Ecological bioacoustics of mammals is discussed as a part of population ecology. In the life cycle of species when a population is under transition from one functional state to another, the dynamics of sound activity of the animals correlates with the dynamics of other population parameters, such as the demographic and spatial pattern of the population, hormone status and various forms of activity of mammals. Ecological parallelisms in animals are accompanied by parallelisms of sound activity. Ecological types of mammal sounds are designated. The main trend of specialization in animal acoustic communication is remoteness - increase of the distance between partners. In evolution this trend results in the formation of the most specialized types of acoustic communication (for example, acoustic marking of the individual range) and to development of those transmissive features of the sounds which promote their noise immunity.