The mode of life
Dolphins live in bands that are usually called schools that usually consist of 12 members. In seas with a great number of food schools may unite for some period of time creating big band-agglomeration. And this agglomeration may consist of more than thousand dolphins.
Dolphins communicate with each other using different click, snaps, and other sounds. They also use ultrasound for echolocation. The members of the group may change, but cetacean creatures have very thick and close relations and thanks to it they support injured and sick members of the school.
The cultural aspect of the life of dolphins was also discovered. Some dolphins taught their children to use instruments. They closed their mouths with lips during eating. Results, this ability passes from mothers to daughters in difference from other mammals where abilities pass not depending on the sex. And the ability to close the mouth with lips is not natural ability but acquired ability.
If dolphins see a person that approaches to them in water, they will invite him/her to join them playing. In 2006 people discovered that dolphins respond to names.
Sometimes dolphins may get cross with other dolphins. And you may notice a great number of scars on the body of old dolphins that are the scars from bites of other animals. People consider that the reasons for getting angry are the same as people's reasons. This anger may be the result of the quarrel with friends or the competition for the female-dolphin.