Lizards

[Terminator]

Has anyone seen them when they run up walls or go up glass, how do they do it, I've examined their feet and there are no miniture suckers on them or any sticky substance they secrete, their feet are quite smooth and dry, maybe its a mental capacity they have we don't know about.

 

[Houdini]

What about snakes? They don't even have legs and they can still climb up rocks and trees!

 

[Encurly]

Geckos have very fine hairs on their feet, which give them a large surface area which allow enough intermolecular attraction between their feet and the surface. There's a reasonable explanation here, although you might want to give some of the religious stuff towards the bottom a miss. (Or not, it's up to you).

I think snakes just use ordinary friction and strong underside muscles to climb - the surfaces are generally pretty rough, and you get more friction using your whole body than you do just with feet.