When you think of a dolphin, the picture that comes to mind is probably a bottlenose dolphin (Tursiops truncatus). Stars of sea-life theme-park entertainment acts and television programs, lively bottlenose dolphins delight onlookers with intricate tricks and amazing intelligence. Their perpetual "smiles" and playful antics make them appear friendly and tame, but the U.S. Fish and Wildlife Service says you should never try to interact with a wild dolphin.
Bottlenose dolphins get their name from their stubby snouts, called rostrums, which are about 3 inches long. Their sharp teeth serve for grasping rather than for chewing; bottlenose dolphins swallow their prey whole. Their eyes are on the sides of their heads, just beyond the corners of their mouths. You'll have to look closely to see ears, which are small holes below the eyes. On the top of their heads, bottlenose dolphins have blowholes, which they close off with a muscular flap when they go underwater and open when they surface.
A bottlenose dolphin's smooth, sleek body is suited to gliding through water. Mature, he reaches a length of 8 to 12 feet and weighs between 400 and 600 pounds. His smooth, thick skin feels rubbery to the touch. The gray skin on top of his body fades to white on his underbelly and under his jaw.
Fins, Flippers and Flukes
On each side of his body, a bottlenose dolphin has a flipper that averages 12 to 20 inches long. Flippers have internal structure similar to that of human hands. They help bottlenose dolphins steer through water and play an important role in regulating body temperature. The tall, sickle-shaped dorsal fin, which sits on the center of the dolphin's back, also helps regulate body temperature and may play a role in maintaining balance. The horizontal tail fins, known as flukes, help propel the dolphin through the water.
Bottlenose dolphins are energetic animals, often seen jumping completely out of the water, slapping their tail flukes on the surface of the water, and riding swells created by boats and whales. These social animals live in groups of 100 or more and communicate with each other using clicks, whistles and other sounds.
- dolphin Tursiops truncatus (bottlenosed dolphin) image by agno_agnus from Fotolia.com