As of November 2026, there are more than 500 kinds of sharks. They are different in many ways, but they share a few body parts. All of them are fish that breathe underwater with gills. They have no bones, because their skeleton is made of cartilage.

As of November 2026, sizes run from tiny to huge. The dwarf lanternshark is full size at under 8 inches, and the deep-water pygmy shark is about 8 inches. A white shark pup is about 4 feet long when it is born, and a great white can grow to about 20 feet long. Whale sharks are often about 18 to 32 feet long.

As of November 2026, the biggest fish in the sea is a shark, the whale shark. This giant eats very small sea animals called plankton. It swims with its mouth open and filters tiny food out of the water.

Senses help a shark find a meal. It has a very good sense of smell and is sometimes called a swimming nose. It hears well, with ears inside its head, and can pick up the sounds of fish splashing. Its lateral line picks up vibrations and flow in the water, which helps it sense nearby prey.

What sharks eat depends on the kind. Tiger sharks eat almost anything, like fish, turtles, birds and even garbage. Young white sharks eat bottom fish, smaller sharks, rays and schooling fish before they move on to seals. Adult great whites mostly hunt seals and sea lions.

Teeth are different from one kind of shark to the next. White shark teeth are broad, triangular and serrated. A whale shark's teeth are tiny and play little part in feeding. A shark loses teeth all its life and grows new ones to replace them. They can shed thousands of teeth in a lifetime, and some may shed 50,000.

A whale shark has light spots on its dark back. A great white has a white belly and a gray or brown back. Many sharks are dark on top and light underneath. This pattern, called countershading, helps to hide them.

Sharks are very old animals. As of November 2026, sharks as a group have lived in the sea for more than 400 million years, long before the first trees about 385 million years ago. Some sharks also live a very long time. Greenland sharks may live for centuries, which means hundreds of years. As of November 2026, one study put the age of a large female at about 392 years, give or take 120.

Words to know

• serrated: with jagged edges
• cartilage: bendy bone stuff
• centuries: hundreds of years

The short version

As of November 2026, there are more than 500 kinds of sharks, and they have lived in the sea for more than 400 million years. As of November 2026, a great white can grow to about 20 feet long, and the whale shark is the biggest fish in the sea.

Quick facts

• As of November 2026, there are more than 500 kinds of sharks.
• As of November 2026, a great white shark can grow to about 20 feet long.
• As of November 2026, the whale shark is the biggest fish in the sea.
• Sharks have no bones. Their skeleton is made of cartilage.
• As of November 2026, one study put the age of a large female Greenland shark at about 392 years, give or take 120.