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How are dolphins different from fish?

Dolphins vary from fish in a number of ways. Both dolphins and fish have adapted to live their whole lives in the water, both have streamlined bodies and fins. But, dolphins are mammals and so they need regularly visit the surface to breathe air to survive, otherwise they would drown. Fish on the other hand extract oxygen from the water and do not need to surface.

Dolphins evolved from land mammals whose legs were underneath their bodies. As a result, dolphins tails move up and down as they swim, whereas a fish’s tail moves from side to side.

Dolphins are warm-blooded and have blubber to keep them warm. Fish are cold-blooded and are able to adjust to the different temperatures of the water without the need of body fat to keep them warm.

Most species of fish are also known to lay eggs and can lay hundreds of eggs in a single year. Dolphins give birth to a single baby once every 1 – 6 years and then feed their babies milk through their nipples.

Great white shark swimming near the surface of the water
A great white shark in the Gulf of Maine.

Amazing facts about whales and dolphins

Dive deeper into the world of whales and dolphins and learn more about their lives.

A humpback whale pokes its head partway out of the water, a behavior called spyhopping

Facts about whales

Amazing facts about whales, the largest mammals to live on Earth.

two dolphins diving down out of the water

Facts about dolphins

From the orca to the tiny vaquita, learn more about these creatures.

Northern Resident orca, Fife, swimming at the surface

Record breakers

Whales and dolphins hold some incredible records.

Breaching North Atlantic right whale

Brain power

Just how intelligent are whales and dolphins?

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Humpback whale spyhop

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Bottlenose dolphin calf breaching with its whole body out of the water

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Breaching North Atlantic right whale

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Orca spyhop

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