The Evolution, Function, and Meaning of Marmot Alarm Communication

When strolling through your favorite habitat, it is not uncommon to hear birds or mammals emit alarm calls (Klump and Shalter, 1984), particularly if you’re strolling with a domestic predator! These striking and often easily identified vocalizations are often loud and localizable (Hurd, 1996; Wood et al., 2000) and may be directed to both predators and conspecifics. Because predators may be better able to locate a caller, emitting these calls creates an evolutionary paradox: why call if it increases the likelihood of a caller being detected by a predator and killed (Maynard Smith, 1965)? One solution to this paradox is that if, by calling, individuals save their relatives, kin selection can explain its adaptive utility (Keller and Reeve, 2002). Alarm calls are thus a system in which we can study the dynamics of altruism. Moreover, because alarm calls may be directed to conspecifics, we can study their meaning. By meaning, I refer here specifically to their information content (Halliday, 1983; Macedonia and Evans, 1993). Calls could contain potentially referential information about the specific type of predator, and/or calls could contain information about the degree of risk that the caller faces when calling (Evans, 1997; Macedonia and Evans, 1993). Alarm calling is thus a system in which we can study the evolution and adaptive utility of complex communication and referentiality—a necessary component of human language. Calls can also contain other information, such as the identity, sex, and age of the caller. Thus, alarm‐calling systems may offer us some unique insights into the adaptive significance of individuality.