For Spider-Man to actually scale a building, he’d need way bigger hands. New research on how the size of animals’ adhesive pads impacts their climbing abilities finds that he’d need impossibly large sticky hands and feet—a size 114 in men’s shoes, in fact.
Led by Cambridge zoologists, an international group of researchers examined 225 climbing animal species, from mites and spiders to geckos. Their study, published in the journal PNAS, finds that the surface area of animals’ adhesive pads increases proportional to their body weight.
Insects like ants and mites have a lot of surface area on their bodies, but comparatively little volume. Heavier animals need greater adhesive power to scale a wall, but there’s not as much available area to put the amount of sticky pads that would be required to lift their weight. Geckos are the largest animals that can successfully scale smooth, vertical walls, and they use 200 times more of their body’s total surface area for adhesive pads than a mite. If we extrapolate that to humans, it’s clear that Spider-Man would need a whole lot of sticky pads.
"If a human, for example, wanted to walk up a wall the way a gecko does, we'd need impractically large sticky feet—our shoes would need to be a European size 145 or a US size 114," according to Cambridge zoologist Walter Federle, the paper’s senior author. Spider-Man would need 80 percent of the front of his body to be adhesive to climb a smooth wall. Essentially, he’d be doing the worm up a building instead of crawling on his hands and feet.