Integrating Measures of Fecal Glucocorticoid Metabolites and Giving-Up Densities to Assess Adrenocortical Activity and Well-Being in Zoo-Housed Three-Banded Armadillos (Tolypeutes matacus)

SIMPLE SUMMARY: To understand how zoo animals perceive their environment, managers evaluate their stress response through behavioral and glucocorticoid analyses. Here, we measured how seven, zoo-housed (Lincoln Park Zoo, Chicago, IL, USA) southern three-banded armadillos (Tolypeutes matacus) perceived their habitats using non-invasive sampling of both physiological (via fecal glucocorticoid metabolites, FGMs) and psychological (via foraging behavior) indicators. We offered them depletable food patches with various patch and environmental modifications. Food remaining in a patch represents the animal’s giving-up density (GUD). High GUDs are a response to increased risk; the animal does not feel comfortable and safe to forage. Before, during, and after foraging experiments, feces was collected to examine FGMs. We found that there was no relationship between GUDs and FGMs. However, results varied greatly among individuals, and each individual’s results remained consistent across experiments. Armadillos did not respond to patch modifications but did forage more when the cover substrate was increased. When species do not have dynamic and variable behaviors, as is the case with this species, the evaluation of their perception of the environment can be difficult. For this reason, GUDs and FGMs are practical to offer zoo-housed animals, provide valuable information for zoo managers on husbandry modifications and serve as enrichment for the animal. ABSTRACT: To monitor adrenocortical activity in zoo-housed species, we propose using physiological and behavioral indicators that are non-invasive and practical to implement. We explore this model in the southern three-banded armadillo (Tolypeutes matacus; armadillo), which is a near-threatened species commonly found in zoos. We aimed to (1) deploy food patches to quantify foraging behavior (via giving-up densities, GUDs); (2) determine the effects of food patch and environmental modifications on individuals’ GUDs and adrenocortical activity (via fecal glucocorticoid metabolites, FGMs); and (3) examine the relationship between GUDs and FGMs. Three males and four females received food patches under varying experimental conditions at the Lincoln Park Zoo (Chicago, IL, USA). Fecal samples were collected before, during, and after foraging experiments to examine FGMs. Armadillos did not respond to patch modifications but did forage more when given increased cover. Individual mean FGMs and GUDs were highly variable, and individuals had consistent FGM and GUD ranks across experiments. FGMs and GUDs did not vary across the experiments nor did they relate to each other. Armadillos and species with a limited behavioral repertoire (i.e., constant movement) can benefit from this multi-trait model to determine the effect of environmental modifications on individuals and provide meaningful information about adrenocortical activity.