PLoS ONE | Kojima et al.

Scientists Painted A Cow To Figure Out What A Zebra's Stripes Are For

Science doesn't always take the straightest of lines to reach a conclusion. But then, the point is to get to the truth about a thing, and if that means an odd, meandering route, then so be it.

Which is perhaps how a bunch of biologists ended up in a pasture with buckets of livestock-grade paint.

Among the many questions biologists have asked for generations is, why do zebras have stripes?

We know that a tiger's stripes help it remain unseen while it hunts through jungles and tall grasses. But zebras don't do a ton of hunting, and jungles aren't really their scene.

As for tall grasses, well, yeah, they do hang around there, but does anybody think this zebra is really blending into the background?

Unsplash | Ron Dauphin

I'm sure that in certain environments, zebras have a bit of an advantage, but as clever camouflage goes, nature has come up with much, much better than this.

The biologists' hypothesis is that a zebra's stripes serve a different, but no less important function — preventing bug bites.

Unsplash | Thomas Q

The thought is that the stripes might confuse a bug's ability to judge where and how to land, preventing them from biting.

Flies are more than just a nuisance for the cattle industry.

Bug bites are estimated to cost the U.S. cattle industry as much as $2.2 billion a year, as the animals graze less, sleep less, eat less, and get more stressed when they're harassed by flies.

Figuring out if zebra stripes do indeed prevent bites is easily a worthwhile study.

So, naturally, a team of Japanese researchers looking to confirm that idea went out into a cow pasture and painted six cows to look like zebras.

PLoS ONE | Kojima et al.

They then spent three days observing and getting images of the cows in their zebra disguises, noting any other fly-repelling things they might be doing like flicking their tails or twitching their skin.

They also painted the cows with black stripes for three days just to see if the paint might repel flies rather than the color of the stripes.

Unsplash | Conner Baker

Because who knows, the scent and fumes from paint could easily repel bugs. However, that was not the case.

Sure enough, the cows with stripes received far fewer bites.

PLoS ONE | Kojima et al.

Zebra-striping not only reduced the number of flies around the cows, but also reduced those fly-repelling behaviors by about 20%, too.

So the cows weren't bothered as much by the bugs they did attract.

And yes, the striping was the critical component.

Unsplash | Sunnie-Lee Davison

Holstein cows are black and white, just like zebras, but they're not striped, so they'll still feel the effects of bugs.

Not only does that confirm that zebra stripes prevent bug bites, but it also gives hope for a low-cost solution to the problem of bug bites.

PLoS ONE | Kojima et al.

It has to be much preferable to spraying chemicals around. However, the researchers cautioned that more work needs to be done, including looking at a larger sample size, different breeds of cows, and over longer periods of time, especially during peak season for biting insects.

Check out the full paper in PLoS ONE.