There are 43 different species of dolphins that have been recognized. 38 of them are marine dolphins which are those that we are the most aware of and 5 of them are river dolphins. It can be very interesting to look at each of these species uniquely versus dolphins as a whole.
They are very entertaining due to the leaps that they make out of the water. Some of them leap up to 30 feet in the air as they do so. They have to come to the surface to for water at different intervals to get air. This can be from 20 seconds to 30 minutes between when they get air. The body of the dolphin is grayish blue and the skin is very sensitive to human touch and to other elements that could be in the water. Source: Dolphin Facts