Abstract We studied barking behaviour of roe deer, Capreolus capreolus, in an area when wolves actively prey on this species, to determine the possible functions of this signal. Our data showed that males barked more frequently than females and that males barked more often during the territorial period than outside it. Undisturbed deer that barked spontaneously, before the arrival of the observer, were significantly more likely to be male than female, while both males and females showed the same likelihood to bark in response to the presence of a human observer. When barking occurs as a result of disturbance, it may act as a "pursuit-deterrent signal" rather than to warn conspecifics of potential danger. We suggest that counterbarking also acts as a pursuit-deterrent call, since audibility is reinforced by duetting, and signals to the predator that it has been detected by the pair.