The animal kingdom is vast and diverse, with many unique creatures. This article explores some of the lesser-known animals whose names begin with the letter ‘U’.
Mammals of the ‘U’ Realm
The Urial (Ovis orientalis vignei) is a wild sheep species characterized by its reddish-brown coat, which lightens during winter. Males possess impressive, large horns that curl outwards and backward, often reaching up to 3.3 feet in length. These herbivores primarily graze on grasses, shrubs, and leaves, inhabiting the mountainous and hilly regions of western Central Asia. Urials are considered vulnerable, facing threats from habitat loss and competition with livestock.
The Uakari (Cacajao) is a New World monkey distinguished by its bald head and a bright red face, indicating good health. Its body is covered in long, shaggy fur, and it has an unusually short tail. Uakaris reside in the flooded rainforests of the Amazon, primarily in Brazil and Peru, where they move through the trees using their strong limbs. These social primates gather in groups and primarily consume fruits and seeds, with some insects.
The Unau, also known as Linnaeus’s two-toed sloth (Choloepus didactylus), is one of the world’s slowest mammals. Its fur, often greenish from symbiotic algae, grows from its stomach to its back, shedding rainwater easily. Found in the tropical and subtropical rainforests of South America, this nocturnal and arboreal animal spends most of its life hanging upside down in trees. Unaus have a very slow metabolism, leading them to sleep for 15 to 20 hours daily and descend to the ground only about once a week.
Avian Wonders: ‘U’ Birds
The Umbrellabird (Cephalopterus) is a large, tropical bird named for its distinctive, umbrella-like head crest. These birds are almost entirely black and possess an inflatable wattle on their necks, amplifying their loud, booming calls. Found in the rainforests of Central and South America, Umbrellabirds primarily feed on fruits and large insects, aiding seed dispersal. Despite their size, they are clumsy flyers, often hopping between branches.
The Ural Owl (Strix uralensis) is a large nocturnal bird of prey with a rounded head and no ear tufts. Its plumage is pale grayish-brown to whitish, with a darker back. These owls inhabit the taiga forests across northern Eurasia, including the Ural Mountains, from which they get their name. Ural Owls are monogamous, often nesting in tree hollows, and hunt small mammals, birds, and insects, relying on exceptional hearing.
The Upland Sandpiper (Bartramia longicauda) is a shorebird that prefers open grasslands and prairies over coastal habitats. It has a small, dove-like head, long yellow legs, and a long tail. These migratory birds breed from eastern Alaska to the northeastern U.S. and Canada, wintering in South America. Upland Sandpipers primarily forage for insects like grasshoppers and crickets, often perching on fence posts or telephone poles.
Aquatic and Diverse ‘U’ Creatures
Sea Urchins (Echinoidea) are marine invertebrates with globular bodies covered in rigid, movable spines. They have a hard outer shell (test) made of calcium carbonate, and move slowly using hundreds of tiny tube feet. Found in every ocean and climate, from shallow shores to deep-sea environments, sea urchins are primarily herbivores, grazing on algae, but can also consume invertebrates. Their anatomy includes a mouth on their underside called “Aristotle’s Lantern.”
Fiddler Crabs (Uca) are semi-terrestrial crabs known for the male’s greatly enlarged claw, used in courtship displays. Their bodies are square-shaped, inhabiting sandy beaches and salt marshes in tropical and subtropical regions worldwide. Fiddler crabs construct burrows for shelter and mating, feeding by sifting through sediment for detritus, algae, and bacteria.
Unicornfish (Naso) are marine fish in the surgeonfish family, named for the horn-like protrusion that develops on the forehead, especially in mature males. They are found in shallow coral reefs across the Indo-Pacific. Unicornfish are herbivores, grazing on algae, and are generally calm, using sharp spines near their tails for defense rather than their “horn.”