Dolphins are smart, sociable aquatic mammals that live in every ocean on the planet. Scientists aren't sure why they do it, but dolphins are known for leaping above the surface of the water as they swim.
Dolphins are one of the most commonly recognized and beloved sea creatures, in part because they are gregarious and friendly. Their playful nature and intelligence have brought dolphins into close contact with humans, not always to their benefit. Scientists have learned that dolphins live longer, happier lives when they're not in captivity, so you're less likely to see dolphins at an aquarium than in the past. Dolphins are mammals, giving birth to live babies, which may explain the Greek root of dolphin, delphys, meaning "womb."