The exploits of Spider-Man have been well documented in the pages of comic books as well as on the silver screen, but could there ever actually be a such a super hero? Obviously, the answer is no, but the reason why his existence is impossible might not be what you’d expect.
Even in the implausible instance that somebody like Peter Parker actually did gain superhuman strength and agility from the bite of a radioactive spider, he still would not be able to pull off the feats credited to the fictional Spider-Man, according to a new study from Dr. David Labonte and his colleagues in the University of Cambridge’s Department of Zoology.
As Dr. Labonte’s team explained in a paper published this week in the journal PNAS, in order to scale up a wall like Spider-Man, a person would need to have adhesive pads covering roughly 40 percent of their body surface, or approximately 80 percent of the front of their bodies.
Even then, such a feat would be impossible without significant anatomical changes, senior author Walter Federle, also from Cambridge, explained in a statement. “If a human… 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,” he said.
Geckos are the largest possible wall climbers, study claims
The study authors examined 225 different species of climbing animals of different sizes, and found the area of the adhesive pads required to climb walls scaled along with their weight. In other words, geckos needed adhesive pads on 200 times more body area than mites, and larger creatures would have to have “impossibly big feet” in order to scale walls.
Thus, Dr. Labonte’s team concluded that there is a limit to the size of animal capable of using this strategy, and that the geckos are the largest possible adhesion-based climbers. In addition to crushing the dreams of comic book enthusiasts everywhere, their findings could have a profound effect on the development of biologically-inspired, wall-climbing adhesive technology.
“As animals increase in size, the amount of body surface area per volume decreases,” explained Dr. Labonte. “An ant has a lot of surface area and very little volume, and a blue whale is mostly volume with not much surface area. This poses a problem for larger climbing species.”
When such creatures are larger and heavier, “they need more sticking power to be able to adhere to vertical or inverted surfaces, but they have comparatively less body surface available to cover with sticky footpads,” he pointed out. “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.”
One possible solution to the problems involving the development of artificial adhesives would be to find a way to enhance their ability to fasten to the wall – in other words, to make them stickier. Dr. Labonte acknowledged such a possibility, saying “there is a lot of interesting work still to be done” and that such advances “would likely have very useful applications in the development of large-scale, powerful yet controllable adhesives.”
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