Why Do Cows Have Spots?

Have you ever wondered why cows have spots? Well, genetics obviously – just like some of us have darker or lighter skin or hair. But it turns out there MIGHT just be another good reason why cows tend to be speckled – fly repellant!

We already know that cows like to use their long tails to swat away flies, but Zen Faulkes, an evolutionary biologist at the University of Texas Rio Grande Valley, says that cow spots may also help keep the bugs at bay, horseflies in particular.

It’s just one study, but according to Faulkes, the dark and light spots on a cow’s coat confuse horseflies’ vision, which is tuned to see polarized light. The spots somehow change how that light is reflected, and deter the flies from landing on the cow. The more spots a cow has, the less likely it is to be targeted by flies!

Pretty cool theory – buuuuuut, based on our experience in the barn yard, pretty much all of the cows (speckled or not) are busy swatting flies all day.

So I guess we’ll never know for sure. Couldn’t hurt to try some polka dot clothing for the Spring, though!


Leave a Reply

  • (will not be published)