Dolphins are aquatic mammals which range from 1.7 to 9.5 meters in length and can weight from 50 kilograms to 10 tons. Their bodies are streamlined and their two limbs have turned into flippers. They lack external ear flaps, but have a tail fin and their heads are bulbous.
Dolphins have conical teeth and breathe through a blowhole. They also have a thick layer of fat, called blubber, to keep them warm in the water.