Question: Do you have any theories on how a gecko sticks to walls?

Jess Smith answered on 11 Mar 2014:

What a good question- I was at a materials science conference a few weeks ago and there was a talk on this topic! We often look towards nature to get answers to modern materials problems.

The secret is in the materials science in their feet. If you look at a geckos foot in an electron microscope (a special kind of microscope that allows you to see much smaller features than an optical microscope) then you can see that the surface is split up into hair like structures, which balloon out at the ends. This allows the gecko’s foot to make very good contact with the surface. In turn this means that the Van der Waals forces between the geckos foot and the wall are enough to keep it stuck on. Van der Waals forces are a normally quite weak attraction (if you aren’t sure what they are feel free to ask me or your teacher for more information!). If there wasn’t a good connection then the Van der Waals forces would not be enough. Imagine putting a flat sheet on top of a bumpy surface- there would be lots of places where the sheet and the surface weren’t able to touch. This is what it would be like with our hands (the flat sheet) on top of a wall (the bumpy surface- these bumps are incredibly tiny!).

It is a very neat solution, because it means that the gecko doesn’t waste energy producing secretions that may have allowed it to stick to the wall (like snails), and it can move very quickly as the sticking/ removing is instant.

I hope this helps!