There are also some data concerning the phylogeny of toothed whales and dolphins. These data demonstrate that river dolphins, beaked whales and ocean dolphins diverged after sperm whales. Dolphins and beaked whales have some morphological similarities with sperm whales. They are deep – diving behavior and suction - feeding. Their similarities also involve scull complexes that are of significant value, namely the pterygoid sinuses and ear bones. Further radiation of the cetacean involved radical changes in feeding strategies, evolution of filter-feeding. These changes were connected with changing oceanic food chains, climate, circulation, productivity. And dolphins began differ in biology from their neighboring clades of sperm and beaked whales.

Tests of adaptation.

I would like to distinguish two very important traits that represent dolphins’ adaptation and concern such categories as behavioral and morphological ones.

Speaking of behavioral category, I would like to mention that dolphins lead a gregarious way of life. They live in groups of various sizes. It considerably increases their opportunities of surviving, gives them more opportunities of finding food and of defending themselves from enemies, of taking care of their children. Dolphins’ life in groups and their interaction turn to be an important factor of their adaptation.

I would propose the first part of research plan to be dedicated to this dolphins’ behavioral trait.

It will be mainly based on the method of observation that will allow us to investigate their 5 main behavior categories, namely: travelling, feeding, social, milling and human interaction.

It will give us the opportunity to define some qualities that make a dolphin be the leader of the group, to determine factors that can cause dolphins’ aggressive behavior towards each other, especially it concerns the males. We will investigate group dynamics and mechanisms of formation of effective adaptation.

The second part of our research plan will be dedicated to morphological trait such as dolphins’ acoustic vocalizations. We will investigate mechanisms of echolocation with the help of mathematics modelling. Dolphins’ sound signaling is a very significant factor of their adaptation, because it accompanies all main processes of their life and activity. It is of great value, as it plays important role in organization of dolphins’ group actions. Sound echolocation covers searching, hunting, playing, parental and other forms of dolphins’ behavior. Echolocation is a way of using sounds to find certain objects in the surroundings. Dolphins use it in the water. Echolocating, dolphins generate a sound pulse in their forehead which is sent into the water. The sound creates an echo of the objects that returns to the dolphins. Different objects give different kinds of echo and allow dolphins to judge how far the object is.