One of the current standard approaches to the study of animal welfare is measuring hypothalamic-pituitary-adrenal activity, frequently in association with behavioral assessment. We studied the effects of food-based environmental enrichment on adrenocortical activity and behavior in zoo-housed collared anteaters (Tamandua tetradactyla; n = 5). We successfully validated measurements of fecal cortisol metabolites (FCMs) using an 11-oxoetiocholanolone enzyme immunoassay by stimulating (ACTH injection) and suppressing (dexamethasone administration) adrenocortical activity. Three months later, we subjected animals to an ABA-type experiment (three 6-week periods): pre-enrichment (routine diet: A), enrichment (modified diet: B), and post-enrichment (routine diet: A) periods. We assessed adrenocortical activity by collecting individual feces three times a week (total number of samples: 228), and evaluated behavior by performing 3 days of behavioral observations per period (with a total of 3,600 behavioral data points for the individuals studied). Statistical analysis revealed changes in FCM concentrations (µg/g) over the periods (3.04 ± 0.68, 2.98 ± 0.66, and 4.04 ± 0.90, respectively). Additionally, it showed that the number of FCM peaks was highly reduced during enrichment; meanwhile active natural behaviors were significantly increased. We consider that these changes in response to food-based environmental enrichment improved the welfare of individual zoo-housed collared anteaters. This research might contribute to in situ and ex situ studies on the physiology and behavior of this endemic South American species.

We characterized behavioral and adrenocortical activities of Tamandua tetradactyla under human care driven by the hypothesis that they vary between males and females. We also assessed the potential association between natural or abnormal behaviors and adrenocortical activity. We kept females and males T. tetradactyla in individual, contiguous enclosures at Córdoba Zoo (Argentina), under natural photoperiod and temperature. During 29 consecutive days we monitored the animals’ behavior by recording their activity pattern every 5 min using infrared cameras (8352 records/individual). We collected all feces and measured fecal glucocorticoid metabolites (FGM) with an 11‐oxoaetiocholanolone enzyme immunoassay. We found individual differences in all behavioral variables. We detected that females exhibited lower total activity than males (23.8 ± 0.2% and 32.3 ± 0.3%, respectively; p = .005). Females were more active at night and males during the day (p < .05) and exhibited less abnormal behaviors than males (p = .05). Although we did not find sex‐related differences for average FGM, we detected individual differences (p < .0001). We found that daily FGM showed negative (−0.39) and positive (0.38) correlations with natural and abnormal behaviors, respectively (p < .0001). Thus, we consider that individual input and sex are factors to be considered in stress responses of the species in captivity. Natural and abnormal behaviors may demand different levels of adrenocortical activity. Our findings may prove useful as normative data for ex situ management of conservation programs.

Management procedures affect behavioural and physiological stress responses of wild mammals under human care. According to the Reactive Scope Model, normal values are presumed to exist within predictive and reactive ranges. First, stress parameters of zoo-housed adult Tamandua tetradactyla were evaluated in winter and summer (29 days each), determining the level of behaviour and/or physiological parameters needed to respond to predictable environmental changes. Secondly, the effects of veterinary procedures and transportation were studied in both seasons. Non-invasive methods were applied, assessing behaviour through videos and adrenocortical activity by faecal glucocorticoid metabolites (FGMs). Lesser anteaters exhibited seasonality (summer > winter) in some behavioural parameters, such as nocturnal activities, as well as in the activity cycle (e.g., acrophase) and FGMs. A veterinary check elicited an increase in total activity (TA), natural behaviours and repetitive locomotion and affected the activity cycle, particularly in summer. Transport produced changes in TA, nocturnal and natural activity and some variables of the activity cycle, mostly during summer. Although the effects of routine management procedures were different from each other and presumably stressful, they elicited changes only at the behavioural level, which was greater during summer. The differences observed according to non-invasive methodologies highlight the importance of a multidisciplinary approach in this context and suggest that it is unlikely that individual welfare was affected.