VN September 2020

Vetnews | September 2020 13 Eye-catching solution Conflict between farmers and wildlife can be intense along the borders of protected areas, with many communities bearing significant costs of coexisting with wildlife. The edge of the Okavango delta in Botswana is no exception, where farmers operate small non-commercial livestock enterprises. Livestock rub shoulders with lions, leopards, spotted hyenas, cheetahs, and African wild dogs. To protect the cattle, herds (anything between about six and 100 individual cattle) are kept within predator-proof enclosures overnight. However, they generally graze unattended for most of the day, when the vast majority of predation occurs. Working with Botswana Predator Conservation and local herders, we painted cattle from 14 herds that had recently suffered lion attacks. Over four years, a total of 2,061 cattle were involved in the study. Before release from their overnight enclosure, we painted about one-third of each herd with an artificial eye-spot design on the rump, one-third with simple cross-marks, and left the remaining third of the herd unmarked. We carried out 49 painting sessions and each of these lasted for 24 days. The cattle were also collared and all foraged in the same area and moved similarly, suggesting they were exposed to similar risk. The individuals painted with artificial eye-spots were significantly more likely to survive than unpainted or cross- painted control cattle within the same herd. In fact, none of the 683 painted “eye-cows” were killed by ambush predators during the four-year study, while 15 (of 835) unpainted, and 4 (of 543) cross-painted cattle were killed. These results supported our initial hunch that creating the perception that the predator had been seen by the prey would lead it to abandon the hunt. Cattle marked with simple crosses were significantly more likely to survive than unmarked cattle from the same herd. This suggests that cross-marks were better than no marks at all, which was unexpected. From a theoretical perspective, these results are interesting. Although eye patterns are common in many animal groups, notably butterflies, fishes, amphibians, and birds, no mammals are known to have natural eye-shaped patterns that deter predation. In fact, to our knowledge, our research is the first time that eye-spots have been shown to deter large mammalian predators. Previous work on human responses to eye patterns however do generally support the detection hypothesis, perhaps suggesting the presence of an inherent response to eyes that could be exploited to modify behaviour in practical situations, such as to prevent human-wildlife conflicts, and reduce criminal activity in humans. Possible limitations First, it is important to realise that, in our experimental design, there were always unmarked cattle in the herd. Consequently, it is unclear whether painting would still be effective if these proverbial “sacrificial lambs” were not still on the menu. Further research could uncover this, but in the meantime applying artificial marks to the highest-value individuals within the herd may be most pragmatic. Second, it is important to consider habituation, meaning that predators may get used to and eventually ignore the deterrent. This is a fundamental issue for nearly all non-lethal approaches. Whether the technique remains effective in the longer term is not yet known in this case. Protecting livestock from wild carnivores – while conserving carnivores themselves – is an important and complex issue that requires the application of a suite of tools, including practical and social interventions. While adding the eye-cow technique to the carnivore-livestock conflict prevention toolbox, we note that no single tool is likely to be a silver bullet. Indeed, we must do better than a silver bullet if we are to ensure the successful coexistence of livestock and large carnivores. Nevertheless, as part of an expanding non-lethal toolkit, we hope that this simple, low-cost approach could reduce the costs of coexistence for some farmers. (Source: https://theconversation.com/) v Customised veterinary medicines to effectively address your patient’s requirements Service Centre: 0860 109 779 or pharmacist@v-tech.co.za ISO 9001:2015 Accredited Article