Geckos

Geckos live in a wide range of habitats including tropical rainforest, parched deserts, and icy mountain peaks. In the Philippines some geckos prefer living inside the houses than staying in their natural habitat. At night the lights attracts so many insects that all gecko needs to do is cling to the ceiling and wait for prey to fly by. Now, how are these lizards (geckos) attached to the ceiling and walls without falling?

Geckos stick remarkably well to surfaces that should be really hard to stick to. According to my research, there are no footings or opportunity for Velcro-style attachment on clean glass, but they have no worry with that – indeed, perversely, they have more trouble sticking to dirty glass than clean glass. Their toes are not suction cups, nor are they sticky in the sense of stickers or adhesives. Their toes are waterless or dry and leave no sticky residue behind where they walk. Even stranger, geckos are able to control their stickiness: a gecko walking along your arm lifts his feet with no trouble, but if you try to pick the gecko up, his toes suddenly adhere to your skin.

As what I have said, Geckos feet are not naturaly sticky. And according to the book entitled "Wildlife” , In 2000,  biologists documented, for the first time, that geckos take advantage of van der Waal forces, a form of weak attraction between atoms and molecules. This attraction between particles is formed from interactions between negatively-charged electrons, existing in clouds around protons, having a positive charge. This can create temporary attractions between the atomic bodies. And that is why geckos can hang out on walls and ceilings.