Animals

Dewlap: the throat fold in animals and its functions Dewlap A dewlap is a hanging fold of skin or fleshy protuberance beneath the throat found in many animals. It serves roles in display, thermoregulation, nesting, and species recognition a…

Dhole (Cuon alpinus) — the Asiatic wild dog Dhole The dhole is a social, diurnal canid native to parts of Asia. This article covers its identity, behaviour, historic range, ecological role, and the threats that have made it an end…

Diamantinasaurus — a titanosaurian sauropod from Early Cretaceous Australia Diamantinasaurus Diamantinasaurus is a genus of derived titanosaurian sauropod known from Early Cretaceous rocks in Australia. Partial skeletons illuminate its anatomy and the evolution of Gondwana…

Diamondback rattlesnake A broad overview of the diamondback rattlesnake: identification, distribution, behavior, venom effects, human safety, and conservation of eastern and western species.

Diapsid: reptiles with two temporal skull openings Diapsid Diapsids are a major group of amniotes whose skulls have two temporal fenestrae per side; they include most living reptiles, birds (from dinosaurs), and many fossil lineages.

Dice snake (Natrix tessellata) Dice snake A non-venomous, mostly aquatic colubrid found across parts of Europe and western Asia, the dice snake hunts fish and amphibians, is an adept swimmer, and shows seasonal hibernation…

Dicraeosaurus Dicraeosaurus is a relatively small dicraeosaurid sauropod from the Late Jurassic Tendaguru beds of Tanzania, notable for short necks, elongated neural spines, and evidence of feed…

Dictyoptera: cockroaches, termites and mantids — characteristics and classification Dictyoptera Dictyoptera is an insect group that unites cockroaches, termites and mantids. This article explains their defining traits, fossil history, taxonomy, ecological roles and relationsh…

Dicynodonts — two‑tusked herbivorous therapsids Dicynodont Dicynodonts (Dicynodontia) were diverse, mainly herbivorous therapsids with a beak and two tusks. Widespread from the Permian into the Triassic, they played major ecological roles…

Didelphis — genus of large American opossums Didelphis Didelphis is a genus of medium-to-large New World marsupials known as opossums. Members are omnivorous, nocturnal, and ecologically important scavengers found across the Americas.

Didynamipus — the four‑digit toad, a monotypic genus of Bufonidae Didynamipus Didynamipus is a small, monotypic genus of true toads (Bufonidae) containing Didynamipus sjostedti, the four‑digit toad, native to parts of West and Central Africa and threatened b…

Digenea — digenetic trematodes (parasitic flukes) Digenea Digenea are a group of parasitic flatworms (flukes) with complex life cycles that typically involve molluscan intermediate hosts and vertebrate definitive hosts.

Dik-dik: small African antelopes of the genus Madoqua Dik-dik Dik-diks are tiny, territorial antelopes from eastern and southern Africa. This article covers their appearance, behavior, habitat, predators, species, and interactions with people…

Dilong paradoxus — small feathered tyrannosauroid from Early Cretaceous China Dilong paradoxus Dilong paradoxus is a small, feathered tyrannosauroid from the Lower Cretaceous of Liaoning, China. Its fossils show protofeathers and have shaped ideas about the evolution of feat…

Dilophosaurus — an Early Jurassic crested theropod Dilophosaurus Medium-sized Early Jurassic theropod notable for paired cranial crests. Known from the American Southwest, Dilophosaurus helps explain early large carnivore evolution and is often…

Dimetrodon — sail-backed Permian synapsid Dimetrodon Dimetrodon, a sail-backed synapsid from the Early–Middle Permian, was a dominant terrestrial predator known for its elongated neural spines and likely thermoregulatory and display…

Dimorphodon — Early Jurassic pterosaur notable for two tooth types Dimorphodon Dimorphodon is an Early Jurassic pterosaur known for a large head, heterodont dentition (two tooth types), and early fossil discoveries in England by Mary Anning; it illuminates pt…

Dingo: wild canid of Australia and Southeast Asia Dingo Overview of the dingo (Canis lupus dingo): appearance, distribution, origins, behaviour, relationships with people, taxonomy, conservation and management issues.

Dinornis — the giant moa of New Zealand Dinornis Dinornis is an extinct genus of giant, flightless moa endemic to New Zealand. This article summarizes its appearance, species, discovery, extinction, and scientific significance.

Dinosaurs: biology, evolution, fossils and cultural significance Dinosaur Dinosaurs were a diverse clade of archosaur reptiles that dominated terrestrial ecosystems in the Mesozoic. This article covers origins, anatomy, fossil history, the rise of birds…

Dinosaur brains and intelligence Summary of what scientists know about dinosaur brains, how they are studied, examples of relatively large-brained species, and common misconceptions about their intelligence.

Diplodocids (Diplodocidae): long-necked sauropod dinosaurs Diplodocid Diplodocids are a family of large, long-necked sauropod dinosaurs known for extreme body length, peg-like teeth and distinctive tail anatomy. Notable members include Diplodocus, Ap…

Diplodocus: long-necked Late Jurassic sauropod Diplodocus Diplodocus was a long, slender sauropod of the Late Jurassic, noted for its extremely long neck and tail, peg-like teeth for stripping vegetation, and its prominence in museum disp…

Diploglossus: a genus of New World anguids Diploglossus Diploglossus is a genus of anguids (galliwasps) native to the Americas. Species are secretive, ground-dwelling lizards with elongated bodies; taxonomy and conservation status vary…

Dipodidae: jerboas, jumping mice and birch mice Dipodidae Dipodidae is a family of small to medium bipedal rodents of the Northern Hemisphere, including jerboas, jumping mice and birch mice, adapted for saltatory locomotion in deserts, gr…

Diprotodon: Largest Pleistocene Marsupial of Australia Diprotodon Diprotodon, Australia's largest Pleistocene marsupial, resembled a hornless rhino/hippo: massive, furred, and possibly water-associated. Explore its fossils, size, ecology, and the…

Diprotodontia: The Australasian marsupial order Diprotodont Diprotodontia is a diverse order of Australasian marsupials—about 120 species including kangaroos, wallabies, possums, koala and wombats—defined by forward lower incisors and synda…

Dire wolf (Canis dirus): Prehistoric predator of the Americas Dire wolf Extinct large canid of the Late Pleistocene and early Holocene Americas. Known from abundant fossil sites, robust jaws and teeth, probable pack behavior, and extinction during late…

Discoglossidae — disc‑tongued frogs: overview, genera, distribution and biology Discoglossidae A concise encyclopedia entry on Discoglossidae, the traditional group of disc‑tongued frogs: their defining features, genera (Alytes and Discoglossus), distribution, life cycle, an…

Diurnal: daytime activity patterns in animals and plants Diurnal Diurnal describes organisms active during daylight hours. This article explains biological rhythms, adaptations, examples across groups, distinctions from nocturnal/crepuscular pat…

Dobermann (Doberman Pinscher) — Breed overview and history Dobermann Profile of the Dobermann (Doberman Pinscher): origin, physical and behavioral traits, common roles, health and care, and notable distinctions about cropping, training, and temperam…

Dodo (Raphus cucullatus): flightless bird of Mauritius and emblem of extinction Dodo The dodo, Raphus cucullatus, was a large flightless bird native to Mauritius. Extinct by the late 17th century, it is notable for its biology, rapid disappearance after human conta…

Dog (Canis lupus familiaris): domestication, traits, roles, and care Dog An authoritative overview of the domestic dog: origins, anatomy and behaviour, common roles, care and nutrition, breeds and notable facts, with distinctions from wild canids.

Dogue de Bordeaux (French Mastiff) — characteristics, history and care Dogue de Bordeaux Large French mastiff breed noted for its massive head, muscular build and calm loyalty. Overview of appearance, temperament, history, health concerns and practical care.

Dolly (sheep): first mammal cloned from an adult somatic cell Dolly (sheep) Dolly (1996–2003) was the first mammal cloned from an adult somatic cell. Her birth advanced developmental biology, raised ethical debate, and influenced cloning and stem‑cell rese…

Dolly Varden (Salvelinus malma) Dolly Varden A comprehensive overview of the Dolly Varden char: appearance, life cycle, distribution across the North Pacific, taxonomy issues, human uses, and conservation considerations.

Dolphin (Delphinidae and relatives): biology, behavior, and conservation Dolphin Overview of dolphins: anatomy, behavior, taxonomy (oceanic and river species), intelligence and echolocation, human interactions, and conservation challenges.

Domestic goat (Capra hircus) Domestic goat Overview of the domestic goat, its appearance, behavior, history of domestication, common uses (milk, meat, fiber), husbandry, and notable biological traits.

Domestic sheep (Ovis aries): overview, traits, uses and management Domestic sheep Domestic sheep (Ovis aries) are a globally kept ruminant raised for wool, meat and milk. This article covers their biology, history of domestication, common uses, breed types and b…

Domestic yak (Bos grunniens): overview, traits, uses, and origins Domestic yak The domestic yak (Bos grunniens) is a long-haired bovid adapted to high plateaus of Central and South Asia. This article covers appearance, adaptations, history, husbandry, and dis…

Dominance (ethology) Dominance in ethology describes repeated asymmetrical relationships in which one animal gains priority access to resources and influences interactions with conspecifics.

Donkey (Equus africanus asinus): description, history, uses, and hybrids Donkey Donkey (Equus africanus asinus): a domestic equid used for transport and work. Overview of appearance, behavior, domestication, human uses, hybrids with horses, breeds, and conserv…

Donkey Kong: Nintendo's Gorilla Icon Donkey Kong Donkey Kong is a long-running Nintendo video game character — a large gorilla who has appeared as both antagonist and hero since 1981, known for his red tie and starring role in pl…

Dormouse (Gliridae): small hibernating rodents Dormouse Small, mostly arboreal rodents of the family Gliridae, native chiefly to Europe with species in Africa and Asia. Noted for long hibernation, nocturnal habits, and conservation inte…

Dove: natural history, biology, and relationship with humans Dove Doves and pigeons (family Columbidae) are stout-bodied birds known for seed-based diets, unique crop milk, wide distribution, domestication history, cultural symbolism, and varying…

Draco (genus) — the gliding 'flying' dragons of Southeast Asia Draco (genus) Draco is a genus of small agamid lizards that glide between trees using extendable rib-supported membranes. Found in Asian forests, they feed on insects, lay eggs in soil, and incl…

Dracorex — a Late Cretaceous pachycephalosaur and its debated identity Dracorex Dracorex is a pachycephalosaur known from a distinctive skull found in the Hell Creek Formation. Its classification and name (referencing Hogwarts) have been the subject of scienti…

Dracovenator — Early Jurassic carnivorous dinosaur from southern Africa Dracovenator Dracovenator regenti, a large Early Jurassic theropod from the Elliot Formation of South Africa; known from fragmentary remains and notable as an early large meat‑eater related to…