Japanese researchers painted black-and-white stripes on six black cows, and biting flies landed on them about half as often. The striped cows also spent less time stamping, flicking their tails, and throwing their heads to drive flies away.
The study, led by Tomoki Kojima of the Aichi Agricultural Research Center with colleagues from Kyoto University, appeared in PLOS ONE in 2019. It won the 2025 Ig Nobel Prize in Biology. The playful idea has a serious goal: protecting cattle without relying on insecticides that flies keep evolving to resist.
