Ontogenetic Changes in Feeding Behaviors in Tufted Capuchins

Objectives

Wild juvenile capuchins exhibit lower feeding success than adults, particularly for mechanically challenging foods, but ontogenetic changes in oral food processing behaviors related to this reduced success are unknown. We test how oral food processing efficiency varies across development in an experimental setting in tufted capuchins (Sapajus spp.). Further, we simulate discontinuous feeding observations to test the comparability of behaviors measured in wild and captive settings.

Materials and Methods

Twenty-nine captive and semi-wild infants (n = 2), juveniles (n = 12), older juveniles (n = 4), and subadults-adults (n = 11) were video recorded while feeding at the Núcleo de Procriação de Macacos-Prego Research Center (Araçatuba, Brazil). Each animal was offered a series of five foods ranging in volume, toughness, and elastic modulus.

Results

Measures of oral food processing inconsistently varied with sex; however, younger animals were less efficient in food processing than older individuals. Larger and more mechanically challenging foods were associated with longer feeding sequence durations and an increased frequency of anterior ingestion, posterior ingestion, and chewing during a feeding sequence. Simulated discontinuous data from the first and last halves of the feeding sequences closely replicated continuous results.

Conclusions

Our results indicate younger capuchins have reduced oral food processing efficiency compared to adults through increased duration, behavioral frequencies, number of chews, and behavioral patterns. Further, our continuous and discontinuous comparisons support the use of discontinuous feeding behaviors from the first and last halves of the feeding sequence. We caution that researchers should be careful to capture infrequent behaviors when using discontinuous data.