Synchronous breathing by pilot whales

When two or more animals behave synchronously, then, unless they are both independently responding to some external stimulus, they are attempting tomatch to each other’s behavior, or at least one is trying tomatch the other’s behavior. Synchrony can thus be a particularly clear example of integrative behavior (Whitehead 2008), and so synchronous behavior can be used to indicate affiliative relationships among individuals and thus to buildmodels of social structure. Synchrony has been described in a range of animal groups, including odontocete cetaceans (Norris and Dohl 1980, Heimlich-Boran 1988, Whitehead 1996, Mann and Smuts 1999, Hastie et al. 2003, Connor et al. 2006, Perelberg and Schuster 2008, Sakai et al. 2009). Synchrony has been defined in two principal ways: a nonrandom, overly clustered, temporal distribution of behavior among members of a group (Whitehead 1996, Hastie et al. 2003), and simultaneous behavior by individual groupmembers (Connor et al. 2006). As no two actions are actually absolutely simultaneous, these two definitions are not completely distinct. Rather their usage reflects different research emphases. In the first the degree of temporal synchrony is measured and analyzed (e.g., Hastie et al. 2003), whereas in the second the temporal matching is assumed and data collection concentrates on issues such as the identities of the participants and their social and environmental circumstances (e.g., Connor et al. 2006). Both types of study give insight into the function of synchronous behavior. In cetaceans, as well as in other animals, a range of functions have been suggested for synchronous behavior. These include a signal for cooperation or to reduce tension (Connor et al. 2006), which may be more manifested at times of stress (e.g., Hastie et al. 2003). Rather more prosaically, synchrony may be an artifact of swimming in close proximity, commencing a cyclical behavioral sequence at the same time (Whitehead 1996), or a method of reducing hydrodynamic drag (Weihs 2004). In bottlenose dolphins (Tursiops spp.), the cetaceans for which synchrony has been most studied, synchrony is sometimes seen as being involved with the advertisement or reinforcement of social bonds (Connor et al. 2006, Perelberg and Schuster 2008, Sakai et al. 2009).