Want to Save a Cow From Being Attacked By a Predator? Paint Some Eyes on Its Butt

In terms of the food chain, cows don't rank very high. In Botswana, top predators like lions and leopards take regular bovine meals, frustrating farmers and prompting them to take aim at lions to try to protect their cattle herds.

There may be a better way. It involves painting a pair of eyes on the cows' rear ends.

That’s according to a new study published in Communications Biology, which demonstrated that cows sporting the confusing paint job stood a better chance of staying alive. To test the theory, a team of researchers led by ecologist Neil Jordan of the University of New South Wales in Sydney, Australia, and Taronga Western Plains Zoo recruited 2061 cows in Botswana between 2015 and 2018 and split them into three groups. A test group of 683 cows had eyes painted on their butts, while 543 cows had cross marks, and the remaining control group of 835 was left unmarked.

Incredibly, none of the cows with the eyes were killed by predators. The group with cross marks saw four deaths, and the control group 15 deaths, mostly from lion attacks.

Why did the eyes prove to be a deterrent? Lions are ambush predators, preferring stealth to sneak up on their prey. If they believe they’re being spotted by the “eyes” on the cow’s rear end, they’ll choose to wait for a more inviting target. It’s a defense seen elsewhere in nature, where butterflies, fish, and birds have “eyes” that discourage predators. (It works with humans, too. In a 2012 study, signs placed near bike racks that featured a pair of eyes reduced theft.)

Researchers aren’t sure what would happen if all cows had a second pair of eyes. The groups in the study were mixed together, and it’s possible the predators who pounced on the unmarked cows might just go ahead and attack the painted cows if there were no other options in front of them. They might also learn about the misdirection over time. But at present, this simple and inexpensive trick might prove useful for farmers looking to outwit their predatory neighbors.

[h/t Smithsonian]