Spider-Man feats 'impossible' because of small feet Published duration 19 January 2016

image copyright Alamy image caption Marvel comic book superhero Spider-Man would have needed exceptionally big feet to scale tall buildings, say researchers

A human could not do what Spider-Man can unless 40% of the body was covered in sticky pads and they had impossibly large feet, according to new research.

Scientists in Cambridge, Australia and the USA comparing the weight and footpads of climbing creatures including spiders, found a size limit when it comes to the sticky pads.

A gecko is about the largest animal that can climb using this method.

They hope the study could help in the development of new adhesive substances.

In order to successfully scale a building the way Marvel comic book hero Spider-Man does, a human would need "impractically large sticky feet - our shoes would need to be a European size 145 or a US size 114", said Walter Federle, from Cambridge University's Department of Zoology.

Evolutionary limits

"We'd need about 40% of our total body surface, or roughly 80% of our front, to be covered in sticky footpads if we wanted to do a convincing Spider-Man impression," Dr David Labonte, from the same department, said.

image copyright Cambridge University/A Hackmann image caption Both geckos and spiders can do what Spider-Man cannot do

So, Spider-Man probably could not do what a spider can, but tree frogs, arachnids and geckos, can.

This is because of the percentage of their body surface covered by adhesive footpads, the researchers concluded.

The sticky pad percentage increases with body size setting an "evolutionary limit" to the size of animal able to use this climbing method.

Anything larger than a gecko would need "impossibly big feet", they said.

image copyright AP image caption A human would need to cover about 40% of their body with sticky pads and wear very large shoes to make it this far

The scientists compared the weight and footpad size of 225 climbing animal species.

'Good solution'

"We were looking at vastly different animals. A spider and a gecko are about as different as a human is to an ant, but if you look at their feet, they have remarkably similar footpads," Dr Labonte said.

"Adhesive pads of climbing animals are a prime example of convergent evolution, where multiple species have independently, through very different evolutionary histories, arrived at the same solution to a problem.

"When this happens, it's a clear sign that it must be a very good solution."

image caption Geckos are about the largest creature that can climb using the sticky footpad method of wall-scaling

Co-author Alex Dittrich, a PhD student at Anglia Ruskin University in Cambridge, said: "Different animals have come up with remarkably similar adaptations to dealing with the problem of climbing vertical surfaces, however it appears that there are size limitations on those using sticky footpads.

"Spider-Man might need to rethink his methods."