CONICET | Buscador de Institutos y Recursos Humanos

The study of daily physiological and behavioural patterns in controlled conditions through non-invasive techniques is a first step to understand how animals respond to anthropogenic disturbances. In this study, adrenocortical and behavioural activities of adult lesser anteaters (Tamandua tetradactyla; 3 males, 3 females) from Cordoba Zoo, Argentina were characterised during 29 consecutive days of autumn 2016 (April 21-May 20). Animals were housed in individual and contiguous enclosures, under natural photoperiod and temperature; and fed with a balanced diet and food-based environmental enrichment. All faeces were collected and faecal glucocorticoid metabolites (FGM) were measured with an 11-oxoaetiocholanolone EIA. Activity pattern was monitored continuously using infrared cameras, sampling behaviour every 5 minutes (8640 registers/individual). Average FGM (µg/g faeces; mean±SEM) was 3.1±0.2; with individual (P<0.0001) and sex related differences (males: 3.7±0.3; females: 2.5±0.2; P<0.05). Regarding behaviour, total activity (mean±SEM) indicated that animals were active 28.6±0.2% of the day, showing significant differences between males and females (32.8±0.3 and 24.3±0.2%, respectively; P<0.0001). Moreover, activity profiles throughout the day were dissimilar, with males being more active at day-dusk and females at dusk-night. According to Spearman?s correlation index, daily FGM and activity were correlated by r=0.19 (P<0.01). Additionally, FGM showed correlations of r=-0.39 and r=0.38 with natural behaviours and repetitive locomotion, respectively (P<0.0001). Results reveal a sexual dimorphism in adrenocortical and behavioural activity, which may indicate that sex is an intrinsic factor modulating these variables. Furthermore, increased adrenocortical activity could be an indicator of an imbalance in activity patterns towards unnatural behaviours.