The study shows why geckos are the largest animals able to scale smooth vertical walls - even larger climbers would require unmanageably large sticky footpads.
In climbing animals from mites and spiders up to tree frogs and geckos, the percentage of body surface covered by adhesive footpads increases as body size increases, setting a limit to the size of animal that can use this strategy because larger animals would require impossibly big feet.
Humans would need about 40 per cent of total body surface, or roughly 80 per cent of front, to be covered in sticky footpads if we wanted to do a convincing Spiderman impression.
Once an animal is big enough to need a substantial fraction of its body surface to be covered in sticky footpads, the necessary morphological changes would make the evolution of this trait impractical, said Labonte.
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The researchers said that these insights into the size limits of sticky footpads could have profound implications for developing large-scale bio-inspired adhesives, which are currently only effective on very small areas.
"As animals increase in size, the amount of body surface area per volume decreases - an ant has a lot of surface area and very little volume, and a blue whale is mostly volume with not much surface area," said Labonte.
"This implies that there is a size limit to sticky footpads as an evolutionary solution to climbing - and that turns out to be about the size of a gecko," said Labonte.
Larger animals have evolved alternative strategies to help them climb, such as claws and toes to grip with, researchers said.
They compared the weight and footpad size of 225 climbing animal species including insects, frogs, spiders, lizards and even a mammal.