A dolphin is a marine mammal belonging to the family Delphinidae, which includes various species known for their intelligence and social behavior. These creatures are part of the cetacean group, which also includes whales and porpoises. Dolphins are characterized by their streamlined bodies, a beak-like snout, and a dorsal fin. They are known for their playful nature, often seen surfing the waves or leaping out of the water. Dolphins communicate using a complex system of clicks and whistles and are often studied for their advanced cognitive abilities. They inhabit oceans and rivers worldwide and are often seen in pods.