(ORDO NEWS) — Biologists from Finland found that the zigzag pattern on the back of ordinary European vipers not only hides them from the eyes of others, but also creates optical illusions that prevent predators from catching the snake, even if they could notice it. Scientists published the results of the work in the scientific journal Animal Behavior.
“We checked whether zigzag patterns on the back of vipers can protect them from predator attacks, both by hiding them from attention and by generating optical illusions associated with the merging of fast-moving stripes. It turned out that both of these effects work equally well, which suggests that the protective coloration of animals can be multifunctional, “the researchers write.
Vipers, rattlesnakes and their relatives from the Viperidae family hunt small mammals and reptiles from an ambush, jumping at a tremendous speed and literally “driving” their fangs into the body of the victim. One of the secrets of their success has long been considered a zigzag camouflage coloring of their scales. It helps reptiles to merge with the forest litter and hide itself from the attention of the victim until the moment when she comes close enough. Scientists suggest that these same bright patterns serve as a warning to predators who are trying to attack the snake.
Finnish biologists, led by professor at the University of Jyväskylä (Finland), Joanna Mapps, have discovered other properties of protective vipers. They watched as several volunteers tried to see dummy snakes, as well as real vipers in the forests around their city, as well as in several research stations.
During the experiments, scientists checked how differences in the color of snakes, their size, speed and body position influenced the likelihood that a person or any other potential predator will see it.
The experiments showed that the appearance of zigzag stripes of any color and size significantly reduced the likelihood that the viper of any size and type of color can be detected. In turn, monitoring the speed of creeping snakes showed that they are moving fast enough to produce an effect that neurophysiologists call the “flicker fusion”.
So scientists call a special psychophysical effect, due to which people do not perceive the flicker of any light source or object, if they occur with a sufficiently high frequency. A striking example of this is the usual incandescent lamps that produce flashes of light with a frequency of 100-120 hertz. In most cases, a person does not notice them.
This effect also works on vipers: if the snake moves fast enough, all the strips on its body merge into a single whole. This, on the one hand, confuses the observer, and on the other hand, it prevents the eyes of a person or a predator from determining the direction of movement and the distance to the creeping reptile. Stripes on the body of zebras play a similar role, which prevent flies from landing on the body of these animals and make lions believe that their prey runs faster or slower than it actually is.
In the past, according to Mapps and her colleagues, many scientists believed that the masking color of animals performs one specific task – it hides them from the attention of enemies or scare and confuse predators. The example of zigzags on the back of vipers, as the researchers conclude, suggests that these ideas are far from always true.
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