In an effort to determine the function of a low intensity repetitive call termed chuffing, quantitative data were analyzed for behavioural associations and contingencies, and several hypotheses were tested regarding variable call structure. Adult bears of both sexes chuff in a variety of circumstances, but the call is heard predominantly in maternal females during early stages of cub development. In the maternal situation it is most often emitted during simple behavioural changes, and with the exception of promoting mother-cub contact it evokes no specific response. Differences in call duration do not signal qualitative or quantitative differences in the mother's behaviour, nor do they evoke different responses from the cubs. Neither distance nor visibility of the cub affects the number of sound elements composing the call. The physical structure of the call suggests its source potentially can be localized with regard to both direction and distance.