Here’s What Happens When Zebra Stripes are Added to Horses

The zebra’s striking stripes have fascinated people for centuries. Books, poems, paintings, clothing, and more have been dedicated to its illustrious pattern. There are many theories on why zebras have stripes, and scientists are digging deeper to find the truth. Not only did they find zebra stripes have an incredibly useful purpose, but also have something to lend to its other equine family members. Find out what happens when zebra stripes are added to horses!

Zebras Standing on Grass During DaytimeDavid Tomaseti on Unsplash

Zebras Stripes Aren’t Meant to Hide

It’s a very popular opinion that zebras have stripes in order to camouflage themselves from predators. However, lions and hyenas make a meal out of zebras more often than any other animal in the wild, so that can’t be true. Some think the zebra with the best stripes gets the best mate, but scientists have noted no difference in grooming habits with zebras who have the most stunning stripes and those who don’t. It was also once believed stripes helped regulate zebras body temperatures, but studies have shown there is no difference in heat load between zebra stripes and uniformed pelages. So, why do zebras have stripes?

The Flies Have It When It Comes to Zebras

As it turns out, zebra stripes repel tabanid bites. Tabanids, commonly known as Horse-flies, are a large and diverse group of blood sucking flies that like to feed on animals like zebras. They carry diseases that are deadly for zebras like, trypanosomiasis, equine infectious anemia, and African Horse Sickness. Zebras are especially susceptible to disease because of their thin pelage, which allows flies to easily bite and feed on them.

Zebra Stripes: Where Fashion Meets Function

The good news for zebras is that their stripes are excellent weapons against deadly fly bites. Studies have shown zebra stripes confuse flies and majorly disrupt their landing patterns. Flies have a hard time distinguishing zebra stripes from a distance. When they get closer to a zebra, its stripes become visible, occupy most of the fly's visual field, and disrupt its optic flow. Optic flow is defined as the apparent motion of an object caused by movement between an observer and a scene. Think of the barber pole illusion or the sense of buildings and trees moving backward when you’re sitting on a train, for example. This disruption makes flying and landing especially difficult.

Scientists believe a zebra’s stripes disrupt a fly’s vision so much that it prevents it from switching into an optic mode, which aids in helping it land on its intended target. Upon approaching zebra stripes, flies have been seen flying at much faster rates towards their targets. This causes them to collide with zebras, erratically turn away, or abort the landing all together. When a fly actually lands on a zebra, it swiftly takes off.

Housefly on Board, Jin Yeong Kim on Unsplash

There’s Science Behind the Stripe 

In a study led by Professor Tim Caro, three captive plains zebras and nine horses were observed in separate, but adjacent fields. The horses were uniformly colored white, grey, brown, and black. For about 16 hours, scientists watched every fly approach each animal. The results are incredible! They found flies landed on the zebras considerably less than the horses, spent much less time investigating the zebras, and flew away faster from zebras. In fact, the zebras were bitten by flies less than horses overall.

However, zebras also displayed more actions like tail swishing and running away from flies than horses. 

It’s Time for a Costume Party

It’s well known that horses have problems with flies too, and are also susceptible to infection from their bites. So, a few amazing scientists went to work in order to find out if zebra stripes worked for horses too. As it turns out, zebra stripes on a horse could be just the key to keep pesky bites at bay

In another study, scientists pinned custom printed striped, black, and grey fabric on commercial horse rugs. They found that fly landings differed significantly according to what fabric a horse was wearing. Most flies landed on black and grey rugs, and avoided the horses wearing stripes. This study also found flies approached the striped horses faster than the horses wearing black or grey.

Horses Should Look Like Zebras

The results are pretty clear. If a horse wears stripes every day, it keeps the flies away. Luckily, it hasn’t taken long for the news about zebra stripes to reach horse lovers everywhere, and you won’t need to order a custom print. It’s recommended that you purchase a zebra patterned horse rug that comes up high around the neck, because scientists have found that stripes on a horse's body did not deter flies from biting its face and neck. Zebra patterned horse rugs are available commercially in a few different styles, fabrics, and prices.