Saltatory Search in Free-Living Callithrix jacchus: Environmental and Age Influences

Abstract

Researchers generally categorize motile foraging behavior into 3 strategies: ambush, cruise, and saltatory searching. During saltatory searches, predators move from one location to the next, frequently pausing to scan for prey that are hard to detect and widely distributed. We investigated whether 1) the foraging strategy of free-living common marmosets conforms to the strategy; 2) scanning occurs solely when the individual is stationary; 3) the environment (dense and sparse vegetation) influences foraging behavior; and 4) the age of the marmosets is related to their foraging behavior. Bezerra carried out the observations in a 32-ha fragment of Atlantic Forest in the Northeast of Brazil and in an adjacent condominium. Using the focal sampling method, we observed 31 common marmosets, including adults, juveniles, and infants, Bezerra recorded the following behaviors (in dense and sparse vegetation): locomotion (subdivided into minor locomotion—moving distances ≤1 m; major locomotion—moving distances >1 m), scan, pause, and capture. The frequency of scanning behavior was significantly greater when individuals were stationary. Adults and juveniles exhibited the clearest differentiation in terms of locomotion, both adjusting the behavior in accordance with the environment; periods of major locomotion were more frequent in sparse vegetation, whereas minor locomotion was more frequent in dense vegetation. In contrast, infants exhibited major locomotion more frequently in dense vegetation. We conclude that common marmosets use a saltatory strategy when foraging, and that their foraging behavior is plastic, changing both with the age of the individual and with the density of the vegetation.