American Oceans

Are Sharks Fish or Mammals?

Sharks are fascinating creatures that have captured the imagination of humans for centuries. But there is still some confusion about whether sharks are mammals or fish.

Whaler Reef Shark

The answer is quite simple: sharks are fish. While they share some characteristics with mammals, such as giving birth to live young, they are not classified as mammals.

Sharks are a type of fish that belong to the class Chondrichthyes, which includes other cartilaginous fish such as rays and skates. Unlike bony fish, which have skeletons made of bone, sharks have skeletons made of cartilage.

Sharks also have five to seven gill slits on the sides of their heads, which they use to extract oxygen from the water. While some species of sharks give birth to live young, most lay eggs. Sharks are also known for their sharp teeth and powerful jaws, which they use to catch and eat their prey.

Despite their differences from mammals, sharks are still some of the most fascinating creatures in the ocean.

With over 500 different species of sharks, each with their own unique characteristics and behaviors, there is still much to learn about these fascinating fish.

Whether you are a marine biologist studying shark behavior or simply an ocean enthusiast looking to learn more about these incredible creatures, there is no denying that sharks are some of the most fascinating animals on the planet.

Sharks: Fish or Mammals?

dangerous and deadly sharks

Sharks are one of the most fascinating creatures in the ocean. They are known for their sharp teeth, powerful jaws, and sleek bodies. But are sharks mammals or fish? Let’s explore this question in more detail.

Characteristics of Sharks

Sharks are a type of fish that have several unique characteristics. They have gills that allow them to extract oxygen from the water, and they are cold-blooded, meaning that their body temperature is regulated by the environment.

Sharks have a cartilaginous skeleton, which means that their bones are made of cartilage instead of bone. They also have a unique shape that allows them to swim efficiently through the water.

Classification of Sharks

Sharks belong to the class Chondrichthyes, which includes all cartilaginous fish. This class also includes rays and chimaeras.

Sharks are further classified into several different orders, including mackerel sharks, angel sharks, and ground sharks.

Types of Sharks

A Great White Shark

There are over 500 species of sharks, each with its own unique characteristics. Some of the most well-known species include the whale shark, tiger shark, mako shark, and hammerhead shark. Sharks can range in size from just a few inches to over 40 feet long.

Sharks can also reproduce in different ways. Some species lay eggs, while others give birth to live young.

Sharks that give birth to live young are either oviparous (laying eggs that hatch inside the mother) or ovoviviparous (keeping the eggs inside the mother until they hatch).

Sharks vs. Mammals


Mammals are a group of endothermic vertebrates that are characterized by the presence of mammary glands, hair, and a neocortex region in the brain that is responsible for complex cognitive processes.

They breathe air through lungs and give birth to live young, which they feed with milk produced by their mammary glands. Some examples of marine mammals include dolphins, whales, and orcas.


Sharks, on the other hand, belong to the class Chondrichthyes, which includes all elasmobranchs, or cartilaginous fish. Sharks lack many mammalian characteristics such as hair, lungs, and mammary glands.

Instead, they breathe through gills and give birth to live young, which are called pups. Sharks are known for their strong jaws and excellent predatory skills, making them top predators in the seas. Some well-known species of sharks include the great white shark and the whale shark.

While sharks and marine mammals share some similarities, such as giving birth to live young, they are fundamentally different creatures.

Sharks lack the complex cognitive processes and social behaviors exhibited by marine mammals, and they do not produce milk to feed their young. Additionally, sharks have a different skeletal structure and skin composition compared to mammals.

Sharks are also different from other fish, such as jawless fish, in that they have a cartilaginous skeleton instead of a bony one.

Furthermore, unlike marine mammals, sharks do not have flukes or tails that move up and down, but rather have tails and bodies that move from side to side.

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