In 2019, a team of Japanese scientists at the Aichi Agricultural Research Center in Nagakute undertook a bold experiment: they painted six Japanese black cows in zebra‑like stripes.
What motivated this unusual approach? The answer lies in the persistent problem of biting flies. These insects feed on livestock blood, causing painful swelling, weight loss, and in severe cases, disease spread or death. Traditional control methods rely on chemical pesticides applied directly to animals, which raise significant environmental concerns.
Observing that zebra stripes are thought to deter biting flies, the researchers hypothesised that mimicking this pattern on cattle could reduce fly landings. They tested the idea by applying three conditions to the six cows: their natural all‑black coat (control), an all‑black stripe pattern, and a black‑and‑white stripe pattern that mimics a zebra.
Paints were waterborne lacquers designed to be safe for the animals. Results, published in PLOS One, showed that cows painted in zebra‑like black‑and‑white stripes experienced a 50% reduction in fly landings compared to both the natural and all‑black stripe groups. Additionally, the zebra‑striped cows displayed noticeably fewer fly‑repelling behaviours such as stomping, tail flicking and head shaking, indicating greater comfort.
Researchers explain that flies have compound eyes that process visual information quickly but at a lower resolution than human eyes. The alternating black and white bands create an optical illusion that makes the animal appear to be in motion, confusing the fly’s landing reflex. Similar experiments have shown that zebra‑stripe patterns can repel flies on stationary objects, but this is the first time the concept was applied to livestock.
These findings suggest that painting livestock in zebra‑like stripes could be a practical, eco‑friendly alternative to chemical fly control.
