Behavioural and Glucocorticoid Responses of a Captive Group of Spider Monkeys to Short-Term Variation in Food Presentation

Abstract

The presentation of food may affect feeding competition and the well-being of captive social species. We hypothesized that feeding competition in a captive group of 5 black-handed spider monkeys (Ateles geoffroyi) should increase in response to certain food presentations in terms of size, distribution and quality of food, and that higher feeding competition should lead to an increase in agonism and physiological stress (measured by faecal glucocorticoid metabolites, FGCM) as well as to a decrease in affiliation, proximity among individuals and feeding activity. We used 5 experimental treatments representing different combinations of size, distribution and quality of food. We observed social interactions for 100 h, collected 6,500 proximity and feeding activity records, and gathered 226 faecal samples. When food was clumped, individuals spent less time feeding, and there was also significant individual variation in feeding activity within treatments. FGCM levels were higher when food was clumped. These results are probably linked to an increase in feeding competition when food is concentrated. At least in small groups of spider monkeys, dispersing food in two feeding stations may be sufficient to decrease differences among individuals in priority of access to food resources, hence reducing physiological stress and interindividual differences in feeding activity.

Analytical and biological validation of a noninvasive measurement of glucocorticoid metabolites in feces of Geoffroy's spider monkeys (Ateles geoffroyi)

“…The females remained in the indoor enclosure for 2 more days to monitor their recovery from anesthesia and conclude fecal sample collection (October 20 and 21, 2020; Table 1). We expected this timeframe to be sufficient to document a substantial fGCM increase and likely also a decrease of GC concentrations based on previous work in this species (Rangel‐Negrín et al, 2009, 2015; Rodrigues et al, 2015).…”

Long‐lasting behavioral and neuroendocrine changes provoked in rabbits by cancelling a single nursing bout in early lactation

“…Each of these eight subgroups contained four animals; total = 16 males and 16 females. Cortisol levels in all samples were measured, as reported earlier (Rangel‐Negrín et al, ), using a commercial radioimmunoassay 125 I cortisol kit (Izotop; Institute of Isotopes Ltd., Budapest, Hungary; sensitivity = 2.9 nmol/L; calibration range = 0–1,600 nmol/L) and a gamma counter (Cobra Model E5005, Packard Inc., Downers Grove, IL). The manufacturer reports low cross‐reactivity with corticosterone (4.3%).…”