Hopefully you already know that dolphins are not fish. Dolphins are warm blooded mammals like us. They breath air through a nostril on the top of their heads called a blowhole. Because dolphins breath air, they must surface periodically. Fish, however, breath by using gills underwater, and therefore do not need to surface. Many fish also have scales, which dolphins do not have. Instead, the skin of a dolphin feels rubbery. A layer of fat, called blubber, under their skin keeps them warm. The locomotion of fish and dolphins is also different. Fish swim by moving their tails from side to side (horizontally). However, dolphins swim by moving their tails up and down (vertically).
How many kinds of dolphins are there?
This question will probably never be answered correctly. As humans, we want to put everything we know of into a group. Some people like large groups with some variation and others like small, precise groups. Not everyone agrees about what marine dolphins deserve their own species name and what ones do not. I currently have 32 species of marine dolphins listed. I am pretty sure that this covers all the species accurately. Most people agree that there are six species of porpoises and five species of river dolphins
Dolphins can understand and interpret some words and actions, they cannot understand us word for word like in the TV show. Even though dolphins may not understand us completely, they might have their own languages. In fact, many people believe that dolphins communicate with languages.
