The Science Behind Geckos Sticky Feet

Do geckos have sticky feet? It certainly looks like they do when you see them crawl around on the wall or ceiling.

These lizards are amazing and can move across sheer vertical surfaces that other animals would otherwise fall off of simply because of the science of their feet, which could be sticky, but are they? Let’s take a look at what these wall-crawling lizards are capable of when it’s time to scuttle away and move up the wall, across the ceiling, or back down the wall as they go after the insects that might be their next meal.

The Microscope Tells the Story

When viewed under a microscope, the feet of a gecko have been found to have microscopic hairs that are attached to each toe to cling to flat surfaces. That’s not all that we find with these feet. Each of those little hairs, which are called setae, also has hundreds of finer spatula-shaped ends that make contact with a surface to allow the lizard to move around on a flat surface, whether it’s horizontal or vertical. These creatures can even walk around on the ceiling and make it from one end of the room to the other.Even though we think of surfaces as flat, they really aren’t

Even a surface that appears to be flat has microscopic bumps and troughs, which are what the tiny ends attach to so the gecko can move across the surfaces. The sticky feet of geckos aren’t really sticky at all; they use the same force that bonds molecules together to ensure the animal can crawl along even if the surface seems unlikely for the movement from one place to another. Even though these forces are weak, with millions of tiny hairs, there’s more than enough force to attach this critter to just about any surface.

Some Geckos Just Don’t Stick

Most of the geckos we are used to seeing have sticky feet, but there are some that just don’t stick to anything. If you were to grab one and try to attach it to a wall or ceiling, the poor creature would fall down and might not survive. There are nearly 1,450 species of geckos, and nearly 40 percent of those have non-stick feet. There are even some of these animals that have legs at all, which seems like they can’t do much at all.

Innovations Made Are Sometimes Lost

The phenomenon of gaining evolution and then losing it is called convergent evolution. This happens when different groups of the same animals independently develop the same traits as a solution to the challenges they face. In this case, some gecko species were faced with sheer surfaces and a need to climb them and move about. Different varieties of these animals have evolved feet with the little hairs on them to make sure they can move across the surfaces that are smooth and vertical or even upside down when they move across the ceiling of a building. If the need for the adaptations developed disappear, the adaptations also leave the species.

Where Did the Gecko Come From?

The earliest days of the dinosaurs found the gecko amongst the animals that emerged. These little critters found their way to the world between 180 and 225 million years ago. We know that when the dinosaur time on the planet was coming to an end, geckos had already evolved their sticky feet, which was quite a feat at that time. We know this because there was a preserved fossil entombed in amber that showed these feet with the little hairs on them.

Over the time this animal has been on the planet, they have developed their adhesive-style toes in at least eleven separate events. Strangely, and once again proof of convergent evolution, nine times these animals lost this adaptation. We aren’t certain this is the exact number of times this has occurred, but it does show us a picture of what these animals are capable of and the fact that they don’t keep their feet with the little hairs on them when they don’t need them. Can you imagine if we were capable of convergent evolution and would lose something when we didn’t need it any longer?

Do Geckos Leave Any Sticky Residue?

By now, you likely know the answer to this question. When a gecko moves across a sheer surface, they don’t leave any sticky residue because their feet aren’t actually sticky. Don’t expect to find the same sludge you might find when a snail moves about, which leaves a trail of mucus that seems a bit gross. You won’t see any trail or proof that a gecko moved around on the wall or ceiling at all.

The Setae Aren’t Sticking Out Straight

The tiny setae on the bottom of the feet of a gecko don’t stand up straight or at a 90-degree angle. These little splits are situated in different directions to make it much easier for them to move about along the sheer surfaces. Some scientists have done the math on the subject because the closer to horizontal that these little hairs bend, the increased stickiness that these little hairs can offer to support more weight of the animal. These impressive little items on the bottom of the feet are quite extraordinary.

Setae are also extremely flexible, allowing the gecko to jump to another surface or quickly change direction to escape a predator. The toe hairs must absorb the energy it would take to redirect the animal in the desired direction. These little animals can move around at any angle on just about any surface, thanks to the setae on the bottom of their feet.

Amazing Little Lizards

You don’t have to keep your vision of geckos limited to Geico commercials; they have sticky feet that are interesting and not made of anything that’s actually sticky at all. Now that you know a little more about these creatures, you might want to study them more, have one as a pet, or just watch a couple of nature shows featuring geckos.