Eavesdropping and risk assessment between lions, spotted hyenas and African Wild Dogs

Vocalizing allows rapid transmission of detailed information beyond line of sight. However, the risk of eavesdropping by unintended receivers means there is also a potential cost to any vocalization. For fugitive species such as African wild dogs the potential cost of attracting dangerous competitors as eavesdroppers is especially significant. Experiments presented here demonstrate that eavesdropping lions Panthera leo were highly motivated to approach playbacks of wild dog Lycaon pictus vocalizations. As lions will kill any wild dogs they can catch, wild dogs risk paying high costs should their calls be detected. Lions were less likely to approach playbacks of spotted hyena Crocuta crocuta whoops, with responses split according to gender: male lions remained quick to approach hyena whoops, but females without accompanying males typically did not approach. Although hyenas seemed at least as capable as lions of detecting playbacks of wild dog calls, they were significantly less likely to subsequently approach them. Analogous to female lions faced with hyenas, the reluctance of hyenas to approach wild dogs may well derive from an assessment of the potential risks involved. We consider the hypothesis that wild dog twitters display counter-adaptations against eavesdropping, but suggest that this species may best limit the risk of detection by avoiding areas where they are most likely to be overheard by lions. 2010 Blackwell Verlag GmbH.