Some are regular residents of the area while others are more migratory. You might wonder how the researchers know they are looking at different dolphins rather than the same few over and over again. Individuals are identified by the ragged edges of their dorsal fin because no two dolphins have the same dorsal fin markings. The very thin trailing fin edges are easily tattered due to normal wear and tear. By using high resolution photographs of these fins, researchers identify individual dolphins.
Dolphins have some unique behaviors and reflexes.
Navigating in murky water would be a big problem for humans, but not for dolphins. Dolphins communicate by using high-pitched whistles and clicks which give off sound waves that travel through water and bounces off solid objects, causing an echo. A dolphin's brain is adapted to understand the echoes that travel through water. The male dolphin has another special adaptation. He is able to sleep below the surface of the water because he has a special reflex action that triggers about every fifteen minutes to tell him to rise to the surface to get a breath of air.