For more than 10,000 years, ever since man started herding cattle for food and enrichment in Africa, lions have been a huge problem.
A lion, or, more likely, a pride of lionesses - who are the real hunters - can ruin a small farmer's livelihood by killing even a single cow, especially one that is pregnant or producing milk.
Thanks to Botswana's excellent conservation policies, the country has one of Africa's largest wild lion populations - estimated at 3,000.
Recent dry weather in southern Africa however is shrinking wildlife protection areas, while farmers are forced to seek new grazing lands. As a result, lions are increasingly coming into contact with humans.
Richer commercial ranchers can erect fences to try to keep them at bay.
For poorer subsistence farmers, though, it is harder. At night they herd their livestock into stockades made of logs and thorn trees to deter the lions. They also rely on barking dogs and perhaps the bravest might have once attacked lions with a spear. Some resort to shooting them or putting out poison, although hunting is illegal in Botswana.
Short of eradicating big cats, which would be unconscionable, there are few ideas being formulated to reduce the impact of their increasing presence.
However, one conservationist who has been working with the Botswana Predator Conservation Trust thinks he might have found a solution.
On a field trip, Neil Jordan watched a lion stalk an impala for 30 minutes but suddenly abandon his prey when the antelope turned and looked at the predator. This made him think that perhaps it was the eye contact that had saved the impala.
What if, he reasoned, an eye was painted on the rump of the animal? Would that have the same effect?
"I was very reluctant to share the idea at first because it does seem a bit wacky," Mr Jordan admits. "But when we ran a short trial in 2015, we got promising, but as yet inconclusive results."
In the initial study, Mr Jordan and his team painted large eyes on a third of a herd of cows on a farm on the edge of a wildlife area near Maun, in the north of the country.
The results were encouraging. Lions killed three of the 39 unpainted cows but none of the 23 painted cows was taken.
"I cheekily called our work the i-Cow project," says Mr Jordan, who is based at the University of New South Wales in Australia. "It's the opposite approach to Apple in being a low-cost, non-technological solution."
Ron Crous, who took part in the initial study needed little persuasion to get involved.
"I've been trying to farm here for the past four years and I lost a sixth of my cattle," he says.
It was slow at first, Mr Crous says, but after a while the lions realised there was a permanent supply of food in the area. "In the past eight months I have lost half of the calves born.
"Some of the local guys have had to revert to killing lions in defence of their stock," Mr Crous says. "The sad fact is that the compensation promised by the government does not cover their losses. I have always been a conservationist, so getting to work with this initiative was easy."
This year Mr Jordan is expanding the study to two other nearby cattle farms, painting half the 60-strong herds in August. Mr Jordan has also raised funds to use radio collars and GPS logging for more accurate results on the encounters between lions and cows.
The eyes are made by cutting out shapes on foam which are stuck to a wooden board. These are painted and stamped as a pair of eyes either side of the cow's tail. The paint lasts three to four weeks before it must be reapplied.
Many experts wish Mr Jordan well, but remain sceptical. Gus Mills, a southern Africa specialist in carnivore biology, says that lions are opportunists and able to exploit many conditions.
"Why would they not soon learn that the marks on a cow's backside are innocuous?" he reasons.
Kevin Richardson, a South African animal behaviourist and so-called "Lion Whisperer" has worked closely with lions for more than two decades and told the BBC: "Honestly, I think this is wishful thinking, but I'll gladly eat my words if it works.
"I'm sceptical about whether lions are that stupid to be fooled into thinking that fake eyes are real. We've performed some cognitive experiments on lions and found that they learn quickly, so you may fool them once, but not twice."
Paul Funston, Senior Lion Program Director for the global wild cat conservation organisation Panthera, largely agrees: "Lions are often wary of new things. (They) assess risk and prefer sticking to options that they perceive are relatively safer.
"Could the eyes painted on the rumps of cattle disrupt the ever-cautious lion enough to seek out an alternative? We eagerly await the research results to evaluate its effectiveness."
Mr Jordan accepts that what conservations call habituation is an issue with almost all non-lethal deterrents.
But, he says, many of the affected livestock areas do not have resident lions who would be continually exposed to the same eye patterns and thus ignore them. Only time and trials will establish if lions are indeed cleverer than we think.
Scientists like Mr Funston are deeply worried about the future of the lion, as growing human populations make increasing demands on grazing land.
The International Union for Conservation of Nature estimates that the lion population has declined by more than 40% over the last two decades. Habitat loss and killing in defence of livestock are two of the most critical reasons for this decline.
'There is a fundamental shortage of non-lethal tools for farmers to use in dealing with this human-wildlife conflict," Mr Jordan says.
"I believe we need support for creative thinking to make a difference. It may prove to be wishful thinking, but I think we need to formally test it and other non-lethal tools if we want a future for wild lions. It might not work, we're still testing it."
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