Are crop fields pharmacies for megaherbivores? From ecophysiological studies of elephant (Loxodonta cyclotis) crop raiders in Gabon

Abstract

1. Damage to crops is a major cause of human-elephant conflict (HEC) in elephant range states. Elephant crop raiding drives farmers’ resentment against elephants and reduces local community support for wildlife conservation. While elephant crop raiding ecology is well studied, further investigations on HEC mitigation strategies are still needed. Thus, there is a need to focus on less investigated areas, such as the physiological drivers of elephant crop-raiding behaviour, using multidisciplinary sciences.
2. Two physiological proxies, gastrointestinal parasite infestations (GPI) and faecal glucocorticoid metabolite (fGCM) concentrations, common in animal ecophysiology, were used to help understand differences or motivations in the preferences of crops by elephant raiders.
3. The results show, for the first time, that forest elephants may increase the frequency of crop raiding according to GPI, indicating a self-medication behaviour. Increases in parasitism prevalence (PP) and parasitism intensity (PI) in sampled boluses led to 28% and 0.16% more intakes of all crops, respectively. Parasitism prevalence (PP) increases in elephant boluses also led to 16% and 25% more bananas and papaya intakes, respectively, while PI increases in boluses led to 0.1% more intakes of both bananas and papaya plants. No such predictions were found for other crops (cassava and palm plant), nor for natural food species intakes. Furthermore, fGCM concentrations were not related to elephant crop raiding. Results highlight a trade-off between the benefit of elephants raiding crops and the danger of encountering farmers by adopting nocturnal crop-raiding behaviours.
4. Practical implication. We propose that elephants may choose specific plant parts while raiding crops as a self-medication behaviour. We further discuss the importance of forest elephant conservation as they are not only forest engineers but also appear to be self-medication specialists, which could possibly help humans cope with present and future health issues. Further understanding of that self-medication behaviour can help communities cohabiting with forest elephants to focus on the broader health benefits rather than solely on the immediate issue of crop damage.

Citation

Ngama, S., Bindelle, J., Brown, J. L., Poulsen, J. R., Hornick, J. L., Linden, A., ... & Vermeulen, C. (2025). Are crop fields pharmacies for megaherbivores? From ecophysiological studies of elephant (Loxodonta cyclotis) crop raiders in Gabon. Ecological Solutions and Evidence, 6(4), e70141. https://doi.org/10.1002/2688-8319.70141