characteristic of sea dolphin species

Sea dolphin species (Delphinidae) inhabit open oceans, with a small part living in coastal waters or rivers. The sea dolphin spout of some species is long and slender because of its elongated jawbone. In the elongated jawbone there are many conical teeth (some species have 130 teeth in each jaw). The pectoral fins allow the dolphins to steer and control their swimming speed. The dolphin's dorsal fin functions to control the direction of movement and stability in water. Dolphins do not have prominent external ear openings. Their ear opening is a small gap (located behind the eye) that is not connected to the middle ear.
The scientists found that the sound is transmitted to the inner and middle ear by the lobes located inside the lower jaw and by the various bones in the skull.
When light travels from air to water, its speed will change so as to create an optical effect called refraction. Fortunately, dolphin lenses and corneas have adapted to overcome this problem so they can see clearly inside and outside the water. Dolphins, like all toothed whales, have no lobes and olfactory nerves. Because the dolphins do not have the anatomical feature of smell, most likely the sense of smell is less developed