Effects of Rearing on the Behaviour of Zoo-Housed Chimpanzees (Pan troglodytes).

Early-life experiences may considerably affect the behavioural patterns of adult primates. Particularly, atypical rearing practices might lead to abnormal behaviours and social-sexual deficiencies in captive, adult non-human primates. We conducted behavioural observations of mother-reared (n = 5) and hand-reared (n = 6) adult chimpanzees in a social group at Parco Natura Viva, Italy. We used continuous focal animal sampling to collect behavioural data focusing on individual and social behaviours. We found that all study subjects performed individual and social species-specific behaviours. However, mother-reared chimpanzees performed locomotion and affiliative behaviours significantly more than hand-reared subjects. In addition to these species-typical behaviours, hand-reared chimpanzees showed significantly more abnormal behaviours than mother-reared subjects. Therefore, these findings suggest that hand-rearing could have wide-reaching effects on the behavioural repertoire in adult zoo-housed chimpanzees. Hence, even if sometimes human intervention in rearing may be necessary to ensure the survival of captive infant chimpanzees, our results suggest that zoo-housed chimpanzees might benefit from minimised human-animal interactions and exposure to conspecifics throughout their development. These suggestions should be implemented in regular husbandry practices.

Abnormal mare behaviour is rarely associated with changes in hormonal markers of granulosa cell tumours: A retrospective study.

BACKGROUND: Abnormal or undesired mare behaviours are often assumed to be associated with ovarian abnormalities. OBJECTIVES: We aimed to determine the incidence of abnormal behaviours and their association with concentrations of one or more ovarian hormones associated with a granulosa cell tumour (GCT). STUDY DESIGN: Retrospective descriptive. METHODS: A total of 2914 hormonal profile samples submitted with the words behave, behaviour, or behaving in the submission history were analysed. The association between reported abnormal behaviours and concentrations of testosterone, anti-Müllerian hormone (AMH), inhibins and inhibin-B were assessed. Statistical analysis was performed using a Chi-squared test of association. RESULTS: Of the 2914 cases that were submitted due to behaviour issues, 2506 (86%) did not have any of the measured hormones reach GCT-like concentrations. The remaining 408 cases had either one (63%), two (25.5%), or three (11.5%) hormones with concentrations consistent with those from confirmed GCT cases. Testosterone had the lowest percent of GCT-like values among the cases (7.7%), compared with AMH (9.4%), inhibins (9.6%) and inhibin B (8.7%). Stallion-like behaviour was significantly associated with increased concentrations of all four hormones. In contrast, aggression, oestrous and other abnormal behaviours were significantly less likely to be associated with increased concentrations of the hormones. MAIN LIMITATIONS: Retrospective study, using sample submission history. CONCLUSION: Overall, the abnormal behaviours among mares, except the stallion-like behaviour, were not associated with increased ovarian hormones. These results highlight the common misassumption about the involvement of the ovaries in 'abnormal behaviours' or 'undesirable behaviours' of mares.