Wildlife resembling natural objects like stones, sticks or leaves avoid predators nearly four times as long as undisguised animals
Animals that resemble inanimate objects are better able to evade predators than those that use other kinds of camouflage. Predators took four times as long to find animals using this type of visual trickery, called masquerade camouflage, than they did for undisguised animals.
Evolution has equipped animals with a wide range of ways to conceal themselves from predators: zebras’ stripes make them difficult to isolate from a herd, some spiders are overlooked because they resemble bird droppings and colour-shifting chameleons are able to fade into the background. But, until now, no one had examined how these hide-in-plain-sight approaches stack up against each other.
“A comparison between the types of camouflage had never been done,” says João Vitor de Alcantara Viana at the State University of Campinas in Brazil. “We thought it would be a great opportunity to understand how camouflage evolved and how the types of camouflage interact.”
To find out which camouflage strategy was most effective, Viana and his colleagues compiled data from 84 publications on a variety of predators and prey. Most studies included insects being hunted by birds, fish or humans – either in real life or, with humans, in a computer-game style simulation.
They found that having any form of camouflage increased predator search time by an average of 63 per cent and decreased the likelihood of an attack by 27 per cent. But animals that employed what’s known as masquerade camouflage – resembling a rock, plant or poop, for instance – were the most successful in delaying an attack, increasing predator search time by 295 per cent.
Other camouflage methods, like blending into a backdrop or having chaotic colour patterns, increased predator search time by roughly 55 per cent.
“Each individual study is like a little jigsaw piece, and they’re trying to actually put part of that jigsaw together,” says Anna Hughes at the University of Essex in the UK. She says the paper is also “really useful for seeing where the gaps in our knowledge might be”.
One such gap is geographic, says study co-author Rafael Campos Duarte at Federal University of ABC in Brazil, because most of the studies on camouflaged species that the researchers were able to review are from North America and Europe. As the body of research grows, they hope to examine the phenomena on an even more diverse, global scale.
Journal reference: Proceedings of the Royal Society B: Biological Sciences, DOI: DOI: 10.1098/rspb.2022.0980
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