To keep heat from leaving the body, the dolphin has a thick layer of fat just below its skin. Blubber holds in its body heat, and keeps out the cold. The dolphin also has special blood vessels that soak up heat and carry it back to the center of the body. A dolphin's temperature is normally 96 degrees F to 98 degrees F. A dolphin's body can overheat if it swims fast over a long period of time. Overheating can cause a dolphin to get too tired and die.
All dolphins have two flippers and a tail fin.
Most dolphins also have a dorsal fin on their backs. Another name for the tail fin is fluke. The dolphin uses its fluke to push itself forward in the water. There are no bones to hold up a dolphin's tail fin. Tough strands of tissue called ligaments harden the tail fin and attach it to the tail vertebrae.