Resting pattern and preferences when lying down at night in a semi-captive population of African elephants

Abstract

Despite recent improvements in semi-captive African elephant habitats and husbandry, night-time behaviour patterns are still not well documented in this species. Hence, this study investigated resting behaviour when lying down, using data recorded nine African elephants maintained in semi-captivity in South Africa. A total of 111 nights were recorded over a 33-month period (2015–2018). Closed circuit television cameras were used to record the elephant’s behaviour from 17:00–07:00. Three elephants were individually penned in a boma at night while the rest of the herd could move freely between the boma and an outdoor camp. Time laying down and standing up, location, resting side, head direction, sawdust quality, weather conditions, and number of elephants present in the boma were recorded. Data were analysed using linear mixed model and Chi-square test procedures. On average ( ± SE), the elephants slept laying down for 65.64 ± 0.79 mins (1–267 mins). They laid down 3.22 ± 0.05 times per night (0−8), with an average bout length of 69.79 ± 2.65 min and switching side at a rate of 51.03%. No difference in resting duration when laying down was observed between sex, age category, resting side, head direction, whether they were penned or not, and location (P > 0.05). Elephants rested longer laying down between 01:00 and 04:00 (P < 0.0001), with a peak between 01:00 and 02:00. They also rested longer when the weather was clear as compared to overcast and rainy conditions (P < 0.0001). An intermediate freshness of sawdust also resulted in longer resting duration (P < 0.001). Furthermore, elephants laid down more when they were unpenned (P < 0.05); when the sawdust was at an intermediate freshness (P < 0.001); when the number of elephants in the boma was at an intermediate number of 4 (P < 0.001); when the weather was overcast (P < 0.001), and when the ambient temperature was mild (P < 0.001). They were observed laying down more often between 23:00 and 03:00 (P < 0.001), with mature adults preferring the areas opposite to the main entrance of the boma while the younger elephants preferred areas closer to the main entrance (P < 0.0001). Finally, high individual variations were observed in resting duration, number of bouts and average bout length. Further studies are therefore needed to investigate how preferences, personality traits, life-history and external factors associated with eco-tourism can affect the quality of resting laying down in captive African elephants.