Marine Life · Chondrichthyes

Sharks

Selachimorpha (superorder)

Varies by Species

Sharks are cartilaginous fish — there are more than 350 different kinds. Well-known species such as the great white shark, tiger shark, and the hammerhead are apex predators, at the top of the underwater food chain. Their extraordinary skills as predators fascinate and frighten humans, even as their survival is under serious threat from fishing and other human activities.

Classification

Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Super Order: Selachimorpha

Size

The largest shark is the whale shark, measuring up to 60 feet in length. The smallest is the deepwater dogfish shark.

Habitat

Greatly varied — some species inhabit shallow coastal regions, others live in deep waters, ocean floors, and the open ocean. Some inhabit both salt and fresh water.

Description

Incredibly diverse in size, shape, habitat, diet, and behavior. A shark’s skin is made up of a series of scales.

Diet

Most sharks are carnivores, preying on fish and sea mammals like dolphins, other shark species, and seals, as well as turtles and seagulls. Whale sharks, the largest sharks, eat plankton.

Communication

Can hear sounds at very low frequencies.

Gestation

Five to six months up to two years, depending on the species.

Birth

More than half of shark species give birth to live pups; some sharks instead release eggs that hatch later.

Sexually Mature

Many species don’t reach sexual maturity until their teens.

Life Span

Varies by species, but most sharks live 20-30 years.

Did You Know?

Sharks have upper and lower eyelids, but they do not blink.