Anatomy of dolphins
The word "dolphin" is of Greek precedence. This term can be used to call oceans dolphins "Delphinidae" and to call every representative of dolphins that may also belong to the species that live in rivers "Platanistoidea" and to call the representatives of Odontoceti that are cetacean creatures with teeth.
Dolphins have elongated body that is specially created for high speed swimming in water. The main colour of dolphins is grey with light-grey and vice versa and sometimes they have black spots on their back. Usually dolphins have numerous lines and patterns of different colours on their bodies.
There is special organ in the head of a dolphin that is responsible for echolocation. Many species of dolphins have elongated teeth that form very interesting jaws. The mouth of bottle-nosed dolphins has the form of arch that is why they can smile. Dolphins may have a great number of teeth. Sometimes they may have 200 teeth and even more.
The brain of dolphins is really big. It is well-developed structure that usually causes a lot of discussions on the topic of mental possibilities of dolphins.
In difference from other mammals dolphins don't have any hair, but they are born with hair around beaks and sometimes hair appears in belly of the mother. The only conformance exception is the fresh-water dolphin Bouoto that doesn't have any hair at all.
Many dolphins have good eye-sight. Their hearing is much better than possibilities of people's hearing. Despite the fact that they have little ears on both sides of the head, people consider that they are not able to hear in water and the signals are transmitted through vibration of middle ear.