How many words of praise are said in the history of mankind about the dog - the oldest companion of man the first of the domesticated animals! And how many at the same time attempts were made to understand, Why does the dog behave like this? and not otherwise? Alas, People, Accepting the services of a trusted friend , His vision of the world , their habits, He explained his actions in his own way. The science of animal behavior, their relationship to the environment, and to each otherethologywas born less than a hundred years ago, in the first quarter of the 20th century. Since then, scientists have learned a lot about animals in general and about dogs in particular. Despite the development of high technology, a person still can not do without the help of a dog. So, in our time, when it seems that everything that needs protection is equipped with the most complex alarm system, the demand for guard dogs, nevertheless, has not disappeared. Dogs are cheaper, working with them in some cases is easier and also more reliable. Security alarms can be triggered by a magnetic storm or because a fly has landed on it. A dog will always distinguish a real robbery attempt from random factors.