established in Hawaii’s forests. For more feathered names, see these bird names that start with Z.
4. Uinta Ground Squirrel
The Uinta ground squirrel (Urocitellus armatus) lives in the meadows and sagebrush slopes of the northern Rocky Mountains, from Utah and Wyoming into Idaho and Montana. It is named for the Uinta Mountains, though its range extends well beyond them. Ranchers and hikers sometimes call it a “potgut” because of its round belly.
This squirrel lives on a tight schedule. It emerges from its burrow in spring, fattens up on grasses and wildflowers, and goes back underground to hibernate for much of the year. Many animals pause at the edge of a high meadow to stand on their hind legs and watch for hawks.
It shares its range with other western rodents on this list, including the Utah prairie dog. Visitors to Rocky Mountain trailheads and campgrounds often mistake it for a chipmunk.
5. Uintatherium
Uintatherium (Uintatherium anceps) is the only animal here that no one has ever seen alive. Its name means “Beast of the Uinta Mountains.” It stood about 1.5 meters (5 feet) at the shoulder, ran about 4 meters (13 feet) long, and weighed up to 2 tonnes, similar in size and shape to a rhinoceros. The resemblance is only skin deep, since the two are not closely related.
The skull is what made it famous. Males carried six knob-like ossicones on the skull, and the large upper canines superficially resembled those of saber-toothed cats. Despite its bulk, its brain was small relative to its body.
The history is as dramatic as the anatomy. Its Fort Bridger fossils in Wyoming became a focal point of the Bone Wars between Othniel Charles Marsh and Edward Drinker Cope. Specimens have been found in Wyoming and in Utah near the Uinta Mountains. Visitors can see a skeleton cast at the Utah Field House of Natural History State Park.
This was a world of early mammals that included the dawn horses, small forest browsers that were the distant start of the horse family. Anyone interested in ancient horse breeds and the deep history of horse breeds should start with these Eocene ancestors. Uintatherium lived through the Paleocene-Eocene thermal maximum, a period of some of the highest global temperatures in Earth’s history. Uintatheres went extinct toward the end of the Middle Eocene, for unknown reasons. The Uintatherium entry on Wikipedia details the fossil sites and the two recognized species.
6. Ulysses Butterfly
The Ulysses butterfly (Papilio ulysses) is a large swallowtail with wings of electric blue, edged in black. It lives in northeastern Australia, New Guinea, and nearby islands, which is why it is also called the blue mountain swallowtail. Its wingspan reaches roughly 4 inches.
The blue is structural color, created by microscopic scales that reflect light rather than by pigment. The underside is a dull brown, so the butterfly nearly vanishes when it folds its wings. Wildlife Explored lists it as an insect from Australasia.
Linnaeus described the species in 1758 and named it after the Roman form of Odysseus, in keeping with his habit of naming swallowtails for heroes of the Trojan War. The butterfly has since become a symbol of Queensland tourism. American visitors can see live Ulysses butterflies in some walk-through butterfly conservatories.
7. Umbrella Cockatoo
The umbrella cockatoo (Cacatua alba) is a white parrot from the Indonesian islands of North Maluku. Its crest is a fan of long white feathers that rises like an umbrella when the bird is excited or alarmed. Underneath the crest, the feathers of the wings and tail show a pale lemon yellow.
The species is common in American homes and rescues, and it is also the bird most associated with surrender to shelters. Cockatoos can live for decades, so a bird bought as a pet may outlast the person who bought it. Many are noisy and need hours of daily attention.
In the wild, trapping for the pet trade and habitat loss have driven the umbrella cockatoo to Endangered status on the IUCN Red List. That is one reason US parrot rescues urge buyers to adopt rather than buy.
8. Umbrella Squid
The umbrella squid is the vaguest entry on this list, because the name does not point to a single species. It is generally used for deep-sea squid with webbed arms that flare out like an open umbrella. Some lists put the umbrella squid among sea and ocean animals that start with U. The family most often linked to the name, Histioteuthidae, lives in dim mid-water zones where sunlight barely reaches.
Important Note: Sources disagree on which species the name refers to, so it is best treated as a descriptive label for webbed-arm deep-sea squid rather than a precise species. Check the Latin name before relying on any care or range claim.
Squid in this group are built for darkness. They often have one large eye and one small one, rows of light-producing organs, and bodies that stay almost invisible from below. They are rarely seen alive, and most of what scientists know comes from nets, stomach contents, and remotely operated vehicles.
US researchers working off the Pacific and Atlantic coasts have photographed deep-water squid like these, and sperm whales feed on them heavily.
9. Umbrellabird
Umbrellabirds are crow-sized songbirds of Central and South American rainforests. Three species exist: the Amazonian umbrellabird (Cephalopterus ornatus), the long-wattled umbrellabird, and the bare-necked umbrellabird. All have a shaggy, domed crest of black feathers that falls forward over the bill like an umbrella.
The males also grow a fleshy, feather-covered wattle that hangs from the throat. In the long-wattled species, it can stretch longer than the bird’s own body. A-Z Animals describes them as having the booming voices of the rainforest canopy. Males use deep, low calls and a bowing display to attract females.
These birds depend on large tracts of intact forest, which makes them vulnerable to logging and farming. Birders from the US often make Costa Rica and Ecuador lodges their first stop to find one. For more bird names that fit alphabet-themed lists, try these bird names that start with K.
10. Unau
The unau is the Linnaeus’s two-toed sloth (Choloepus didactylus), a slow-moving mammal of northern South America. Despite the name, it has two long claws on each forelimb and three on each hind limb. It sleeps most of the day, moves through the treetops at night, and climbs down to the ground about once a week to defecate.
Its slow metabolism is the defining trait. Algae grow in its coarse fur, giving the coat a greenish cast that helps it blend into the canopy. A hanging unau can look like a clump of moss.
Sloths have a surprising link to American history. Thomas Jefferson described the claw of a giant ground sloth from a Virginia cave in 1797, and the animal, later named Megalonyx jeffersonii, helped launch vertebrate paleontology in the United States. For more mammals with a slow pace, the animals that start with S include several relatives.
11. Underwing Moth
Underwing moths belong to the genus Catocala, and North America has more than 100 species. A typical example is the Ilia underwing (Catocala ilia). By day, the forewings look like tree bark, which hides the moth against a trunk. When a bird gets too close, the moth flashes bright hindwings of orange, red, or yellow with black bands.
That sudden flash startles a predator for a second, and the moth is gone. The fast switch from camouflage to warning color is one of the better-known defenses among North American moths. Many of the species feed as caterpillars on oaks, willows, poplars, and hickories.
The group also has a long history among American collectors. Naturalists in the 1800s and early 1900s painted a sugary, fermented mixture on tree trunks at night to draw underwings in, a technique called sugaring. Hobbyists still use it today, and it is a good way to see moths up close in an eastern backyard.
12. Upland Sandpiper
The upland sandpiper (Bartramia longicauda) is a shorebird that lives nowhere near a shore. It nests in the open prairies and hayfields of the northern Great Plains and Midwest, then flies to South America’s pampas for the winter. Its genus honors William Bartram, the Philadelphia naturalist.
It is slender and long-necked, with a small head and large dark eyes. Look for a bird standing upright on a fence post, holding its wings up for a moment after landing. Its mournful, rolling whistle carries across grassland at dusk.
The upland sandpiper was once called the upland plover, and market hunters shot enormous numbers of them in the 1800s. Federal protection under the Migratory Bird Treaty Act helped the population recover somewhat, but grassland loss remains the main problem. Another good place to start is the list of bird names that start with I.
Pro Tip: Look for upland sandpipers on grassland airfields and in large hay meadows from late April through July, and scan fence posts first. They tend to perch where the view is widest.
13. Ural Owl
The Ural owl (Strix uralensis) is a large, round-headed owl with a long tail and pale gray-brown feathers. It lives in the taiga and mixed forests of northern Europe and Asia, including the Ural Mountains that give it its name. It is not a North American bird, so American birders usually have to travel to Finland, Sweden, or Russia to find one.
It is known for defending its nest. People who walk too close to a Ural owl’s nest cavity have been struck on the head by an adult, and wildlife photographers are warned to keep a distance. The owl hunts voles and other small mammals, and its numbers rise and fall with vole cycles.
Conservation groups reintroduced the species in parts of Central Europe where it had vanished. If you like owls, the animals that start with O cover several more.
14. Urial
The urial is a wild sheep of the rocky hills and open steppe of Central and South Asia. Cool Wood Wildlife Park describes it as a wild sheep found in Central and South Asia, with the scientific name Ovis orientalis vignei. Many biologists list it separately as Ovis vignei, so the classification varies by source. Males carry heavy, curling horns and a dark ruff of hair on the chest.
The urial lives in the same belt of Eurasia where people first domesticated sheep, goats, and cattle. Wild sheep are part of the story of how farming spread, and the urial is among the species whose relatives eventually became the domestic flock. The wider region is also central to Przewalski’s horse origins. A 2018 study in the journal Science found that today’s Przewalski’s horses descend from horses once kept by the Botai people of Kazakhstan. They are feral descendants of the earliest domesticated horse breeds, not purely wild animals.
For readers following that thread, the horse breeds that start with B offer a lighter way into horse history. Back to the urial: hunting and competition with livestock have reduced its range, and several populations are now protected.
15. Uromastyx
Uromastyx lizards, also called spiny-tailed lizards, are stocky desert reptiles from North Africa and the Middle East. A common species is the Egyptian spiny-tailed lizard (Uromastyx aegyptia). Each has a thick tail covered in rings of spiked scales, which it uses to plug its burrow entrance against predators.
Adults are mostly herbivores and eat seeds, leaves, and flowers. One list notes that adults eat mainly vegetation. They bask in extreme heat, and their color shifts from drab to bright as they warm up in the morning sun.
Uromastyx are a popular choice in the American reptile trade, especially at expos in Florida, Texas, and California. They need very hot basking spots, strong UVB lighting, and a dry diet. A beginner often underestimates the heat requirement, which is why the animal tends to appear on lists of species suited to experienced keepers.
16. Urutu Snake
The urutu (Bothrops alternatus) is a venomous pit viper of southern South America. It claims territories in Brazil, Paraguay, Uruguay, and Argentina, according to Trvst. Local names include cruzeira, which refers to the cross-shaped marking on its back.
Its coat is brown or gray with dark, paired blotches edged in a pale line. The pattern breaks up the snake’s outline on leaf litter and grass. It ambushes rodents in farmland and wet grassland, and bites can become serious because many occur near rural homes.
The urutu is not found in the wild in the United States. American readers meet it in zoo reptile houses, herpetology textbooks, and the lists of New World pit vipers that include rattlesnakes and copperheads. All of those share the heat-sensing pit between eye and nostril.
17. Utah Prairie Dog
The Utah prairie dog (Cynomys parvidens) is the best-documented animal on this list, and the most American. It is found only in southwestern and central Utah. It is also the only prairie dog species in the US listed as endangered or threatened under the Endangered Species Act. Its colonies sit in the high valleys of southern Utah, around Bryce Canyon and Cedar City.
Its decline had clear causes. Barbara Sugarman, a Utah Division of Wildlife Resources biologist, said unregulated poisoning and plague were the primary threats. Control programs and intensive poisoning reduced the species to a low of about 3,300 animals in the 1970s, according to WildEarth Guardians.
The legal history runs in short steps:
- The species was listed as endangered on June 4, 1973.
- On May 29, 1984, it was reclassified as threatened, with a special rule allowing regulated take.
- The US Fish and Wildlife Service released a final revised recovery plan in 2012. The notice was published in the Federal Register.
Recent counts are more hopeful. In a May 2024 report, TownLift quoted wildlife officials saying spring counts the year before had found just under 10,000 animals. The same report said long-term data suggest the population has been stable or increasing for three decades.
Key Insight: Roughly 70 percent of Utah prairie dogs live on private land, according to a Utah State University conservation page. That makes recovery a matter of negotiating with ranchers, farmers, and developers, not only managing federal land.
The animal matters beyond its own numbers. Predators such as kit foxes, golden eagles, and ferruginous hawks eat prairie dogs, and snakes, cottontails, and burrowing owls use their burrows.
18. Utonagan
The Utonagan is the only domestic dog on this list, and it is a modern invention. It was developed in the United Kingdom in the late 1980s by breeders who wanted a dog that looked like a wolf but carried no wolf blood. The foundation stock is generally described as Alaskan Malamutes, Siberian Huskies, and German Shepherds, all of which are Canis lupus familiaris.
Adults are large, thick-coated dogs with erect ears, amber or brown eyes, and a plume tail. The coat comes in gray, black, and sable shades. Breeders stress a gentle, social temperament, and the breed is described as friendly with family, though it is not suited to people who dislike barking, howling, and shedding.
The breed is rare in America, and the American Kennel Club does not recognize it. Buyers should be wary of anyone selling a “wolf-like” dog without health testing. For other breed names, the list of dog breeds that start with R is a good next stop.
That closes the roster of animals that start with U, a mix of an ancient fossil giant, a sloth with two claws, a threatened western rodent, and a recent designer dog. If you are working through the alphabet, the animals that start with V come next.