Sea bass — common name for several marine and estuarine fishes Sea bass Sea bass is a non‑scientific name applied to multiple unrelated fish species found worldwide. This article explains common species, identification, culinary uses, fisheries and con…
Sea Cucumber: biology, ecology, uses and conservation Sea cucumber Comprehensive overview of sea cucumbers (Holothuroidea): anatomy, feeding, reproduction, ecological roles, human uses, fisheries, aquaculture and conservation challenges.
Sea devil Common name for several marine animals—especially devil rays (Mobulidae) and deep‑sea anglerfish—and used for ships, fiction, and nicknames; evokes a striking or fearsome appearanc…
Sea eagle (Haliaeetus): overview, appearance, behavior and conservation Sea eagle Sea eagles are large fish-eating raptors of the genus Haliaeetus, commonly called ernes. This article covers their appearance, habitat, diet, life history, notable species and cons…
Sea lion — eared marine mammals of the Otariidae family Sea lion Sea lions are gregarious marine mammals in the Otariidae (eared seals). They are adapted for swimming and land movement, feed on fish and squid, and form crowded breeding colonies…
Sea otter (Enhydra lutris): appearance, behavior, and conservation Sea otter A concise overview of the sea otter: its physical traits, diet and tool use, historic range and decline, ecological role as a kelp-forest keystone species, and modern recovery effo…
Sea slug: overview, groups, adaptations, and ecological role Sea slug Sea slug is an informal name for several marine gastropods with similar body plans (often shell‑reduced) that evolved independently. Includes nudibranchs, sacoglossans, sea hares a…
Sea snail — marine gastropod overview, biology, and significance Sea snail Sea snail is the common name for marine gastropod mollusks: diverse, usually shelled animals found from shorelines to the deep sea with varied diets, life histories, cultural uses…
Sea snake (marine elapid) Sea snake Sea snakes are venomous elapid snakes largely adapted to life in warm coastal and reef waters of the Indian and Pacific Oceans, with specialised anatomy, behaviour, and conservatio…
Sea spider (Pycnogonida) Sea spider Sea spiders are marine arthropods of the class Pycnogonida, with long legs and small bodies. Found worldwide from coasts to deep sea, they have unusual anatomy, male parental care…
Sea turtle (Chelonioidea): biology, species, and conservation Sea turtle Sea turtles are marine reptiles of the superfamily Chelonioidea. This article summarizes their biology, the seven living species, evolutionary history, lifecycle, threats, and cons…
Sea urchin: biology, anatomy, ecology, and human uses Sea urchin Comprehensive overview of sea urchins (class Echinoidea): form, anatomy, feeding, habitat, ecological role, edible species, and notable facts about their unique features.
Seabirds: biology, behaviour, and significance Seabird Overview of seabirds — birds adapted to life at sea, their adaptations, evolution, feeding, breeding, migrations and conservation concerns.
Seahorse (Hippocampus): biology, behavior, and conservation Seahorse Seahorses are small marine teleost fishes of the genus Hippocampus, known for their horse-like heads, upright posture, male pregnancy, and specialised habitats. This article covers…
Seasonal breeder (animal reproduction) Seasonal breeder Animals that confine mating to particular times of year, timed to environmental cues (day length, temperature, food, rainfall) so offspring are born when survival prospects are bes…
Secretarybird (Sagittarius serpentarius): an African terrestrial raptor Secretarybird A large, long-legged bird of prey native to sub-Saharan Africa, notable for hunting on foot, a snake-focused diet, distinctive crest, and its placement in a unique raptor family.
Segisaurus Segisaurus was a small, lightly built early theropod dinosaur known from a single partial skeleton found in what is now Arizona. It helps illuminate early Jurassic theropod anatomy…
Segnosaurus: the slow-lizard therizinosaur of the Late Cretaceous Segnosaurus Segnosaurus was a large herbivorous theropod (a therizinosaur) from the Late Cretaceous of Mongolia, known from partial skeletons and notable for its long neck, strong pelvis and l…
Sei whale Sei whale (Balaenoptera borealis): a fast, streamlined baleen whale of temperate oceans; feeds on small plankton, forms small pods, and was heavily reduced by commercial whaling.
Selous' zebra (Equus quagga borensis) Selous' zebra An overview of Selous' zebra, a distinct plains zebra subspecies: appearance, range in East Africa, behavior, conservation concerns, and how it differs from similar subspecies.
Semiaquatic: organisms that divide life between water and land Semiaquatic Overview of semiaquatic organisms: definition, adaptations, representative groups, life cycles, ecological roles, and conservation concerns for animals and plants living both in wa…
Senegal bushbaby (Galago senegalensis) Senegal bushbaby A small nocturnal strepsirrhine primate from sub-Saharan Africa, the Senegal bushbaby is an agile leaper with large eyes, varied vocalizations and a diet of insects, fruit and tree…
Serum amyloid A (SAA): acute‑phase protein, functions, and clinical importance Serum amyloid A Serum amyloid A proteins are acute‑phase apolipoproteins produced mainly by the liver; they participate in lipid transport, inflammation and can accumulate in AA amyloidosis and ar…
Serval (Leptailurus serval) Serval A medium-sized African wild cat known for long legs, large ears and agile hunting; its biology, behavior, distribution, and relationship with people are described.
Sessility (zoology): animals that live attached to a surface Sessility (zoology) Sessility in zoology describes animals whose adult stage is fixed to a substrate. Common in marine and freshwater species (corals, barnacles, sponges, mussels) with motile larvae a…
Setzer's mouse-tailed dormouse (Myomimus setzeri) Setzer's mouse-tailed dormouse A little-known species of dormouse in the family Gliridae, Myomimus setzeri is endemic to Iran. This article summarizes its identity, likely ecology, conservation concerns and rese…
Seven-arm octopus (Haliphron atlanticus) Seven-arm octopus A deep-water octopus known as the seven-arm octopus; notable for its large size, concealed hectocotylus (making it appear to have seven arms), and rare, scattered records worldwide…
Seychelles parakeet (Psittacula wardi) Seychelles parakeet An extinct parrot species once endemic to the Seychelles. Psittacula wardi inhabited island forests; it disappeared after human colonization, habitat loss and introduced predators.…
Seymouria: amphibian-like terrestrial tetrapod of the early Permian Seymouria Seymouria was a small, reptile-like seymouriamorph from the early Permian. Adults were well adapted to land while larvae were aquatic, showing an amphibian life history with terres…
Shaheen falcon (Falco peregrinus peregrinator) Shaheen falcon A resident subspecies of the peregrine falcon found in the Indian subcontinent and Sri Lanka, noted for its dark plumage, high-speed hunting and cultural importance in South Asia.
Shanag — small dromaeosaurid genus Shanag Shanag is a small carnivorous dromaeosaurid dinosaur from the Early Cretaceous of Asia, known for its lightweight build, predatory adaptations and relationship to other raptor-like…
Shantungosaurus — giant Late Cretaceous hadrosaur from Shandong, China Shantungosaurus Shantungosaurus is a very large hadrosaurid dinosaur from the Upper Cretaceous Wangshi Formation of Shandong, China, known from several incomplete skeletons and notable for its hug…
Shark: biology, evolution, diversity, and human interactions Shark Sharks (Selachimorpha) are cartilaginous fishes with diverse forms, long fossil history, varied feeding strategies and important ecological roles; this article outlines anatomy, ev…
Shell (zoology): protective external coverings of animals Shell (zoology) Hard or semi‑rigid external coverings produced by animals — composition, major groups (molluscs, crustaceans, echinoderms, turtles, armadillos), functions, growth and evolutionary…
Shepherd: roles, practices, history and cultural importance Shepherd Overview of shepherding: duties, tools, historical development, pastoral systems, animal management, regional practices and modern adaptations in agriculture and culture.
Shetland Sheepdog (Sheltie): Overview, Appearance, Temperament, and Care Shetland Sheepdog Compact, intelligent herding dog from the Shetland Islands. Known as the Sheltie, it has a long double coat, strong herding instincts, high trainability, and specific grooming and…
Shiba Inu — compact Japanese spitz-type dog breed Shiba Inu The Shiba Inu is a small-to-medium Japanese spitz-type dog bred originally for hunting. Known for its foxlike appearance, bold temperament, and cultural presence (including the Dog…
Shield bug (Acanthosomatidae): overview, biology and significance Shield bug Acanthosomatidae, commonly called shield bugs, are a small family of true bugs with about 55 genera and ~200 species. This article covers their appearance, behavior, ecology, and i…
Shih Tzu — Small long-coated companion dog Shih Tzu A small, long-coated companion dog that originated in China. Known for its friendly temperament, flowing coat and royal associations; requires regular grooming and has some brachyc…
Shikoku (Japanese dog breed) Shikoku (dog) Shikoku is a medium-sized native Japanese breed from Shikoku island, traditionally a hunting dog. Noted for a harsh double coat and sesame coloring, it is alert, loyal, and active…
Ship's cat Domestic cats kept aboard vessels for pest control, companionship and superstition; a practice with ancient roots that influenced shipboard life, cargo protection and maritime folk…
Shoaling and Schooling: Collective Grouping in Fish Shoaling and schooling Shoaling and schooling are collective behaviours in fish where individuals form groups for social, defensive, foraging, and hydrodynamic benefits. Schooling denotes coordinated mot…
Shonisaurus: a giant Triassic ichthyosaur Shonisaurus Shonisaurus is a genus of very large ichthyosaurs from the Late Triassic, known chiefly from Nevada and also reported from British Columbia. Its remains inform studies of Triassic…
Short-beaked common dolphin Delphinus delphis, the short‑beaked common dolphin, is a widespread, social dolphin of warm temperate and tropical seas. This article covers identification, range, behavior, diet,…
Short-beaked echidna (Tachyglossus aculeatus) Short-beaked echidna Encyclopedia entry on the short‑beaked echidna: appearance, biology, distribution, reproduction and conservation of this spiny, egg‑laying monotreme of Australia and New Guinea.
Short-faced bear (Arctodus) Short-faced bear Arctodus, the extinct short-faced bears of Pleistocene North America, includes some of the largest terrestrial carnivores. This article summarizes their taxonomy, anatomy, ecology,…
Short-tailed shearwater (muttonbird) Short-tailed shearwater A migratory southern hemisphere seabird (Ardenna tenuirostris) known as the short-tailed shearwater or muttonbird; breeds in Tasmania and south‑eastern Australia and undertakes lon…
Shovelnose frog (Hemisus): burrowing frogs of sub‑Saharan Africa Shovelnose frog Shovelnose frogs (genus Hemisus) are small, round-bodied burrowing frogs from sub‑Saharan Africa. Known for their hardened, upturned snout and head‑first digging, they breed in und…
