Anthropogenic risk increases night-time activities and associations in African elephants (Loxodonta africana) in the Ruaha-Rungwa ecosystem, Tanzania

Elephants face diverse threats from human activities and use temporal and social strategies to reduce human-induced mortality risk. We used data from camera trap surveys in 2018-2019 (n = 1625 independent detection events from 11,751 sampling days) to investigate elephant responses to anthropogenic risk in the Ruaha-Rungwa ecosystem, Tanzania. The study was conducted in one low-risk and three high-risk sites using 26-40 paired camera trap stations per site. Risk influenced the active periods, use of roads and water sources, social associations and behaviour of elephants. Elephants demonstrated significantly more night-time and reduced daytime activity in the high-risk sites relative to the low-risk site. This higher night-time activity in the high-risk sites was observed for both males and females, though it was more pronounced for cow-calf groups than lone males. Foraging events and use of water sources were more frequent at night in the high-risk sites. Elephants used roads as movement routes in the low-risk site but avoided roads in the high-risk sites. Males were significantly more likely to associate with other males and cow-calf groups in the high-risk sites. Fewer occurrences of relaxed behaviours were observed in the high-risk sites compared to the low-risk site. We discuss the potential implications of our findings for elephant survival and reproduction.