Low budget zoos and circuses have been known to paint stripes on donkeys and horses and claim these are zebras. It turns out the painted animals may benefit from this practice.
Japanese scientists recently discovered that painting white stripes on black cows deterred biting flies. They compared the incidence of flies landing on the striped cows compared to black cows painted with black stripes (to see if the paint alone had an effect) and unpainted black cows. The striped cows had half as many flies landing on their legs, and around a third as many flies landing on their bodies.
This doesn’t mean, however, that Belted Galloways will have fewer fly bites than solid white or black cows. Thick stripes are far less effective. Flies avoid landing on animals and surfaces with stripes with a maximum width of 5 cm (2 inches) or dots with a maximum diameter of 10 cm (4 inches). The theory is that the stripes somehow confuse the flies just before landing.
The researchers suggest that livestock can be painted with stripes using paint that is now being used to mark livestock for other purposes (such as indicating animals that have received a veterinary treatment, or animals that have been bred). This paint doesn’t last more than a month or two but can be used during peak fly seasons.
Source: Kojima, T., K. Oishi, Y. Matsubara, Y. Uchiyama, Y. Fukushima, et al. Cows painted with zebra-like striping can avoid biting fly attack. PLoS ONE. 2019. Volume 14. Issue 10: e0223447.
— Janet Wallace