# Outline of sharks

The following outline is provided as an overview of and topical guide to sharks:
Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 440 million years ago, before the time of the dinosaurs.

## Fields that study sharks

* Ichthyology – branch of zoology devoted to fish (including sharks)
* Meristics – branch of ichthyology that relates to counting features of fish, such as the number of fins or scales

## Description

A shark, also called a "selachimorph", can be described as all of the following:
* Animal – multicellular, eukaryotic organism of the kingdom Animalia or Metazoa. An animal's body plan eventually becomes fixed as it develops, although some types of animal undergo a process of metamorphosis later on in their life. Most kinds of animal are motile, meaning they can move spontaneously and independently.
** Chordate – Chordates (phylum Chordata) are animals which are either vertebrates or one of several closely related invertebrates.
*** Fish – gill-bearing aquatic vertebrate (or craniate) animal that lacks limbs with digits.
**** Chondrichthye (cartilaginous fish) – jawed fish with paired fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone.
***** Elasmobranch – member of the subclass Elasmobranchii, which includes sharks, rays, and skates.
* Predator – organism that attacks and feeds on prey (the organism that is attacked).
** Apex predator – some shark species are apex predators, that is, predators with no predators of their own, residing at the top of their food chain.

### Biological classification

* Kingdom: Animalia
* Phylum: Chordata
* Class: Chondrichthyes
* Subclass: Elasmobranchii
* Superorder: Selachimorpha

## Types of sharks

List of sharks Subdivisions of the biological classification Selachimorpha include:
* Carcharhiniformes – ground sharks
* Heterodontiformes – bullhead sharks
* Hexanchiformes – the five extant species of the most primitive types of sharks
* Lamniformes – mackerel sharks
* Orectolobiformes – includes carpet sharks, including zebra sharks, nurse sharks, wobbegongs, and the whale shark
* Pristiophoriformes – includes sawsharks
* Squaliformes – includes gulper sharks, bramble sharks, lantern sharks, rough sharks, sleeper sharks and dogfish sharks
* Squatiniformes – angel sharks
* † Cladoselachiformes
* † Hybodontiformes
* † Symmoriida
* † Xenacanthida (Xenacantiformes)

## Shark behavior

* Predation
** Apex predator
* Shark threat display – Behaviour shown by some sharks when threatened
* Spy hopping – Raising the head out of the water

### Shark attacks

Shark attack
* International Shark Attack File
* List of fatal shark attacks in the United States
* Jersey Shore shark attacks of 1916 – series of shark attacks along the coast of New Jersey between July 1 and July 12, 1916
* Summer of the Shark – the name given to the summer of 2001 by American media outlets capitalizing on a bull shark attack and subsequent shark attacks

## Range and habitats of sharks
### Range

* Bodies of water in which sharks can be found include:
** Seas: all
** Freshwater – some species of shark can live both in seawater and freshwater, and include:
*** Bull shark
*** River shark
*** Sandbar shark
* Depths: from the surface down to depths of 2,000 metres (6,600 ft).

### Habitats

* White Shark Cafe – remote mid-Pacific Ocean area noted as a winter and spring habitat of otherwise coastal great white sharks

#### Sharks in captivity

Sharks in captivity
* Shark tank
* Shark tunnel – underwater tunnel that passes through an aquarium that keeps sharks

## Shark anatomy

* Physical characteristics of sharks – shark skeleton, respiration and skin
** Dermal denticle – small outgrowths which cover the skin of sharks
** Ampullae of Lorenzini – sensing organ that helps sharks and fish to sense electric fields
** Electroreception – the biological ability to perceive electrical impulses (see also Ampullae of Lorenzini)
** Lateral line – sense organ that detects movement and vibration in the surrounding water
** Shark cartilage – material that a sharks' skeleton is composed of
** Shark teeth
** Spiracle – pumps water across gills
** Clasper – the anatomical structure that male sharks use for mating
** Fish anatomy – generic description of fish anatomy

## Protective equipment

* Drum lines
* Shark net – submerged net placed around beaches to reduce shark attacks on swimmers
* Shark proof cage – cage from which a SCUBA diver can examine sharks more safely
* Shark repellent – method of driving sharks from an area, object, person, or animal
** Magnetic shark repellent – use of permanent magnets to repel sharks
** Protective oceanic device – first successful electronic shark repellent
* Shark suit

## Shark fishing

* Drivers of the shark trade
* Land-based shark fishing – fishing for sharks from land such as a beach, shoreline, jetty, pier, or bridge
* Shark finning – the removal of shark fins for commercial purposes

## Shark conservation

* 1992 cageless shark-diving expedition – first publicized cageless dive with great white sharks which contributed to changing public opinions about the supposed "killing machine"
* Shark Alliance – coalition of nongovernmental organizations dedicated to restoring and conserving shark populations by improving European fishing policy
* Shark Conservation Act – proposed US law to protect sharks
* Shark sanctuary – Palau's first-ever attempt to prohibit taking sharks within its territorial waters
* Shark tourism – form of ecotourism showcasing sharks
* Shark Trust – A UK organisation for conservation of sharks

## Notable sharks

* Stronsay Beast – large, dead creature washed ashore on Stronsay, in the Orkney Islands, after a storm in 1808, later presumed to be a basking shark

## Notable researchers and people

* Peter Benchley – author of the novel Jaws, later worked for shark conservation
* Eugenie Clark – American ichthyologist researching poisonous fish and the behavior of sharks; popularly known as The Shark Lady
* Leonard Compagno – international authority on shark taxonomy, best known for 1984 catalog of shark species (FAO)
* Jacques-Yves Cousteau – French naval officer, explorer, ecologist, filmmaker, innovator, scientist, photographer, author and researcher who studied the sea and all forms of life in water including sharks
* Ben Cropp – Australian former shark hunter, who stopped in 1962 to produce some 150 wildlife documentaries
* Richard Ellis – American marine biologist, author, and illustrator.
* Rodney Fox – Australian film maker, conservationist, survivor of great white shark attack and one of the world's foremost authorities on them
* Andre Hartman – South African diving guide best known for free-diving unprotected with great white sharks
* Hans Hass – diving pioneer, known for shark documentaries
* Mike Rutzen – great white shark expert and outspoken champion of shark conservation; known for free diving unprotected with great white sharks
* Ron and Valerie Taylor – ex-spearfishing champions who switched from killing to filming underwater documentaries
* Rob Stewart (filmmaker) – Canadian photographer, filmmaker and conservationist. He was best known for making and directing the documentary film Sharkwater