Anatidae: the ducks, geese and swans (waterfowl family) Anatidae Anatidae is the family of water-adapted birds that includes ducks, geese and swans. Widespread and diverse, they are adapted for swimming, floating and sometimes diving, and have i…
Anatinae — the dabbling ducks subfamily Anatinae Anatinae is the subfamily of Anatidae that comprises the dabbling ducks and close relatives, characterized by surface-feeding behavior, broad bills with lamellae, and a global fres…
Anchiceratops — horned ceratopsian from the Late Cretaceous Anchiceratops Anchiceratops, a chasmosaurine ceratopsid from Alberta's Horseshoe Canyon Formation, is a three-horned, frilled herbivore known from a single species, A. ornatus.
Anchiornis — small feathered dinosaur from the Late Jurassic Anchiornis Anchiornis is a tiny, feathered paravian from Late Jurassic Liaoning, China. Known from well-preserved fossils, it sheds light on early feather evolution, coloration, and the origi…
Anchisaurus — an early sauropodomorph dinosaur Anchisaurus Anchisaurus is a small Early Jurassic basal sauropodomorph from northeastern North America, known from fragmentary remains and important for understanding the origin of later sauro…
Anchovy (Engraulidae): biology, uses, and ecological role Anchovy Small schooling saltwater fish of the family Engraulidae; plankton feeders that play a key role in marine food webs and human cuisine, and are important in fisheries worldwide.
Andean condor (Vultur gryphus): description, behavior, and conservation Andean condor Large South American vulture of the high Andes. A soaring scavenger with the Western Hemisphere's largest wingspan; culturally important and of conservation concern due to habitat…
Andinophryne — a small Andean genus of true toads Andinophryne Andinophryne is a small genus of true toads with three species native to high-elevation Andean habitats, notable for specialized montane ecology and conservation concerns.
Andrewsarchus — a large Eocene mesonychid Andrewsarchus Andrewsarchus, known from a large skull found in Mongolia, was a big Eocene mesonychid. Its ecology, size and habits are debated because fossils are fragmentary; it is famous as a…
Andy Panda — Walter Lantz cartoon character Andy Panda Andy Panda is a Walter Lantz creation for Universal in the late 1930s and 1940s. A young, anthropomorphic panda who starred in theatrical shorts, introduced Woody Woodpecker, and a…
Angelshark (Squatina): morphology, behavior, habitat and conservation Angelshark Angelsharks are flattened, ambush‑predator sharks in the genus Squatina. Found in temperate and tropical seas, many species are rare or threatened and have distinctive adaptations…
Anglerfish (order Lophiiformes) Anglerfish Predatory marine fishes known for a rod-like bioluminescent lure used to attract prey; diverse forms live from shallow reefs to the deep sea and show extreme sexual dimorphism in s…
Angloposeidon: large Early Cretaceous sauropod from the Isle of Wight Angloposeidon Angloposeidon is an informal name for a very large sauropod known from fragmentary remains found on the Isle of Wight; important for studies of Early Cretaceous European dinosaur f…
Angola colobus (Colobus angolensis) Angola colobus A black-and-white, leaf-eating Old World monkey of the genus Colobus. Arboreal and distinctive for reduced thumbs, a long tail, and a foregut adapted for digesting foliage; regiona…
Angolan African Dormouse (Graphiurus angolensis) Angolan African dormouse A small, nocturnal rodent of the family Gliridae, the Angolan African dormouse is found only in Angola and associated with subtropical or tropical dry forest habitats.
Anguidae — the anguid lizards (glass lizards, alligator lizards, slowworms) Anguidae Anguidae is a family of mostly elongate lizards including glass lizards, alligator lizards and slowworms, notable for limb reduction, tail autotomy and a wide Holarctic and Neotrop…
Anguis — slowworms (legless lizards) Anguis Anguis is a genus of legless lizards called slowworms or blindworms, native to Europe and western Asia. They resemble snakes but retain lizard traits such as eyelids, ear openings…
Anguis fragilis (slow-worm): biology, identification, distribution and conservation Anguis fragilis Encyclopedic overview of the slow-worm (Anguis fragilis): appearance, behaviour, range, reproduction, ecology, how to distinguish it from snakes, and conservation issues.
Angus cattle (Black Angus / Aberdeen Angus) Angus cattle Angus cattle, commonly called Black Angus or Aberdeen Angus, are a Scottish breed of naturally polled beef cattle valued for meat quality, adaptability, and global popularity.
Anhanguera — tooth‑crested pterosaur from the Cretaceous Anhanguera Anhanguera is a genus of toothed pterosaurs from the Early Cretaceous Santana Formation of Brazil, known for its long skull, snout crest and piscivorous lifestyle; several species…
Animal (Metazoa): overview, characteristics, evolution and ecological roles Animal Concise encyclopedia entry on animals (Metazoa): defining traits, body plans, evolution, ecology, classification, and differences from plants and fungi.
Animal husbandry: care, breeding and management of domesticated animals Animal husbandry Comprehensive overview of animal husbandry: its practices, history, common systems (dairy, beef, swine, sheep, poultry, apiculture), and key issues in modern management.
Animal Jam: an overview of the children's virtual world Animal Jam Animal Jam is a popular online virtual world for children created by WildWorks with the National Geographic Society, combining social play, customization, and age-appropriate educa…
Animal trapping: methods, history, uses, and welfare concerns Animal trapping Overview of animal trapping: devices and methods, reasons for use, animal welfare and regulatory responses, notable trap types, and alternatives to lethal capture.
Animals (1977 album by Pink Floyd) Animals (Pink Floyd album) Animals is a 1977 concept album by Pink Floyd, centred on social and political allegory. Known for its long tracks, stark cover art and Roger Waters' lyrical control, it remains a…
Animals of New Zealand: Evolution, Endemics, and Ecological Role Animals of New Zealand An overview of New Zealand’s animals, their Gondwanan origins, distinctive bird-dominated fauna, introduced species and conservation challenges.
Ankylopollexia — the thumb‑spiked ornithopod dinosaurs Ankylopollexia Ankylopollexia is a clade of herbivorous ornithischian dinosaurs that lived from the Late Jurassic to the end of the Cretaceous, including Iguanodon and the duck‑billed hadrosaurs.
Ankylosauria: the armored, herbivorous dinosaurs with bony plates and tail clubs Ankylosauria Ankylosauria were heavily armored, quadrupedal herbivorous dinosaurs of Ornithischia. Known for osteoderms, tail clubs (in some), and worldwide fossil distribution from the Middle…
Ankylosauridae — armored, tail‑club dinosaurs of the Cretaceous Ankylosauridae Ankylosauridae is a family of heavily armored, quadrupedal herbivorous dinosaurs noted for osteoderms and, in many genera, a bony tail club; they lived across Laurasia and disappea…
Ankylosaurus: the heavily armored, club-tailed herbivore of the Late Cretaceous Ankylosaurus Ankylosaurus magniventris was a large, low-slung armored dinosaur from Late Cretaceous North America, known for heavy osteoderm armor and a distinctive tail club used for defense.
Anna's hummingbird: appearance, behavior, range, and relationship with people Anna's hummingbird Anna's hummingbird (Calypte anna) is a small iridescent hummingbird of western North America, noted for the male's rose-red crown and throat, urban adaptability, year-round residen…
Anomalocaris: a Cambrian apex predator Anomalocaris Anomalocaris, an extinct radiodont often called an 'abnormal shrimp', was a large Cambrian predator with distinctive frontal appendages, a circular oral cone, and large compound ey…
Anopheles: mosquitoes, malaria vectors, and public health significance Anopheles Anopheles is a genus of mosquitoes that includes primary vectors of human malaria and other pathogens. This article summarizes their biology, diversity, role in disease transmissio…
Anseriformes: waterfowl, screamers and related birds Anseriformes Anseriformes are an order of about 150 species of primarily aquatic birds — ducks, geese, swans, screamers and the magpie goose — known for webbed feet, flattened bills and strong…
Ansonia (stream toads) Ansonia (frog) Ansonia is a genus of small, forest-dwelling true toads found across South and Southeast Asia, notable for their stream-breeding life cycle and torrent-adapted tadpoles.
Ant (Formicidae): biology, behavior, and ecological role Ant Ants are social insects of the family Formicidae. This article summarizes their anatomy, colony structure, behavior, evolution, ecological importance and distinctions from related…
Antarctic krill (Euphausia superba): biology, ecology, and human relevance Antarctic krill Antarctic krill (Euphausia superba) are shrimp-like crustaceans that form vast swarms in the Southern Ocean, fuel Antarctic food webs, and are subject to scientific study and comme…
Antbirds (Thamnophilidae): Neotropical insectivores and army-ant followers Antbird Antbirds (Thamnophilidae) are a diverse Neotropical family of over 200 small insectivorous passerines; many follow army ants, form long-term pairs, and are vulnerable to habitat lo…
Anteater (Vermilingua) Anteater Anteaters are insect-eating mammals of the suborder Vermilingua found in Central and South America, notable for long snouts, sticky tongues, powerful claws and specialized feeding…
Antelope: overview, characteristics, distribution, and relationship with humans Antelope Antelope is a common name for many even-toed bovids, primarily African and Asian, known for their horns, grazing habits, migrations, and varied adaptations across grassland, woodla…
Antiarchi — armored placoderm fishes of the Devonian Antiarchi Antiarchi (antiarchs) were a diverse order of armored placoderm fishes with bony anterior shields and jointed pectoral appendages; they were widespread in Devonian freshwater and n…
Antilopine kangaroo (Macropus antilopinus) Antilopine kangaroo A large grazing macropod of tropical northern Australia, the antilopine kangaroo shows strong sexual dimorphism, lives in social grazing groups, and faces regional threats from hab…
Antlers: structure, growth cycle, functions and distinctions Antlers Antlers are branched bony outgrowths found mainly on male deer. This article explains their composition, seasonal growth, roles in behaviour and reproduction, differences from horn…
Antlion (Myrmeleontidae): Natural History, Behavior, and Identification Antlion Antlions (family Myrmeleontidae) are neuropteran insects known for predatory larvae that often dig conical sand pits to trap prey. Adults resemble damselflies and have net-veined w…
Anura: frogs and toads — biology, diversity, and conservation Anura Anura is the amphibian order of frogs and toads. This article explains their anatomy, life cycle, diversity, evolution, ecological roles, human interactions, and conservation chall…
Anurognathus — small insectivorous pterosaur of the Late Jurassic Anurognathus Anurognathus, a tiny short‑skulled pterosaur from the Solnhofen limestones, was an agile aerial insectivore. This article summarizes its anatomy, fossils, paleobiology, and scienti…
Anzu wyliei: North American oviraptorosaur Anzu wyliei Anzu wyliei is a large, birdlike oviraptorosaur from the latest Cretaceous of the Dakotas. Known from multiple partial skeletons, it had a toothless beak, a thin cranial crest, lon…
Apatosaurus — Large sauropod of the Late Jurassic Apatosaurus Apatosaurus, a long-necked sauropod from the Late Jurassic, is known for its immense size, robust build, and a complicated taxonomic history that once involved Brontosaurus.
