The characteristic stripes on the zebra's body do not provide the animal an advantage against predators contrary to what was initially thought, according to new research conducted by the University of Cambridge.
Researcher Anna Hughes from Cambridge's Physiology, Development and Neuroscience Department led a team of scientists in studying the effectiveness of the zebra's stripes in concealing it from its would-be hunters.
In a study featured in the journal Frontiers in Zoology, the researchers asked 60 participants to play a video game in which the main goal is identify specific targets in different settings. They discovered that striped targets were more easily spotted and captured in the game compared to those with uniform gray markings when different targets were present.
This finding contradicts earlier suggestions that stripes, such as the ones on zebras, developed throughout the animal's evolution to make it more difficult for predators to attack them when they move in groups.
"We found that when targets are presented individually, horizontally striped targets are more easily captured than targets with vertical or diagonal stripes," Hughes said.
"Surprisingly, we also found no benefit of stripes when several targets were presented at once, despite the prediction that stripes should be particularly effective in a group scenario."
Hughes added that this could be caused by the various stripe orientations and how they interact with the perception of motion, where failure to read the correct speed of a target allows the predator to capture its intended prey.
Patterns such as zigzags, stripes and highly contrasting markings help make target animals highly visible, especially to predators. Scientists have long studied whether the movement of the animal is vital in understanding why such patters have evolved throughout the years. It is generally believed that striking patterns could confuse potential predators and lessen the animal's susceptibility to capture or attack.
The term 'motion dazzle' was coined to refer to ability of high contrasting patterns to deceive predators regarding the direction and speed of a moving prey. It has been proposed that motion dazzle is most effective when applied in groups of animals, such as when zebras move in herds.
Hughes said that the motion of the target may only be one aspect of the bigger picture, with various stripe orientations evolving for different functions. She said that the development of different types of patterns is complex, with no single factor over-ruling its evolution.
She also pointed out that further studies must be made in order to fully explore the true value and significance of motion dazzle to the ecology.
