Pomerantz, O., Nyandwi, S., Baker, K., 2018. Providing feeding enrichment by hand mitigates anxiety among laboratory-housed rhesus macaques (Macaca mulatta). American Journal of Primatology 80(S1), 20 (40th Meeting of the American Society of Primatologists Scientific Program, Abstract #26).
Some husbandry procedures may be perceived as aversive by cage‐housed rhesus macaques. We assessed whether providing feeding enrichment by hand as opposed to placing it on a caging surface decreases anxiety responses to daily husbandry activities. Eleven adult males and 53 adult females housed at the Tulane National Primate Research Center were randomly assigned to one of two groups: thirty‐eight were provided the opportunity to take feeding enrichment from the experimenter's hand, and 26, designated as controls, retrieved food from a surface attached to their caging. All animals received this feeding enrichment three times weekly. Levels of anxiety‐related behaviors during room sanitation were measured using focal one‐zero sampling. Trials were conducted at baseline and monthly during the three months of treatment. Preliminary results of a mixed model ANOVA, controlling for sex, found significantly lower anxiety levels among the hand‐fed group (p=.007), and a trend towards an interaction between time point and group (p=.079). These results were driven by a monthly trial before which the control group experienced a stressful husbandry event that does not occur daily. Such events did not result in increased anxiety in the treatment group. Hand feeding may be an effective tool to reduce anxiety during husbandry activities, potentially by improving animals’ perception of caretakers and thereby providing a buffer against stressful events.