Dolphins are aquatic mammals, which means they are warm blooded, feed their young milk, and need to breathe air.
When dolphins sleep, only half their brain sleeps at a time so they can come up for air. The eye opposite to the side of the brain that is asleep will close and the other eye will stay open.
There are 44 species of dolphin. You can see a list of all the species here: How many types of dolphin are there?
Dolphins can be found in every ocean on Earth. Some species even live in rivers. Most dolphin species prefer warmer water, but some can be found in colder water.
Dolphins are carnivores. Most dolphins eat fish and squid. The killer whale (also known as orca) will also eat larger animals like sea birds, seals, sea turtles, sharks, and rays.