Animals

Horned grebe (Slavonian grebe) Horned grebe Small diving waterbird (Podiceps auritus) found across northern Eurasia and North America, recognizable by golden 'horns' in breeding plumage; breeds on freshwater lakes and winter…

Horned lizard (Phrynosoma): desert-adapted spiny reptiles Horned lizard Horned lizards (genus Phrynosoma) are stout, short-bodied lizards of arid North America, known for horns, camouflage, ant-based diets and unusual defenses such as blood-squirting i…

Hornet (true hornets and hornet-like vespines) Hornet Hornets are the largest social vespine wasps. This entry covers identification, distribution, life cycle, behavior, ecological role, interactions with people, and basic management…

Horse: biology, history, uses and care Horse An overview of the horse (Equus caballus), covering anatomy, behavior, domestication, uses, basic care and distinctions such as breeds, ponies and hybrids.

Horse fly (Tabanidae): description, behavior, and impact Horse fly Horse flies are stout blood-feeding flies (family Tabanidae). Females bite to obtain blood for egg development; males feed on nectar. They affect livestock, act as occasional polli…

Horse training: methods, history, and welfare considerations Horse training Overview of how horses are trained for riding, driving and sport, the common methods and stages, historical background, practical uses, and welfare controversies and alternatives.

Horseshoe bats (Rhinolophidae): biology, distribution, and human interactions Horseshoe bat A concise overview of horseshoe bats (family Rhinolophidae): their anatomy, echolocation, evolution, range, role in ecosystems, links to coronaviruses, human uses, and conservation…

Horseshoe crab Marine arthropods related to spiders, known for a hard carapace, long tail spine and blue blood used in medicine; found in coastal and estuarine habitats and important ecologically…

Hourglass dolphin (Lagenorhynchus cruciger) Hourglass dolphin Small black-and-white dolphin of the Southern Ocean with distinctive hourglass side patches. Lives in near-freezing Antarctic waters, travels in small groups, and remains relativel…

House centipede (Scutigera coleoptrata): appearance, behavior, and role in homes House centipede Overview of the house centipede: identification, anatomy, life cycle, behavior, distribution, interactions with humans, and common misconceptions.

House mouse (Mus musculus) House mouse The house mouse (Mus musculus) is a small rodent found worldwide. Closely associated with people, it has important roles in research, ecology, pest management and public health.

Housefly (Musca domestica) Housefly Overview of the common housefly, Musca domestica: appearance, life cycle, role in human environments, health risks, ecological role and practical control measures.

Hoverfly (Syrphidae) — biology, mimicry, and ecological roles Hoverfly Hoverflies (family Syrphidae) are flower-visiting flies known for hovering flight, wasp-like coloration, diverse larval diets, pollination, and use as biological control agents.

Howler monkey (Alouatta): loud, arboreal New World primates Howler monkey Howler monkeys (genus Alouatta) are large, primarily leaf-eating New World primates known for extremely loud vocalizations, prehensile tails, and a distribution from southern Mexic…

Humboldt penguin (Spheniscus humboldti) Humboldt penguin A medium-sized South American penguin found along the coasts of Peru and Chile. Adapted to temperate waters, it nests in burrows and guano deposits and faces declines from habitat…

Hummingbird Hummingbirds (family Trochilidae) are tiny New World birds known for hovering flight, rapid wingbeats and nectar feeding. They are important pollinators with many colorful, iridesc…

Humpback whale (Megaptera novaeangliae) Humpback whale Large baleen whale known for long pectoral fins, acrobatic breaches, complex songs and long migrations between high-latitude feeding and low-latitude breeding grounds.

Hungarian Vizsla — medium hunting and companion dog Hungarian Vizsla The Hungarian Vizsla is a medium-sized hunting breed from Hungary, known for its affectionate nature, energetic drive, short golden-rust coat, and versatility as a gun dog, sport d…

Hunting dog: roles, types, history and modern use Hunting dog An overview of hunting dogs: their roles, major types (hounds, terriers, cur types, gun dogs), history, working traits, training and contemporary uses including conservation and pe…

Hyacinth macaw (Anodorhynchus hyacinthinus) — biology, range and conservation Hyacinth macaw The hyacinth macaw is the largest flying parrot, native to central and eastern South America. This article covers its appearance, behaviour, diet, habitat, threats, conservation st…

Hyaena (Hyena) — the family Hyaenidae, bone-crushers of Africa and Asia Hyaena Medium-sized carnivores of the family Hyaenidae, notable for powerful jaws, varied diets, complex social behavior and a primarily African distribution with a few Asian populations.

Hyaenodontidae Extinct family of creodont mammals notable for blade-like shearing teeth; diverse Paleogene–Neogene predators distributed across Africa, Eurasia and North America.

Hybrid (biology, breeding and broader uses) Hybrid A hybrid is an organism or object produced by combining different species, varieties, strains, or systems. In biology it denotes crosses between species or varieties; the term also…

Hydra (animal) — freshwater cnidarian polyp Hydra (animal) Hydra are small freshwater cnidarians: radially symmetric, two-layered polyps with stinging tentacles, notable for budding, regeneration, and use in ecological and developmental re…

Hydrozoa: biology, life cycles, diversity and ecological role Hydrozoa Hydrozoa are a class of mostly marine cnidarians including solitary and colonial forms. They show varied life cycles (polyp and medusa stages), include Hydra and siphonophores, and…

Hylarana tytleri — Theobald's (yellow-striped) ranid frog Hylarana tytleri A ranid frog species of South Asia (India, Bangladesh, Nepal, possibly Bhutan). Overview of appearance, habitat, behavior, taxonomy and conservation considerations.

Hylidae: the tree frog family Hylidae Hylidae is a diverse family of frogs commonly called tree frogs. Members range from arboreal climbers to ground- and water-associated species; they play important ecological roles…

Hylobates — genus of gibbons Hylobates Hylobates is a genus of small arboreal apes native to Southeast Asia, notable for brachiation, loud duets, a white facial ring in many species, 44 chromosomes, and several threaten…

Hylonomus — an early amniote from the Pennsylvanian of Nova Scotia Hylonomus Hylonomus is a small, lizard‑like early amniote from about 312 million years ago, known from fossils in Joggins, Nova Scotia. Its remains illuminate early terrestrial vertebrate ev…

Hymenoptera: wasps, bees, ants and sawflies Hymenoptera Hymenoptera is a diverse insect order including wasps, bees, ants and sawflies; notable for two pairs of membranous wings, a range of life histories from solitary to highly social,…

Hypacrosaurus — hollow-crested duck-billed dinosaur of the Late Cretaceous Hypacrosaurus Hypacrosaurus is a lambeosaurine hadrosaur known for its hollow cranial crest, dental batteries, and well-preserved nests and hatchlings from the Late Cretaceous of western North A…

Hyperoliidae — African reed and sedge frogs Hyperoliidae Hyperoliidae is a family of small to medium, often brightly colored frogs native mainly to sub‑Saharan Africa and nearby islands, with about 250 species in roughly 19 genera.

Hypselospinus — an Early Cretaceous iguanodontian dinosaur Hypselospinus Hypselospinus is an iguanodontian ornithopod from the Early Cretaceous Wealden of southern England, originally named as Iguanodon fittoni and later recognized as a distinct, gracil…

Hypsilophodon: a small, fast-running Early Cretaceous ornithopod Hypsilophodon Hypsilophodon was a small bipedal herbivorous dinosaur from the Early Cretaceous of Europe, notable for its speed, numerous fossils, and historical role in understanding small orni…

Hyracotherium — an early Eocene mammal linked to early perissodactyl evolution Hyracotherium Small, early Eocene mammal once conflated with the 'dawn horse'. Hyracotherium is a Eurasian palaeothere whose classification has been revised; it illuminates early hoofed mammal e…

Hyrax (dassie): small Afro‑Asian herbivores of the order Hyracoidea Hyrax Hyraxes (also called dassies) are compact, herbivorous mammals native to Africa and parts of southwestern Asia, notable for their unique anatomy and evolutionary relationship to el…

Iberian lynx (Lynx pardinus) Iberian lynx A small wild cat endemic to the Iberian Peninsula, the Iberian lynx is a rabbit-specialist felid that was once critically endangered and has been the focus of intensive conservatio…

Ibis — long‑billed wading birds of the family Threskiornithidae Ibis Ibis: long‑legged, down‑curved billed wading birds found worldwide in wetlands; social foragers, colonial nesters, and culturally significant in ancient societies.

Ichthyophiidae — Asiatic tailed caecilians Ichthyophiidae Ichthyophiidae: a family of primitive, egg-laying, burrowing caecilians of South and Southeast Asia, with a distinct tail, external larval stage and dermal scales; Ichthyophis is t…

Ichthyophis beddomei (Beddome's caecilian) Ichthyophis beddomei A limbless, burrowing amphibian of the Western Ghats with dark violet-brown skin and yellow lateral stripes. Member of the family Ichthyophiidae; important for soil ecology and amp…

Ichthyornis: a toothed seabird of the Late Cretaceous Ichthyornis Ichthyornis, a seabird-like avian from the Upper Cretaceous, combined modern flight anatomy with primitive teeth and hunted fish in the Western Interior Seaway of ancient North Ame…

Ichthyosaur (extinct Mesozoic marine reptile) Ichthyosaur Ichthyosaurs were dolphin-like marine reptiles of the Mesozoic, with streamlined bodies, large eyes and live birth. Their global fossils illustrate marine adaptation and convergent…

Ichthyosaurus — Early Jurassic marine reptile genus Ichthyosaurus Ichthyosaurus, an Early Jurassic ichthyosaur first recognized from Mary Anning’s finds, is a dolphin‑like marine reptile known from many European fossils and important to understan…

Ichthyovenator: Early Cretaceous Asian spinosaurid with a split dorsal sail Ichthyovenator Ichthyovenator, an Early Cretaceous spinosaurid from Laos (125–113 Ma), known for crocodile-like, fish‑grasping jaws and a distinctive split dorsal sail over the hips formed by elo…

Icterids: New World blackbirds, orioles and their relatives Icterid Icteridae are a diverse family of New World songbirds including blackbirds, orioles, grackles, cowbirds and oropendolas, notable for bright plumage, sexual dimorphism and a unique…

Iguana (genus Iguana) Iguana Iguanas are large tropical lizards of the genus Iguana, native to the Americas and Caribbean. This article outlines their appearance, ecology, behavior, human interactions, and con…

Iguanodon: Early Cretaceous Ornithopod Dinosaur Iguanodon Iguanodon is a genus of large herbivorous ornithopod from the Early Cretaceous, famous for its early discovery, distinctive thumb spike and complex taxonomic history.

Iguanodonts: herbivorous ornithopods and their place in dinosaur classification Iguanodont Iguanodonts are a group of herbivorous ornithopod dinosaurs that include Iguanodon-like forms and their relatives. Their anatomy, fossil history, and debated classification link th…