Why Do Zebras Have Stripes?
The bold black and white patterns that swathe a zebra’s coat is nothing short of amazing. While it was previously believed that zebras were white animals with black stripes and underbellies, it has since been concluded that zebras are black with white stripes.
This same iconic design has inspired many theories that speculate why zebras have stripes. Even renowned biologists Charles Darwin and Alfred Wallace famously debated about this issue back in the 1870s.
According to a team of researchers from a university in Hungary, there are as many as 18 theories for the possible functions of zebra stripes. Of these 18 theories, three are more prevalent than the rest.
Here are the three popular theories on why zebras have stripes.
1. To regulate body temperature
A 2015 research published in the journal Royal Society Open Science reported that the stripes may have evolved to keep zebras stay cool in the midday heat. Because of the zebras’ less efficient digestive ability, they have the need to forage for food at longer periods during the day. This makes it useful for them to have an additional cooling mechanism.
The researchers who are from the University of California Los Angeles conducted a comprehensive study that showed how temperature is a critical factor that is most strongly linked to striping. They found that the warmer it is, the more stripes on the zebra.
According to the research, the torso stripes help regulate body temperature and that heavily striped zebras have lower skin temperatures(3 degrees Celsius lower) than other non-striped mammals in the same area.
However, not all scientists agree with this theory. A 2018 study published in the journal Scientific Reports stated that findings did not support that the stripes have a cooling effect. The team used water-filled metal barrels to test the heat regulation hypothesis and found that zebra-striped barrels did not present a significant difference in temperature than plain covered barrels.
2. To repel insects
Another theory propose that the purpose of the zebra stripes is to repel disease-carrying flies. According to experiments, it has been shown that biting flies do not like landing on striped surfaces.
A biologist at the University of California Davis, Tim Caro, supports this theory. He said that similar studies that his team conducted have shown that striping is linked to repelling biting flies. Caro added that these flies, like horseflies, can carry really nasty diseases such as equine influenza.
This reason may seem strange especially for humans who see zebras as stand-out animals. But according to some naturalists, the stripes of zebras can potentially serve to confuse predators. The wavy lines of the stripes enable them to easily blend into their natural habitat like big blades of grass. This is because their main predators, lions, are known to be colour blind. This means that a striped coat with alternating colours may be more confusing than just a single block of colour.