ETD

• Coprophagy
• Echinococcus equinus
• Lion faeces
• parasite transmission
• Plains zebra
• social facilitation

Cystic echinococcosis caused by Echinococcus equinus is globally distributed. In Etosha National Park (ENP), a unique sylvatic cycle occurs among lions, jackals, and plains zebras. Given the unexpectedly high prevalence of infection in zebras despite harsh environmental conditions that limit egg survival, we tested the hypothesis that direct interactions with lion faeces might represent a potential exposure route. Across two sampling periods (September 2023 and September 2024), lion faeces were placed along zebra trails and monitored with 32 camera traps for 193 trap-days. From 2,376 video recordings, no coprophagy by zebras was observed. However, zebras were the herbivore species that most frequently investigated faecal samples, showing the highest rate of sniffing. A GLMM revealed that sniffing probability was higher in zebras compared to other ungulates and specifically declined sharply with faecal age, indicating heightened interest during the first hours after deposition, when egg viability is expected to be greatest. In addition, finer-scale social dynamics emerged within zebra events: the likelihood of sniffing increased with the cumulative number of preceding sniffers and with the intensity of the previous sniff.
Overall, while coprophagy by zebras appears unlikely, frequent close-range investigation of lion faeces, enhanced by social facilitation within groups, may represent a non-negligible behavioural pathway contributing to E. equinus exposure in ENP.
Lastly, carnivore observations documented coprophagy in jackals, spotted and brown hyenas, and lions, highlighting potential roles in either reducing or dispersing infective material and thus influencing local Echinococcus transmission processes.