Roaring and numerical assessment in contests between groups of female lions, Panthera leo

摘要: Abstract Abstract. Theoretical and experimental studies of assessment in animal contests have, until now, focused on disputes between single individuals. However, whereas competitors usually avoid fights with opponents that are larger or stronger than themselves, social groups might be expected to adjust their agonistic behaviour according the number individuals own opposing group. This hypothesis was tested using playback experiments generate controlled artificial female lions. Recordings females roaring three chorus were played back simulate presence unfamiliar intruders within territories 21 different lion prides Serengeti National Park, Tanzania. Defending adult less likely approach playbacks a intruder occasions when they did made more cautiously. Defenders also carefully adjusted decision size composition group, attempted recruit extra companions contest by some absent at time playback. A strong selective advantage avoiding costs fighting could have led widespread evolution numerical skills species.