The function of stripes on zebras has sparked an interesting debate among zoologists for decades. One of the most widespread hypotheses considers that these serve to blend in with the environment . However, a recent study carried out by a team of researchers from the universities of California, Davis (USA), and Calgary, Canada, seems to refute this idea.
After estimating the distance at which lions and hyenas perceive stingrays, these experts have been able to determine that they are not very effective as camouflage, because before predators can detect them, it is very likely that they have already heard or sniffed. its owners.
In general, it was thought that in wooded areas, black stripes allowed zebras to blend in with tree trunks and white stripes with beams of light that filtered through their canopies. In an essay published in the journal PLOS ONE , these scientists, coordinated by the professor of biological anthropology Amanda Melin, from the aforementioned Canadian institution, indicate that, in reality, predators can barely perceive them at more than 50 meters when it is daytime , already over 30 when evening falls. On new moon nights, they cannot be distinguished more than 30 feet.
To determine this, they used filters that allowed them to simulate how carnivores would see them through their own eyes . In his opinion, this suggests that stripes are not a concealment tool. What’s more, in the open spaces, where zebras spend most of their time, lions and hyenas are able to perceive their silhouette as easily as that of other possible prey of similar size.
Timothy Caro, a biologist at the University of California who has also participated in this initiative, suggested long ago that stingrays could be an evolutionary adaptation that would allow these quadrupeds to avoid the bites of some insects .
Update (02/21/2019) : Finally, in 2019 Tim Caro managed to prove his hypothesis: zebras have stripes to deter blood-sucking flying insects.
Image: Rui Ornelas via Wikimedia / CC
