A common sight in homes, Geckos are amazing creatures that are often overlooked by people when spotted.
Geckos can stick to walls using tiny hair-like structures on their toes, called Setae. They climb walls to get away from harm and also to hunt their prey.
How Geckos Stick to Walls
Geckos have a remarkable ability to stick to surfaces vertically or even upside down!
Their ability comes from hundreds of thousands of microscopic hair like structures called Setae. At the end of each Seta, there are about 1000 extensions called Spatulae, which are extended outwards.
These Spatulae are so tiny that they actually bond with the surfaces they touch at a molecular level. This causes dry adhesion, which means that they can stick to surfaces without using liquids or surface tension.
Just one Seta is strong enough to lift the weight of an ant. Since there are literally millions of them on a gecko, theoretically, a Gecko could support 280 pounds of weight if it used all of its Setae at the same time!
Scientists used to assume that this ability to stick was related to the size of the toes. However, it was later discovered that the Geckos’ bodies become stiffer as they grow bigger. So the bodies act like a spring, giving their toes even more power to support the weight they have gained due to growing up.
The tendons, skin, connective tissue and Setae all become stiffer as they grow older.
Geckos can balance out the force of gravity by applying their own force to a wall. They can press and slide their feet toward their bodies and drag their feet across vertical surfaces without losing their grip.
Limitations of Geckos’ Sticking Ability
When a Gecko sheds its skin, the sticking ability gets inhibited temporarily, when the older skin has loosened up but still hasn’t been shed yet.
Geckos can’t stick to surfaces that are wet or have a lot of dust on them. The Setae will cling to the water / dust, but not to the wall. Similarly, very soft and oily surfaces can’t be stuck to either.
Geckos also cannot stick to surfaces that are coated with non-stick coatings.
Why Geckos Climb Walls
Geckos climb walls to get away from perceived threats like humans and their pets, like cats and dogs.
They also tend to wait near light sources high up on walls. Since insects are attracted to light and fly around bulbs and tube lights, they are ideal hunting spots for Geckos.