What Are Lizard Feet Called and How Do They Work?

Lizard feet go by a handful of technical names depending on context, but the most common anatomical terms are “pes” for the hind foot and “manus” for the front foot, with the underside called the “plantar” surface. Beyond terminology, how lizard feet actually work varies wildly across the roughly 7,000 species of lizards alive today. Some have sticky pads lined with microscopic hair-like structures, others have fused digits that work like tongs, and a few have fringed toes built for sprinting across water or burrowing into sand. The anatomy is more diverse and more engineered than most people realize.

Basic Anatomy and Naming Conventions

Lizards are pentadactyl, meaning they typically have five digits (toes) on each foot, though the number and proportions vary by species. The front feet are called the manus (plural: manus), and the hind feet are the pes (plural: pedes). Each digit consists of a series of small bones called phalanges, tipped with a claw in most species. The underside of each foot is covered in scales that differ in shape and texture depending on the lizard’s habitat and lifestyle.

Beneath the skin, tendons connect the muscles of the lower limb to the tips of each digit. In most lizards, the long flexor muscle of the digits ends in what researchers call a “flexor plate,” a tendinous sheet that often contains a small embedded bone called a sesamoid. Individual tendons branch off this plate and run to each fingertip. Some lizard groups break from this pattern: many anoles lack a complete flexor plate, with the flexor muscle instead running continuously into separate tendons for each digit. Most geckos have a reduced version of the plate with no sesamoid at all.¹ These structural differences reflect the huge range of gripping strategies lizards have evolved.

Gecko Toe Pads and the Setae System

The feet that get the most attention belong to geckos, and for good reason. The underside of a gecko’s toes is lined with millions of microscopic hair-like projections called setae. Each seta branches at the tip into hundreds of even smaller structures called spatulae, which are flat, paddle-shaped endings roughly 200 nanometers wide. These spatulae are what make physical contact with whatever surface the gecko is climbing.²

The adhesion does not rely on suction, glue, or any liquid. Gecko setae stick through van der Waals forces, the weak electromagnetic attraction that exists between any two surfaces when they are extremely close together. Researchers confirmed this by testing live Tokay geckos and isolated setae on surfaces with very different chemical properties. The setae stuck equally well to hydrophobic (water-repelling) and hydrophilic (water-attracting) surfaces, which ruled out mechanisms that depend on surface polarity or moisture. The geckos’ toes themselves turned out to be strongly hydrophobic.³ Van der Waals forces are individually tiny, but when millions of spatulae make contact simultaneously, the combined grip is strong enough to support the gecko’s body weight many times over.

The key engineering problem for geckos is not sticking but unsticking. If all those spatulae are pressed flat against a wall, how does the gecko lift its foot quickly enough to walk? The answer lies in geometry. When a gecko pulls its toes at a low angle relative to the surface, the spatulae lie flat and generate strong adhesion. When the gecko peels its toes away at a steep angle, the contact breaks almost instantly. Researchers have modeled this as a tape-peeling system, where the angle of detachment controls whether the foot grips or releases.⁴ That is why geckos curl their toes backward with each step, a motion called digital hyperextension.

Self-Cleaning Feet

You might expect that sticky feet would quickly become useless once they pick up dirt, dust, and debris. In practice, geckos keep their toe pads remarkably clean without any grooming behavior. The hyperextension motion that detaches the foot from a surface also serves as a cleaning mechanism. When setae snap free from the substrate, they generate enough inertial force to fling dirt particles off the spatulae. Geckos walking normally with hyperextension shed dirt about twice as fast as they would without it, recovering close to 80 percent of their original stickiness within just four steps.⁵

This is a passive process built into the gecko’s walking gait. There is no conscious effort to clean the feet. The physics of how setae release from a surface simply happen to also eject contaminants. It is an elegant example of a single motion doing double duty.

When Claws and Pads Work Together

People tend to think of gecko toe pads as the whole story, but claws play a surprisingly important role depending on the surface. Geckos that have both adhesive pads and claws use them in a context-dependent way. On smooth surfaces, the pads do most of the work because there is nothing for the claws to grip. On rough surfaces, the claws dig in and bear much of the load. On surfaces with intermediate texture, claws and pads function together, possibly in a way that is more than the sum of its parts.⁶

Experimental work on Australian geckos (family Diplodactylidae) quantified this trade-off. When researchers removed the claws, clinging ability dropped significantly on intermediate and fine-grained sandpaper surfaces but did not change on coarse-grained surfaces. The adhesive pads alone performed best on the coarsest textures, where the surface features were large enough for the spatulae to make good contact. As the surface became smoother and finer-grained, the claws became more essential for maintaining grip.⁷ In the wild, lizards encounter a huge range of surface textures on bark, rock, leaves, and human-made structures, so having two complementary attachment systems gives them flexibility.

How Gecko Feet Handle Water

Since gecko adhesion relies on van der Waals forces rather than chemical bonds, water on a surface can disrupt the close contact the spatulae need. But performance in wet conditions depends heavily on the surface chemistry of whatever the gecko is climbing. When tested on a hydrophilic (water-loving) surface, geckos produced roughly a third of the shear adhesion force they generated on the same surface when dry. But on a hydrophobic surface, wet and dry performance was statistically identical. In one striking result, geckos actually clung better to wet PTFE (Teflon) than to dry PTFE, generating about five times more shear force on the wet surface.⁸

The lipid coating on gecko setae may contribute to wet-surface performance. Gecko feet are coated with an ultra-thin layer of lipids that are naturally hydrophobic. One hypothesis is that these lipids help push water away from the spatulae, allowing closer physical contact with the surface even when moisture is present.⁹ However, experiments that stripped lipids from isolated toe-pad skin sheds found that substrate wettability mattered more than the lipids themselves for adhesion in wet conditions. When tested on hydrophobic surfaces, stripped setae still performed well in water, while all samples stuck poorly to hydrophilic surfaces regardless of whether the lipids were intact.¹⁰ So the surface the gecko is climbing matters at least as much as the chemistry of the foot itself.

Geckos can also recover their grip after being fully submerged. When allowed to step normally on a surface after being wetted, geckos regained full shear adhesion on glass in about 23 minutes, compared with nearly an hour if they were not allowed to step. On a less wettable surface, recovery was even faster, around 15 minutes with stepping.¹¹ The stepping motion appears to squeeze water out from under the spatulae in much the same way that hyperextension ejects dirt particles.

Chameleon Feet Work Completely Differently

Not every lizard foot is built for flat surfaces. Chameleons have some of the most unusual feet in the reptile world. Their toes are fused into two opposing groups, a configuration called zygodactyly. On the front feet, two toes are bundled together on the inside and three on the outside. On the hind feet, the arrangement reverses. The result looks and functions a bit like a pair of tongs, letting the chameleon clamp down on narrow branches with a powerful, stable grip.

The bones of the wrist and ankle in chameleons are heavily modified in both shape and number compared to other lizards. Despite this, most of the muscles found in typical lizard feet are still present and arranged in familiar positions. The big muscular differences involve broad V-shaped sheets of connective tissue (aponeuroses) that span the gap between the two fused digit groups, along with strong muscles that pull each group toward or away from the other. Researchers describe these fused digit clusters as “super-digits” because each bundle moves as a single unit rather than as individual toes.¹² Chameleons essentially traded digit independence for a vice-grip that locks them onto branches, which suits their slow, deliberate style of movement.

Running on Water With Fringed Toes

Basilisk lizards, sometimes called “Jesus Christ lizards,” are famous for sprinting across the surface of water. Their hind feet have elongated toes fringed with flaps of skin that expand when they slap the water, increasing the surface area of each stride. The mechanics of this involve two distinct phases in each step. When the foot strikes the water, the slap creates a pocket of air beneath the surface. The lizard then strokes its foot downward, pushing against the air cavity before it collapses. Most of the upward support comes from this downward stroke rather than from the initial slap itself.¹³

Juvenile basilisks, which are lighter relative to their foot size, generate the greatest support and propulsive forces during the first half of each step, when the foot drives vertically down into the water. They also produce large sideways forces that shift from inward to outward over the course of the step, helping with balance and forward propulsion.¹⁴ Larger, heavier adults lose this ability and end up swimming instead, because the forces their feet generate can no longer fully support their weight. The trick is size-dependent, not just species-dependent.

Toe fringes show up in other lizards too, though for different purposes. Desert-dwelling toad-headed agamas (genus Phrynocephalus) have fringed toes that help them move across and burrow into loose sand. Interestingly, the value of these fringes depends on the sand grain size. On fine, highly mobile sand substrates, lizards with their toe fringes experimentally removed actually buried themselves more effectively than those with intact fringes, suggesting that fringes can become a hindrance on the wrong type of sand. On coarser, more stable native sand, the fringes helped as expected.¹⁵ No single foot design is universally optimal. The best structure depends on what the lizard needs to do and where it lives.

Adhesive Toe Pads Evolved Repeatedly

One of the most remarkable things about sticky lizard feet is how many times they have appeared independently. Adhesive toe pads evolved at least 16 separate times across different lizard lineages. This makes them a textbook case of convergent evolution, where unrelated groups arrive at similar solutions to similar problems. Researchers compared toe pad development across 14 species spanning anoles and multiple gecko lineages, covering five independent evolutionary origins of the adhesive system. Despite the enormous evolutionary distance between anoles and geckos, both groups underwent strikingly similar developmental changes to build their toe pads.¹⁶

The setae themselves form through a process involving two specialized layers of skin that are part of the molting cycle. As a gecko sheds its skin, the shape of the new setae is determined by the interaction between these skin layers. This means the adhesive system is rebuilt from scratch with every molt, which happens every few weeks in many gecko species.² A gecko that damages its toe pads will have a fresh set within weeks. This built-in renewal system is part of what makes the adhesive system so robust over a gecko’s lifetime.

City Life Is Reshaping Lizard Toes

Evolution does not just explain the deep past of lizard feet. It is actively reshaping them in response to modern environments. Anolis cristatellus lizards living in urban areas of Puerto Rico have measurably different toes compared to their forest-dwelling counterparts. Urban lizards have larger toe pads, but the change is not simply a matter of scaling everything up proportionally. The pads cover a larger fraction of the total toe length, they are disproportionately longer relative to their width, and they have both more lamellae (the visible ridges on the underside of the toe) and wider spacing between individual lamellae.¹⁷

These changes make sense given the surfaces urban lizards encounter. Concrete, glass, painted metal, and smooth plastic are all common in cities and are quite different from tree bark and rock faces. Larger, more elongated pads with more lamellae would increase the total area of spatulae in contact with smooth artificial substrates, improving grip in environments where claws alone would be useless. The finding that these are disproportional shape changes rather than simple size increases suggests real selective pressure from the urban landscape acting on toe morphology.

Gecko-Inspired Adhesives in Technology

The mechanics of gecko feet have attracted intense interest from materials scientists and engineers. The appeal is obvious: an adhesive that is reusable, leaves no residue, works without liquid, and functions on a wide range of surfaces. Researchers have developed synthetic versions of gecko-inspired adhesives using microfabricated pillar arrays that mimic the structure of setae and spatulae.¹⁸ These materials aim to replicate the controllable adhesion that makes gecko feet so effective: strong grip in one direction, easy release in another.

Applications range from robotic grippers that can handle delicate objects without crushing them, to medical adhesives that stick to tissue without leaving chemical residue, to climbing robots designed for inspecting buildings or spacecraft. The challenge has been scaling up from the nano-level structures that work in a gecko’s foot to materials that can be manufactured reliably and perform consistently at larger scales. Progress has been steady but slow, partly because the performance of real gecko feet depends not just on the shape of the setae but on their material properties, their angle of deployment, and the dynamic peeling mechanics that living geckos control instinctively. Replicating all of that in a synthetic system turns out to be much harder than copying the geometry alone.