Social Behaviour, Vocalization and Conservation of Narwhals

of social species. Group living improves resource acquisition (Creel and Creel, 1995), vigilance, and defence against predators (e.g., Bertram, 1980), as well as enhancing the care of the offspring (Clutton-Brock, 2002). In some species, such as African elephants (Loxodonta africana; Wittemyeret al., 2005) and resident killer whales (Orcinus orca; Bigg et al., 1990), individuals form permanent groups that they keep for their entire life. Groups can differ in behaviours that affect their fitness, such as their food preferences and hunting techniques, or in the use of tools (Whiten et al., 1999). In some groups, older individuals possess ecological knowledge that they share only with the rest of their group, which gives fitness advantages to the members of that group (Payne, 2003). Thus, group membership may ultimately affect individual survival. Communication is crucial to all social species. Communication helps to synchronize the behaviour of members of a group and allows for individual or group recognition or both. Individual recognition through vocal signatures is a widespread form of social communication among mammals (e.g., Goldman et al., 1995) and may be used as contact calls to keep group cohesion in fluid fusion-fission groups (e.g., Connor et al., 2000). Group-specific calls are common in social marine mammals whose individuals