Ursus (genus) — large bears of the Northern Hemisphere Ursus (genus) Ursus is a genus of bears that includes brown, polar and several black bear species. This article summarizes their traits, species, evolution, ecology and relationships with people…
Utahraptor — large dromaeosaurid predator Utahraptor Utahraptor was a large, agile dromaeosaurid from the Early Cretaceous, notable for its oversized sickle-shaped toe claw, birdlike anatomy, and importance to studies of raptor evolu…
Utatsusaurus: an early ichthyopterygian from the Lower Triassic Utatsusaurus Utatsusaurus, a basal ichthyopterygian from the earliest Lower Triassic, is a slender, nearly 3 m marine reptile known from Japan and Canada. It shows transitional features between…
Valdosaurus: Early Cretaceous bipedal herbivorous dinosaur Valdosaurus Valdosaurus is a small bipedal herbivorous ornithopod from the Lower Cretaceous of southern England, placed in Dryosauridae and important for understanding early iguanodontian evol…
Valvatida: the diverse order of sea stars Valvatida Valvatida is an order of starfish (class Asteroidea) characterized by plated skeletons and diverse lifestyles; it includes many familiar reef species and is important in benthic ec…
Vampire bat Small New World bats that drink blood; three species feed on vertebrate blood and are noted for specialized anatomy, social behavior, medical interest and rabies transmission.
Vampire squid (Vampyroteuthis infernalis) Vampire squid A deep-sea cephalopod with a cloak-like web, retractile filaments and bioluminescence; uniquely adapted to low-oxygen waters and the only living member of its order.
Vampyromorphida — the vampire squid order of deep‑sea cephalopods Vampyromorphida Vampyromorphida is an order of cephalopods that includes one living species, Vampyroteuthis infernalis, and a number of extinct relatives known from the fossil record.
Vangunu giant rat (Uromys vika) Vangunu giant rat Uromys vika, the Vangunu giant rat or vika, is a large arboreal rodent from Vangunu Island (Solomon Islands), known from recent discovery and DNA-confirmed description; it faces ha…
Vaquita (Phocoena sinus): the critically endangered porpoise of the Gulf of California Vaquita The vaquita is the world’s smallest porpoise, endemic to the northern Gulf of California. Critically Endangered, it faces catastrophic decline from gillnet bycatch and illegal toto…
Varanidae: the monitor lizard family Varanidae Varanidae is the reptile family that contains monitor lizards (genus Varanus). Members are carnivorous, ecologically versatile predators found across Africa, Asia, and Australasia,…
Vegavis — a Cretaceous bird linking modern waterfowl to Mesozoic avifauna Vegavis Vegavis is an extinct genus of bird from the latest Cretaceous of Antarctica whose fossils indicate close relationships with modern ducks and geese and show Cretaceous diversificat…
Velafrons — a hadrosaurid dinosaur from Mexico Velafrons Velafrons is a genus of duck‑billed (hadrosaurid) dinosaur known from a distinctive sail‑like forehead. Its fossils come from the Upper Cretaceous Cerro del Pueblo Formation in Coa…
Velociraptor — Late Cretaceous dromaeosaurid (genus) Velociraptor Small feathered dromaeosaurid from the Late Cretaceous of Asia, noted for a recurved sickle claw, bird-like anatomy, and the famous 'Fighting Dinosaurs' fossil with Protoceratops.
Velocisaurus — a small cursorial theropod from Patagonia Velocisaurus Velocisaurus, known from leg and foot bones found in Patagonia, is a small Cretaceous theropod notable for an unusual weight-bearing third metatarsal and adaptations for running.
Velvet worms (Onychophora): biology, distribution and evolutionary importance Velvet worm Velvet worms (Onychophora) are soft-bodied terrestrial panarthropods with lobopod legs and slime-spraying glands. About 200 species inhabit moist tropical and southern temperate re…
Veneridae — the Venus clams: biology, distribution, and human uses Veneridae Veneridae, or Venus clams, are a globally distributed family of bivalve molluscs with over 500 species. This article summarizes their anatomy, habitats, taxonomy, ecological role,…
Venomous snake A snake that produces and injects venom to immobilize prey or deter threats; includes vipers, elapids and some colubrids. Important ecologically and medically; study informs antive…
Vervet monkey (Chlorocebus pygerythrus): appearance, behavior and distribution Vervet monkey The vervet is an Old World monkey native to sub-Saharan Africa, noted for its grey coat, black face, alarm-call communication, adaptable diet, social groups, and established introd…
Viceroy (butterfly) The Viceroy (Limenitis archippus) is a North American butterfly in the Nymphalidae family, known for its resemblance to the monarch, distinct black hindwing band, willow-feeding ca…
Vicuña: the wild Andean camelid and its wool Vicuña The vicuña (Vicugna vicugna) is a small wild South American camelid native to the high Andes, prized for its exceptionally fine wool and subject to conservation and sustainable-use…
Viper (family Viperidae) Viper Vipers are a family of venomous snakes (Viperidae) known for long, hinged fangs, hemotoxic venom, and diverse habits across Africa, Asia, Europe and the Americas.
Viperinae (Old World vipers) Viperinae Viperinae, or Old World vipers, are a subfamily of venomous snakes native to Europe, Asia and Africa. They include roughly a dozen genera and some 60–70 species notable for hinged…
Vireo (Vireonidae): small New World passerine birds Vireo Vireos are small, often greenish passerine birds of the New World. Shy and insectivorous, they build cup nests, sing distinctive songs, and recent DNA work links them to corvid rel…
Virginia opossum (Didelphis virginiana) Virginia opossum The Virginia opossum is the only marsupial native to North America. This nocturnal, adaptable omnivore is known for its pouch, prehensile tail, short lifespan, and its defensive "p…
Virus classification: systems, criteria, and why it matters Virus classification How scientists group viruses by genome, structure and replication. Overview of ICTV taxonomy, Baltimore groups, naming conventions, practical uses, and modern challenges in viral c…
Viscacha (Chinchillidae): species, appearance, behaviour and conservation Viscacha Viscachas are South American rodents in the family Chinchillidae. This article summarizes their classification, the four species, appearance, ecology, distribution from Pampas to h…
Viverravidae: extinct family of early carnivorous mammals Viverravidae Viverravidae were small to medium Paleocene–Eocene mammalian carnivores (Miacoidea) known for long skulls and reduced molars; their exact relationship to modern Carnivora remains d…
Viverridae: biology, distribution, and taxonomy of viverrids Viverridae Viverridae are small to medium cat-like carnivores in the Feliformia. This article explains their appearance, classification, range, ecology, and conservation issues.
Vodka (Japanese Thoroughbred racemare) Vodka (horse) Vodka (2004–2019) was a Japanese Thoroughbred racemare who won the 2007 Tokyo Yūshun (Japanese Derby) and seven G1 races. She later stood as a broodmare and died of laminitis in Ne…
Vogelkop bowerbird (Amblyornis inornata) Vogelkop bowerbird A medium-sized bowerbird from the Vogelkop Peninsula of Western New Guinea, known for elaborate male-built display courts adorned with natural objects to attract mates.
Volcano rabbit (teporingo): a small endangered rabbit of central Mexico Volcano rabbit The volcano rabbit (Romerolagus diazi), locally called teporingo or zacatuche, is a small, highland rabbit endemic to central Mexico, threatened by habitat loss and protected under…
Vole: Small Rodents of the Subfamily Arvicolinae Vole An overview of voles—their appearance, behavior, ecology, notable species, reproduction, and relationships with humans and predators.
Vulcanodon — an early sauropod from the Early Jurassic Vulcanodon Vulcanodon is an early long-necked sauropod known from partial remains in Zimbabwe. It shows primitive and derived features and helps illustrate the transition to giant, quadrupeda…
Vulture: ecology, biology, and cultural role Vulture Vultures are large carrion-eating birds found worldwide in two unrelated groups. This article explains their anatomy, behavior, classification, ecological importance, threats, and…
Wader (shorebird): overview, behaviour, feeding and conservation Wader Waders, commonly called shorebirds, are water-associated birds in the order Charadriiformes. This article describes their traits, feeding, migration, notable species and conservati…
Wagtail (Motacilla): small long-tailed insectivorous birds Wagtail Wagtails are slender, long-tailed passerines known for constant tail-wagging. They are insectivorous, often live near open ground or water, and include familiar species like the wh…
Wakinosaurus — dubious theropod genus from Japan Wakinosaurus Wakinosaurus is a genus named from a single serrated tooth found in Lower Cretaceous deposits of Fukuoka, Japan; it is generally regarded as a nomen dubium because isolated teeth a…
Wallaby — Small macropod species native to Australia and nearby islands Wallaby Wallabies are small- to medium-sized marsupials in the macropod family. Found mainly in Australia, Tasmania and New Guinea, they occupy diverse habitats and play key ecological and…
Wallaroo (Australian macropod) Wallaroo Wallaroos are medium-sized Australian macropods between kangaroos and wallabies in size; they inhabit rocky and open country and include several species with differing habits and c…
Walleye (Sander vitreus): an overview of the North American gamefish Walleye Walleye (Sander vitreus) is a freshwater perciform fish native to most of Canada and the northern United States, prized by anglers and important to fisheries management.
Walrus (Odobenus rosmarus) Walrus Large, social Arctic pinniped noted for long tusks, thick blubber, and vibrissae; lives on sea ice and coasts of the northern oceans and plays a role in Indigenous cultures and Arc…
Wannanosaurus: a tiny pachycephalosaur from the Upper Cretaceous Wannanosaurus Wannanosaurus was a very small ornithischian dinosaur from the Late Cretaceous of China, known from a single partial skeleton; likely herbivorous with possible insectivory and a fl…
Wapiti (Elk) — Cervus canadensis Wapiti Wapiti, commonly called elk, are large deer (Cervus canadensis) native to North America and parts of eastern Asia. This article covers appearance, behavior, range, human relevance…
War Emblem — American Thoroughbred racehorse War Emblem War Emblem (1999–2020) was an American Thoroughbred best known for winning the 2002 Kentucky Derby and Preakness Stakes; later stood at stud overseas and spent his final years at O…
Warble fly (Hypoderma) — parasitic bot flies of livestock Warble fly Large parasitic flies of the genus Hypoderma that produce subcutaneous larvae ('warbles') in cattle, horses and other mammals; cause animal welfare, hide and production impacts and…
Domestic warren (rabbitry) Warren (domestic) A domestic warren is a purpose-built enclosure for raising rabbits in captivity, used in animal husbandry for meat, fur, breeding, and research; it contrasts with free or wild warr…
Warthog (Phacochoerus africanus): an adaptable African pig Warthog Overview of the warthog, a hardy wild pig of sub‑Saharan Africa: appearance, behaviour, range, adaptations to heat and drought, reproduction, ecology and relationship with people.
