Influence of spatial and temporal factors on vocal activity of the steppe marmot, Marmota bobak
The vocal activity (number of call per minute) of Marmota bobak, provoking a sound response of animals to humans, was recorded in field conditions (Kharkov oblast, Ukraine). In order to estimate the influence of spatial and temporal factors on vocal activity of the steppe marmot, a distance from a stimulus, the current time measured in minutes, and the time of adaptation, in days were taken into account. When the distance from the stimulus increases, the vocal activity is lowered. For the first minutes it increases drastically, reaches maximum at the 4th min, and then is reduced; in several days, marmots become adapted to the stimulus. The vocal activity of marmots is suggested to be their integral response to the complex of several factors acting simultaneously. A similar vocal activity of animals is possible within a wide range of combinations of various parameters which characterize the stimulus. A graph of isolines (lines of equal vocal activity values in the coordinates "distance from stimulus-current time" is given. The function of alarm call in marmots is suggested not to give information about specific characteristics of the stimulus, but to create and keep the particular level of the alertness corresponding to the situation.