Portal:Sharks - Wikipedia

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Welcome to the shark portal

Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the Batoidea (rays and kin). Some sources extend the term "shark" as an informal category including extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as Cladoselache and Doliodus first appeared in the Devonian Period (419–359 million years), though some fossilized chondrichthyan-like scales are as old as the Late Ordovician (458–444 million years ago). The earliest confirmed modern sharks (selachimorphs) are known from the Early Jurassic around 200 million years ago, with the oldest known member being Agaleus, though records of true sharks may extend back as far as the Permian.

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. They are found in all seas and are common to depths up to 2,000 metres (6,600 ft). They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river sharks, which can be found in both seawater and freshwater, and the Ganges shark, which lives only in freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth.

Several species are apex predators, which are organisms that are at the top of their food chain. Select examples include the bull shark, tiger shark, great white shark, mako sharks, thresher sharks, and hammerhead sharks. (Full article...)

The oceanic whitetip shark, Carcharhinus longimanus, is a large pelagic shark of tropical and warm temperate seas. It is a stocky shark, most notable for its long, white-tipped, rounded fins.

This aggressive but slow-moving fish dominates feeding frenzies, and is a danger to survivors of oceanic shipwrecks and downed aircraft — it has attacked more humans than all other shark species combined. Recent studies have shown that its numbers are in steep decline as its large fins are highly valued as the chief ingredient of shark fin soup and, as with other shark species, the oceanic whitetip faces mounting pressure from fishing throughout its range.

Did you know (auto-generated)

... that Timo Meier became the first player in San Jose Sharks franchise history to score five goals in one game when he was 25?
... that since 2018, IKEA's stuffed toy shark Blåhaj has become a popular Internet meme and an icon of the online transgender community?
... that Hixxy and Sharkey created a schism in the UK rave music scene in 1995?
... that "the Hurricane Shark is real"?
... that Alexis Sharkey's last Instagram post before her murder documented her travels to Tulum, Mexico?
... that the ampullae of Lorenzini enable sharks to sense electric fields?

WikiProjects

WikiProjects related to sharks:

... that the whitetip reef shark may have contributed to the Hawaiian myth of ʻaumākua, family guardian spirits, due to the "loyalty" of sharks that stay in the same area for years?
... that individual smalltooth sand tigers have been documented returning to the same location off Lebanon every summer?
...that Mustelus hacat is a species of smooth-hound shark discovered in 2003 in the Sea of Cortez, off the coast of Mexico?
... that during the summer the finetooth shark is found exclusively in water less than 10 m (30 ft) deep?
... that the Canary Islands are one of the few places left where there are still substantial numbers of angelsharks, once common all around Europe?
...that whilst most sharks are poikilothermic, species in the family Lamnidae are homeothermic?

General images

The following are images from various shark-related articles on Wikipedia.

Great white shark cages at Isla Guadalupe, Mexico (from Shark cage diving)
Shark cage diving (from Shark tourism)
Depiction of shark anatomy including eggs, pups, and the liver (from Shark anatomy)
Lateral and cross section view of shark's red and white locomotor muscles (from Shark anatomy)
A ventral dissection of a pregnant female dogshark exposing its internal gill slits and internal spiracles. (from Shark anatomy)
Shark Anatomy (50693674756) (from Shark anatomy)
Distribution of highly sensitive ampullae of Lorenzini across the shark's head and rostrum. (from Shark agonistic display)
Placoid Scale (from Shark anatomy)
The major features of sharks (from Shark anatomy)
Anti-cull protesters on Perth's Cottesloe Beach in Western Australia in 2014 (from Shark culling)
The whale shark, the world's largest fish, is classified as Endangered.

Binding legislation and harvest management strategies... are urgently needed to address the disproportionate impact of fisheries on cartilaginous fishes.

– IUCN global study 2010

(from List of threatened sharks)
Sharksucker (Echeneis naucrates) (from Shark agonistic display)
In a milestone decision in 2013, CITES prohibited international trade in the fins of the scalloped hammerhead (pictured) and four other shark species. (from List of threatened sharks)
Sharks swimming outside shark-proof cage with people inside (from Shark cage diving)
A dissected view of the unique four-chambered heart of the sharkChambers: Sinus Venosus, Atrium, Ventricle, Conus Ateriosus (from Shark anatomy)
The gill slits of a whale shark flaring as it expels water from its pharyngeal cavity. (from Shark anatomy)
White shark cage diving near Gansbaai in South Africa (2015) (from Shark cage diving)
A 14-foot (4.3 m), 1,200-pound (540 kg) tiger shark caught in Kāne'ohe Bay, Oahu, in 1966
This grey reef shark demonstrates countershading, with its darker dorsal surface and lighter ventral surface. (from Shark anatomy)
A sign at Pyramid Rock Beach in Hawaii warning about a shark sighting, 2015 (from Shark tourism)
Postural configuration of a Gray Reef Shark as it displays agonistic behaviour, in a sculpture (from Shark agonistic display)
Dorsal fin diagram with landmarks labeled. (from Shark anatomy)
Great white shark at Isla Guadalupe, Mexico, August 2006. Animal estimated at 11–12 feet (3.3 to 3.6 m) in length, age unknown. (from Shark tourism)
BranchiostomaLanceolatum PioM (from Shark anatomy)
Postural elements of the agonistic display of the Gray Reef Shark (from Shark agonistic display)
Clear agonistic behaviour observed in Great White Shark (from Shark agonistic display)