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Cattle herds in Botswana’s Okavango Delta region are plagued by attacks from lions and other predators, prompting farmers to retaliate by killing predators. Another non-lethal technique involves painting eyes on cattle butts to trick ambush predators like lions into believing they have been spotted by their intended prey. It’s called the “Eye-Cow Project” and a recent article published in the journal Communications Biology provides strong empirical evidence for this practice. There are now how-to guides for using the eye-cow technique available in English and Setswana, so that farmers can try it out for themselves.
Neil Jordan, a conservation biologist at the University of New South Wales in Australia, came up with the idea several years ago while doing fieldwork in Botswana. Local farmers killed a pair of lionesses in retaliation for attacking their herds of cattle, and Jordan wanted to find a non-lethal alternative. The African lion population has fallen dramatically from over 100,000 in the 1990s to somewhere between 23,000 and 39,000 in 2016, largely due to retaliatory killings.
Jordan knew that butterfly wings sporting eye-like patterns are known to ward off birds of prey and are also found in some fish, mollusks, amphibians and birds, although such patterns have not been seen in mammals. He also discovered that Indian forest loggers are known to wear masks on the back of their heads to discourage tigers from hunting their prey. He had seen a lion stalking an impala and noticed that the predator had given up hunting when the prey spotted him. Lions are ambush hunters, reasoned Jordan, and decided to test his “detection hypothesis” that painting eyes on cow butts would deter predatory behavior from the local lion population.
The Botswana Predator Conservation Trust (BPCT) agreed to work with Jordan on the project, along with a local farmer, for a ten week pilot study. Jordan and the farmer painted eyes on a third of a herd of 62 cattle, and did a count when the cattle returned to the barn each night to see how many had survived. Only three cows were killed during this period, none of which had painted eyes on their buttocks. All the painted cows survived.
While the sample size was small, these results were encouraging enough to convince Jordan to conduct a more ambitious study over the past four years. His team worked with local farmers in the Okavango Delta region, combing the cattle of 14 herds (a total of 2,061 animals). They used acrylic paint (black and white or yellow), applied with foam stencils in the shapes of the inner and outer “eye”. The colors were chosen “because of their high contrast and aposematic characteristics, common in natural anti-predator signaling settings,” the authors wrote.
About one third of the cattle in each herd had eye patterns, one third had simple cross marks, and one third were not painted at all. The results confirmed Jordan’s preliminary findings. Cattle with eyes painted on the rump were much more likely to survive than cattle that had crosses painted on their buttocks and those that weren’t painted at all. But the authors were surprised to find that even painted crosses offered some survival advantage over unpainted cattle. During the four-year study, 15 unpainted cattle (out of 835) and four cross-painted cattle (out of 543) were killed by lions; none of the 683 cattle with painted eyes were killed.
“To our knowledge, our research is the first time eye spots have deterred large predatory mammals,” said co-author Cameron Radford, a graduate student at the University of South Wales. “Previous work on mammalian responses to eye patterns has generally supported the detection hypothesis. We believe this may suggest the presence of an inherent eye response that could be exploited to modify behavior in practical situations, for example to prevent human-wildlife conflict and reduce criminal activity in humans.
There are a few caveats. First, Jordan acknowledged that there were always unmarked cattle in the herd for their witness experiences – what he called “proverbial sacrificial lambs”. It is not clear if applying painted eyes to cow butts would be as effective if all the cows in the herd were painted. He suggests that farmers apply the ratings to the most valuable cattle in the herd as the best approach until further research can be done. Second, there is the issue of habituation: whether predators will eventually get used to painted eyes and learn to ignore it as a deterrent.
“Protecting livestock from wild carnivores – and carnivores themselves – is an important and complex issue that likely requires the application of a range of tools, including practical and social interventions,” Jordan said. “The cow eye technique is one of the many tools that can prevent carnivore-livestock conflict. No tool is likely to be a quick fix. Indeed, we must do much better than a quick fix if we are to ensure the successful coexistence of livestock and large carnivores. But we hope this simple, inexpensive and non-lethal approach could lower coexistence costs for the farmers who bear the most. “
DOI: Communications Biology, 2020. 10.1038 / s42003-020-01156-0 (About DOIs).
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