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They take power naps -

Dolphins are unable to breathe underwater, so how do they sleep without drowning? They take 15-20-minute naps!

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They take power naps -

But they don’t just fall asleep completely. They actually just rest one hemisphere of their brain. This way they can still swim, breathe, and notice predators.

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Pregnancy and motherhood -

Pregnancies last approximately between nine to 17 months and they usually give birth to one calf.

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Calves -

Calves are nursed between one to two years, and then usually stay with their mothers for another one to seven years.

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Their skin regenerates really fast -

A dolphin can regenerate the outer layer of its skin in just two hours! This is the secret to their smooth skin. It's believed that this is to reduce drag while they swim.

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They’re very social -

Dolphins have complex social networks. Scientists discovered that they actually make friends with other dolphins. In this aspect, they are similar to humans, as they prefer the company of certain dolphins more than others.

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They communicate through sounds -

They use clicks and whistles to communicate with each other underwater.

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They communicate through sounds -

In addition to the click and whistles, they also produce loud burst-pulse sounds. These can be used to scare off a predator, or used by female dolphins to reprimand their offspring when necessary.

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Their language hasn't been deciphered -

Scientists have been studying dolphin vocalizations for a long time, but their language still remains a mystery.

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Their language hasn't been deciphered -

Scientists are still trying to find the link between the animals' vocalizations to their behavior.

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Dolphins respond to their name -

Every dolphin has its own signature whistle. How cool is that?

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Dolphins respond to their name -

They use their unique whistles to call out to one another. Scientists believe they might even be able to remember other dolphins' whistles after years apart.

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They use echolocation to navigate -

Dolphins have their own sonar. This allows them to detect other objects via sound waves.

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They use echolocation to navigate -

They produce click sounds, and by listening to the echo produced when those sounds bounce off objects, dolphins are able to determine their surroundings and navigate.

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They don't use their teeth as we do -

Dolphins have teeth, but they don't use them to chew food, as we do.

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They don't use their teeth as we do -

Instead, dolphins use their teeth to catch prey and swallow it whole, without chewing them.

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They live in groups -

Dolphins live in groups, called pods. This is how they organize themselves to hunt prey, escape from predators, and even care for sick or injured dolphins.

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They live in groups -

Sometimes these pods merge and they form a superpod that can consist of over 1,000 dolphins!

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There are lots of dolphin species -

You're probably more familiar with bottlenose dolphins, but there are actually 44 dolphin species.

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There are lots of dolphin species -

Killer whales, also known as Orcas, are the largest dolphin species (yes, they're dolphins).

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Porpoises are not dolphins -

They might look alike, but they’re not even from the same family. When compared to porpoises, dolphins are usually bigger and have longer beaks and curved dorsal fins.

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Porpoises are not dolphins -

When compared to dolphins, these small-toothed whales have more triangular dorsal fins and different-looking teeth.

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They are used by the U.S. Navy -

The Navy Marine Mammal Program at San Diego's Space and Naval Warfare Systems Command trains dolphins. Dolphins are trained to find mines, spot enemy divers, and used to guard a nuclear arsenal.

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They've been used in war -

Dolphins have also been used during the conflicts in Vietnam and the Persian Gulf.

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Some dolphin species are endangered -

This is mostly due to hunting (their meat is eaten in parts of Japan and the Faroe Islands), overfishing (many get caught up in fishing nets), and pollution.

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Some dolphin species are endangered -

Rising ocean temperatures are also changing the habitats of a number of species, including those that dolphins eat.

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Lifespan -

This varies depending on the species, but they live longer in the wild than when kept in captivity.

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Lifespan -

But some do live long lives in captivity. Nellie, a dolphin who lived in a marine entertainment park in Florida, lived until he was 61.

See also: The world's most incredible aquatic mammals

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