Search results
Sharks range in size from the small dwarf lanternshark ( Etmopterus perryi ), a deep sea species that is only 17 centimetres (6.7 in) in length, to the whale shark ( Rhincodon typus ), the largest fish in the world, which reaches approximately 12 metres (40 ft) in length. [2]
- Overview
- Description and habits
- GeneratedCaptionsTabForHeroSec
shark, any of numerous species of cartilaginous fishes of predatory habit that constitute the order Selachii (class Chondrichthyes).
Sharks, together with rays and skates, make up the subclass Elasmobranchii of the Chondrichthyes. Sharks differ from other elasmobranchs, however, and resemble ordinary fishes, in the fusiform shape of their body and in the location of their gill clefts on each side of the head. Though there are exceptions, sharks typically have a tough skin that is dull gray in colour and is roughened by toothlike scales. They also usually have a muscular, asymmetrical, upturned tail; pointed fins; and a pointed snout extending forward and over a crescentic mouth set with sharp triangular teeth. Sharks have no swim bladder and must swim perpetually to keep from sinking to the bottom.
Shark species are nondescript in colour, varying from gray to cream, brown, yellow, slate, or blue and often patterned with spots, bands, marblings, or protuberances. The oddest-looking sharks are the hammerheads (Sphyrna), whose heads resemble double-headed hammers and have an eye on each stalk, and the wobbegongs (family Orectolobidae), whose skin flaps and protective coloration closely resemble the seafloor. The vernacular of shark names indicate colours in living species, such as the blue (Prionace glauca), the white (Carcharodon carcharias; also known as the great white shark), and the lemon (Negaprion brevirostris) shark.
Britannica Quiz
Understanding Megalodon
The whale shark (Rhincodon typus) and the basking shark (Cetorhinus maximus), both of which may weigh several tons, are harmless giants that subsist on plankton strained from the sea through modified gill rakers. Whale sharks may grow up to 18 metres (59 feet) in length, whereas basking sharks may reach 14 metres (46 feet) fully grown. All other sharks prey on smaller sharks, fish, squid, octopuses, shellfish, other invertebrates, and, in some species, trash. The largest among the more predatory species is the voracious 6-metre (20-foot) white shark, which attacks seals, dolphins, sea turtles, large fish, and occasionally people. The more sluggish Greenland shark (Somniosus microcephalus) of cold deep waters feeds on seals, large fish, and even swimming reindeer; they may also scavenge whale carcasses.
Normally, sharks feed on fish, often attacking in schools. Open-ocean species such as the mackerel (Lamna), mako (Isurus), and thresher (Alopias) sharks frequently feed near the surface and are much sought after with rod and reel for sport. Beautifully streamlined and powerful swimmers, those open-ocean sharks are adept at feeding on fast tuna, marlin, and the like. Bottom-feeding species of sharks are stout, blunt-headed forms that tend to have more-sluggish habits. The shellfish eaters among them have coarse, pavementlike, crushing teeth.
Special offer for students! Check out our special academic rate and excel this spring semester!
Learn about sharks, the cartilaginous fishes of predatory habit that have more than 400 living species. Find out their characteristics, habitats, diets, threats, and human interactions.
- Jeffrey Carrier
Learn about the world's oldest and most diverse fish, from their skeletons and teeth to their diets and migrations. Find out how sharks are threatened by overfishing, climate change, and human activities.
- 5 min
Learn about sharks, their diversity, importance and threats from overfishing, demand for fins and bycatch. Find out what WWF is doing to protect sharks and rays and how you can help.
People also ask
Are sharks elasmobranch?
Why are sharks important?
Is a shark a ray?
Are shark fins a threat to shark species?
Jul 4, 2022 · published 4 July 2022. Older than the dinosaurs and ecologically vital, sharks deserve more than our fear. Great white sharks aren't as scary as you might think.(Image credit: by wildestanimal...
Learn about the diversity, anatomy, evolution and ecology of sharks, the top predators of the ocean. Find out how sharks are threatened by fishing, finning and fear, and what is being done to protect them.
