Rapid habituation of scan behavior in captive marmosets following brief predator encounters.

Scan behavior in 10 captive predator-naive adult black tufted-ear marmosets (Callithrix penicillata) was investigated prior, during and following brief predator encounters (taxidermized oncilla cat -- Leopardus tigrinus) versus neutral stimulus exposures (stuffed toy). For each stimulus, three 9 min home-cage trials were conducted > or = 72 h apart. Each trial was divided into three consecutive 3 min intervals: pre-exposure baseline observation, stimulus exposure, and post-exposure observation period. Post-exposure scan duration increased during the first two predator confrontations, while scan frequency increased significantly only after the first. Scan behavior remained constant within the last predator encounter, as it also did within and between the three neutral stimulus exposures. Although marmosets scanned more often and significantly longer after encountering the predator than the neutral stimulus, this response rapidly habituated by the second trial. Therefore, black tufted-ear marmosets in a familiar environment rapidly habituate to brief repeated predator encounters, possibly minimizing anti-predation costs once the degree of a potential threat has been adequately assessed.