Geckos do not have sticky feet

A crested gecko walking up the side of a glass tank is not sticking to it in any normal sense. There is nothing tacky on its feet and no suction involved.

The underside of each toe is covered in rows of microscopic hairs called setae, and every one of those splits again into hundreds of even smaller tips. The result is a surface that makes contact with glass at a scale so fine that a weak molecular attraction called the van der Waals force becomes strong enough to hold the whole animal up.

It only works because the contact is so complete. It also switches off instantly. A gecko lifts a toe by peeling it from one edge, which breaks the contact and releases the grip in a fraction of a second.

Not every gecko has this. Leopard geckos and African fat-tailed geckos have claws instead of adhesive pads, which is why they live on the ground and their enclosures are set up wide rather than tall.