If you had been hoping that one day a bite from a radioactive spider would grant you the ability to scurry up the side of buildings with ease, you also better wish that bite increases the size of your hands and feet— a lot —as the Cambridge study “Extreme positive allometry of animal adhesive pads and the size limits of adhesion-based climbing” explains.
While some arachnids, insects, and lizards can walk on walls, seemingly defying gravity—and it’s done via adhesive pads on their limbs.
A gecko, for example, has billions of tiny hair-like structures sprouting out of such pads—hairs small enough to make use of the connecting nature of Van der Waals forces — electric charges that create attractive energy.
All those other aforementioned creatures also take advantage of what Van der Waals forces can do — but their footpads are relative to body surface area — so a smaller animal, like a mite, doesn’t need as large a pad as does the gecko.
The study points out that body surface area per volume decreases as an animal’s size increases — meaning the minuscule mite only needs a sticky pad equal to about .02 percent of its body surface area, while a gecko needs more than four percent worth of foot padding.
By this standard, a human being would need about 40 percent in pads to make the trip up a wall — and as a person doing so would likely be facing the surface being climbed, 80 percent of the adhesive padding would need to be on the front of the body.
“If a human, for example, wanted to climb up a wall the way a gecko does, we’d need impractically large sticky feet,” says Walter Federle, the study’s senior author and member of Cambridge’s Department of Zoology to the The Telegraph, adding would need 43-inch hands “and shoes in European size 145 or US size 114.”
Then again, this guy seems to be on the right track: