Chondrichthyes is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fish, which have skeletons primarily composed of bone tissue. Chondrichthyes are aquatic vertebrates with paired fins, paired nares, placoid scales, conus arteriosus in the heart, and a lack of opecula and swim bladders. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates.
The hammerhead sharks are a group of sharks that form the family Sphyrnidae, named for the unusual and distinctive form of their heads, which are flattened and laterally extended into a cephalofoil. The shark's eyes are placed one on either end of this T-shaped structure, with their small mouths directly centered and underneath. Most hammerhead species are placed in the genus Sphyrna, while the winghead shark is placed in its own genus, Eusphyra. Many different— but not necessarily mutually exclusive—functions have been postulated for the cephalofoil, including sensory reception, manoeuvering, and prey manipulation. The cephalofoil gives the shark superior binocular vision and depth perception.
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 and are the sister group to the Batoidea. Some sources extend the term "shark" as an informal category including extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as Cladoselache and Doliodus first appeared in the Devonian Period, though some fossilized chondrichthyan-like scales are as old as the Late Ordovician. The oldest confirmed modern sharks (selachimorphs) are known from the Early Jurassic, about 200 million years ago, though records of true sharks may extend back as far as the Permian.
The great white shark, also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is the only known surviving species of its genus Carcharodon. The great white shark is notable for its size, with the largest preserved female specimen measuring 5.83 m (19.1 ft) in length and around 2,000 kg (4,410 lb) in weight at maturity. However, most are smaller; males measure 3.4 to 4.0 m, and females measure 4.6 to 4.9 m on average. According to a 2014 study, the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates, making it one of the longest lived cartilaginous fishes currently known. According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring. Great white sharks can swim at speeds of 25 km/h (16 mph) for short bursts and to depths of 1,200 m (3,900 ft).
The San Jose Sharks are a professional ice hockey team based in San Jose, California. The Sharks compete in the National Hockey League (NHL) as a member of the Pacific Division in the Western Conference, and are owned by San Jose Sports & Entertainment Enterprises. Beginning play in the 1991–92 season, the team initially played its home games at the Cow Palace, before moving to its present home, now named SAP Center at San Jose, in 1993; the SAP Center is known locally as "the Shark Tank". The Sharks are affiliated with the San Jose Barracuda of the American Hockey League (AHL) and the Wichita Thunder of the ECHL.
Jaws is a 1975 American thriller film directed by Steven Spielberg, based on the 1974 novel by Peter Benchley. It stars Roy Scheider as police chief Martin Brody, who, with the help of a marine biologist and a professional shark hunter, hunts a man-eating great white shark that attacks beachgoers at a summer resort town. Murray Hamilton plays the mayor, and Lorraine Gary portrays Brody's wife. The screenplay is credited to Benchley, who wrote the first drafts, and actor-writer Carl Gottlieb, who rewrote the script during principal photography.
The tiger shark is a species of ground shark, and the only extant member of the genus Galeocerdo and family Galeocerdonidae. It is a large macropredator, with females capable of attaining a length of over 5 m. Populations are found in many tropical and temperate waters, especially around central Pacific islands. Its name derives from the dark stripes down its body, which resemble a tiger's pattern, but fade as the shark matures.
The bull shark, also known as the Zambezi shark in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in rivers. It is known for its aggressive nature, and presence mainly in warm, shallow brackish and freshwater systems including estuaries and (usually) lower reaches of rivers. This aggressive nature is a reason for its population being listed as vulnerable on the IUCN Red List. Shark-culling occurs near beaches to protect beachgoers, which is one of the causes of bull shark populations continuing to decrease.
The whale shark is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of 18.8 m (61.7 ft). The whale shark holds many records for size in the animal kingdom, most notably being by far the most massive living non-cetacean animal. It is the sole member of the genus Rhincodon and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as Rhiniodon into Rhinodontidae.
A shark attack is an attack on a human by a shark. Every year, around 80 unprovoked attacks are reported worldwide. Despite their rarity, many people fear shark attacks after occasional serial attacks, such as the Jersey Shore shark attacks of 1916, and horror fiction and films such as the Jaws series. Out of more than 500 shark species, only three are responsible for a double-digit number of fatal, unprovoked attacks on humans: the great white, tiger, and bull. The oceanic whitetip has probably killed many more shipwreck and plane crash survivors, but these are not recorded in the statistics. Humans are not part of a shark's normal diet. Sharks usually feed on small fish and invertebrates, seals, sea lions, and other marine mammals. A shark attack will usually occur if the shark feels curious or confused.
The Cronulla-Sutherland Sharks are an Australian professional rugby league club based in Cronulla, in the Sutherland Shire, Southern Sydney, New South Wales. The Cronulla Sharks compete in the National Rugby League (NRL), Australasia's premier rugby league competition. The Sharks, as they are commonly known, were admitted to the New South Wales Rugby League premiership, predecessor of the Australian Rugby League and the current National Rugby League competition, in January 1967. The club competed in every premiership season since then and, during the Super League war, joined the rebel competition before continuing on in the re-united NRL Premiership. The Sharks have been in competition for 56 years, appearing in four grand finals, winning their first premiership in 2016 after defeating the Melbourne Storm at Stadium Australia.
Otodus megalodon, commonly known as megalodon, is an extinct species of giant mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. O. megalodon was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark, but has been reclassified into the extinct family Otodontidae, which diverged from the great white shark during the Early Cretaceous.
Thresher sharks are large mackerel sharks of the family Alopiidae found in all temperate and tropical oceans of the world; the family contains three extant species, all within the genus Alopias.
Shark fin soup is a soup or stewed dish served in parts of China, Taiwan, and Southeast Asia. The shark fins provide texture, while the taste comes from the other soup ingredients. It is commonly served at special occasions such as weddings and banquets, or as a luxury item.
The basking shark is the second-largest living shark and fish, after the whale shark. It is one of three plankton-eating shark species, along with the whale shark and megamouth shark. Typically, basking sharks reach 7.9 m (26 ft) in length. It is usually greyish-brown, with mottled skin, with the inside of the mouth being white in colour. The caudal fin has a strong lateral keel and a crescent shape. Other common names include bone shark, elephant shark, sailfish, and sunfish. In Orkney, it is called hoe-mother, meaning "the mother of the picked dogfish".
The Greenland shark, also known as the gurry shark or grey shark, is a large shark of the family Somniosidae, closely related to the Pacific and southern sleeper sharks. Inhabiting the North Atlantic and Arctic Oceans, they are notable for their exceptional longevity, although they are poorly studied due to the depth and remoteness of their natural habitat.
Shark cage diving is underwater diving or snorkeling where the observer remains inside a protective cage designed to prevent sharks from making contact with the divers. Shark cage diving is used for scientific observation, underwater cinematography, and as a tourist activity. Sharks may be attracted to the vicinity of the cage by the use of bait, in a procedure known as chumming, which has attracted some controversy as it is claimed to potentially alter the natural behaviour of sharks in the vicinity of swimmers.
Rodney Winston Fox is an Australian film maker, conservationist, survivor of an attack by a great white shark, and one of the world's foremost authorities on that species. He was inducted into the International Scuba Diving Hall of Fame in 2007. He was born in Adelaide.
Shark tourism is a form of eco-tourism that allows people to dive with sharks in their natural environment. This benefits local shark populations by educating tourists and through funds raised by the shark tourism industry. Communities that previously relied on shark finning to make their livelihoods are able to make a larger profit from diving tours while protecting the local environment. People can get close to the sharks by free- or scuba diving or by entering the water in a protective cage for more aggressive species. Many of these dives are done by private companies and are often baited to ensure shark sightings, a practice which is highly controversial and under review in many areas.
Shark Tank is an American business reality television series that premiered on August 9, 2009, on ABC. The show is the American franchise of the international format Dragons' Den, a Japanese TV series. It shows entrepreneurs making business presentations to a panel of five venture capitalists called "sharks" on the program, who decide whether to invest in their companies.
