Shark Definition

A shark is a type of fish belonging to the class Chondrichthyes, which also includes rays, skates, and chimeras. Sharks are known for their cartilaginous skeletons, streamlined bodies, and predatory nature

General Characteristics & Facts

Sharks are a diverse group of fish characterized by their streamlined bodies, cartilaginous skeletons, and rows of sharp teeth.

Sharks come in various sizes, ranging from the small dwarf lantern shark, which is about 6 inches long, to the massive whale shark, which can exceed 40 feet in length.

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They are apex predators, playing a crucial role in marine food chains by regulating populations of prey species and maintaining the balance of ecosystems.

Sharks have a remarkable sense of smell, aided by specialized receptors called ampullae of Lorenzini, which detect electrical fields produced by other animals.

They have multiple rows of teeth that continuously regenerate throughout their lifetime. Some species can shed thousands of teeth in their lifetime. Sharks exhibit diverse feeding behaviors, including carnivorous, scavenging, filter-feeding, and even some that primarily feed on plankton.

Reproduction in sharks varies among species. Some species even exhibit a form of internal incubation called ovoviviparity, where the eggs hatch inside the mother’s body.

Sharks have a slow growth rate and low reproductive capacity, making them vulnerable to overfishing and environmental changes.

While some species of sharks are known to be potentially dangerous to humans, unprovoked shark attacks are rare, and the vast majority of shark species pose no threat to humans.

Conservation efforts are essential to protect shark populations, as many species are threatened by habitat destruction, pollution, bycatch, and overfishing.

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Physical Characteristics

Body Shape: Sharks have a streamlined and torpedo-shaped body, which allows them to move swiftly and efficiently through the water.

Skeleton: Unlike most fish, sharks have a cartilaginous skeleton made of flexible and lightweight cartilage rather than bone. This skeletal structure provides flexibility, reducing the shark’s overall weight while maintaining strength and agility.

Skin: Shark skin is covered in dermal denticles, which are tiny, tooth-like scales. These denticles give shark skin a rough texture and provide hydrodynamic advantages by reducing turbulence and enhancing swimming speed.

Fins: Sharks have several distinct types of fins that aid in their locomotion and stability in the water. These include the pectoral fins located on the sides of their body and the dorsal fin on their back.

Teeth: Sharks are known for their multiple rows of sharp, serrated teeth. They continually replace their teeth throughout their lives, as older or damaged teeth are shed and replaced by new ones.

Gills: These slits allow them to extract oxygen from the water by passing it over their gills, facilitating respiration.

Senses: Sharks have a highly developed sensory system. They possess excellent vision, with some species able to see in low-light conditions. Their sense of smell is particularly acute, allowing them to detect blood and trace amounts of chemicals in the water.

Coloration: Shark coloration varies among species and can provide camouflage or serve as a form of warning or mimicry. Some sharks exhibit countershading, where their dorsal (upper) side is darker to blend with the depths below, while their ventral (lower) side is lighter to blend with the brighter surface above.

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Scientific Classification

Kingdom: Animalia (Animals)

Phylum: Chordata (Chordates)

Class: Chondrichthyes (Cartilaginous fishes)

Subclass: Elasmobranchii (Sharks, rays, and skates)

Superorder: Selachimorpha (Sharks)

Key Locations

Great Barrier Reef, Australia
Gulf of Mexico, United States
Eastern coast of South Africa, including Durban and Cape Town
Maldives
Bahamas
Galapagos Islands, Ecuador
Red Sea, including Egypt and Saudi Arabia
Shark Bay, Western Australia
California coast, United States
Costa Rica, including Cocos Island
Fiji
Seychelles
Hawaii, United States
Thailand, including the Andaman Sea

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Shark FAQs

What does Shark eat?

Fish:
Marine Mammals
Cephalopods and Crustaceans

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Shark Definition | Characteristics & Facts