Vïrajenie al'trouizma stepnym sourkom. Posredstvom preduprejlaïoutsego ob opasnosti signala [Expression de l'altruisme chez la bobak grâce au cri d'alarme. Expression of altruism in steppe marmot by mean of alarm call].

Résumé

The observations were carried out on steppe marmot (M. bobac), ground squirrel (Citellus pygmaeus) and pika (Ochotona daurica) in the field. These animals utter alarm call when they detect potential danger, in our case- appoaching of the observer. We found out that alarm call is elicited not only by direct danger to the specimen but by danger to the neighbours also. It is often observed that the marmot emits alarm call when observer approach to another animal at the distance 5-20 m. The most expressive and loud notes were elicited by marmots neighbouring those which were going into a burrow in case of danger. We classified this behavior of marmots as an expression of altruism by mean of sound signal. Probably not only the production of sound is informative but also the variability of its acoustic characteristics. In this case the basic type of situation changes is the same as in case of alarm call at direct danger. The expressiveness of signals is increased by means of increasing frequency of situational changes some cases changes characteristic of frequency modulation. This phenomenon may increase expressiveness of notes too. It will be interesting to reveal whether genetic relations between animals affect this expression of altruism or not.