If you’ve ever seen a gecko crawling around your home or garden, you may have wondered – are geckos amphibians? With their small size, sticky toes, and big eyes, it’s an understandable question. While geckos do share some similarities with frogs, toads, and salamanders, they are actually reptiles, not amphibians.
In this comprehensive article, we’ll cover the key differences between reptiles and amphibians, delve into the unique features and behaviors of geckos, and clearly explain why geckos are classified as reptiles, not amphibians.
If you’re short on time, here’s a quick answer to your question: Geckos are reptiles, not amphibians. While amphibians like frogs and salamanders live part of their lives in water and have permeable skin, geckos are fully terrestrial reptiles with scales and claws.
They lay eggs on land and are incapable of breathing underwater through gills like amphibians.
Differences Between Reptiles and Amphibians
Amphibians Spend Part of Their Lives in Water
Unlike reptiles which lead completely terrestrial lives, most amphibians spend their early developmental stages in water and remain dependent on water sources as adults. For instance, frogs and salamanders hatch as tadpoles in ponds or lakes, breathing through gills, before metamorphosing into air-breathing adults.
Their permeable skin and reproduction systems still require moisture, so they remain tied to damp environments.
Amphibians Breathe Through Gills as Larvae
Amphibian larvae (tadpoles) breathe via gills and do not yet have lungs. This allows them to extract oxygen while living underwater. As they develop into adults, amphibians form lungs and breathe air. But some salamanders retain gills for life, which gives them flexibility to breathe both underwater and on land.
Amphibians Have Moist, Permeable Skin
A key feature of amphibians is their smooth, glandular skin which lacks scales or claws. Being permeable, their skin easily absorbs water and oxygen but also makes them prone to dehydration. This dependence on moisture restricts them to humid habitats.
Reptiles Are Fully Terrestrial
In contrast to amphibians, reptiles lead entirely land-based lives, having adapted to survive on dry land. They hatch from eggs as fully developed miniature adults and undergo no major metamorphosis. Being amniotes, reptile eggs contain protective membranes and are laid on land rather than in water.
Reptiles Breathe Through Lungs
Reptiles have well-developed lungs suited to breathing air. Even aquatic turtles surface frequently to gulp air. Having no gills, reptiles cannot obtain oxygen underwater for extended durations. Their efficient lungs and cellular respiration systems adapted them for permanent life on land.
Reptiles Have Scales and Claws
The reptilian skin consists of tough, dry scales or scutes which prevent water loss, unlike the permeable amphibian skin. Scales interlock to form armor that shields the body. Keratin deposits often harden them into bony plates on crocodilians and turtles.
Claws, horns, or scutes provide additional protection. This allows reptiles to thrive in arid environments.
Key Features and Behaviors of Geckos
Geckos are Terrestrial
Unlike frogs or salamanders, geckos are terrestrial creatures that live primarily on land. They have adaptations like sticky toe pads that help them climb vertical surfaces and hide in trees or rocks. While some geckos are skilled climbers, they don’t have webbed feet or live in water like amphibians do.
Geckos Breathe through Lungs
Geckos are reptiles that breathe through lungs, not gills. They don’t go through a larval stage with gills like frogs and salamanders. Geckos take in oxygen and release carbon dioxide through breathing. Their lungs allow them to live on land without needing an aquatic environment.
Geckos Have Dry, Scaly Skin
The skin of geckos is dry and covered in scales, unlike the moist smooth skin of amphibians. The scales and dry skin help prevent water loss, an adaptation for terrestrial life. Amphibians have permeable skin that needs to stay moist for cutaneous respiration.
But the scaly skin of geckos contains very little water and allows them to thrive on land.
Geckos Lay Eggs on Land
Female geckos lay eggs with soft, flexible shells on land in secure locations like rock crevices or tree holes. The eggs are incubated in the environment, not in water. This is another key feature that separates geckos from amphibians that reproduce in water and lay eggs without shells.
The reptilian eggs of geckos have protective shells and membranes adapted for terrestrial egg-laying and incubation.
Geckos Have Sticky Toes and Prehensile Tails
Geckos are equipped with specialized toe pads covered in microscopic hairs that utilize van der Waal’s forces to stick to surfaces. This allows them to climb vertical surfaces with ease. Their tails are also prehensile, acting as a fifth appendage that helps balance and grip.
These unique adaptations maximize mobility in their arboreal habitats. In contrast, amphibians have not evolved sticky toe pads or prehensile tails since they primarily live in aquatic environments.
Gecko Classification as Reptiles
Geckos Share All Reptile Characteristics
Geckos possess all of the key characteristics that define a reptile. Like all reptiles, geckos are cold-blooded animals that rely on external heat sources to regulate their body temperature. Geckos have scaly skin made up of horny plates known as scutes, a trait shared by all squamates (lizards and snakes).
Additionally, geckos lay soft-shelled leathery eggs, a key reproductive trait of reptiles.
Geckos share numerous physical features with other reptiles as well. They have claws on their feet for climbing, slender tails that can drop off to escape predators, and exceptional hearing and vision. Their skulls and skeletons share similarities with other lizards in particular.
Thus, by any morphological or physiological definition, geckos qualify as reptiles.
Geckos Lack Amphibian Characteristics
In contrast to reptiles, amphibians like frogs have moist smooth skin without scales or claws. They lay shell-less eggs in water or damp environments. Geckos lack these amphibian qualities, instead having water-resistant skin and hard-shelled eggs adapted to drier habitats.
While some amphibians can live outside of water for extended times post-metamorphosis, they remain much more dependent on water to prevent desiccation. Geckos are fully terrestrial lizards with adaptations for life independent of water in arid environments.
Gecko Evolutionary History Aligns with Reptiles
Molecular evidence shows that geckos share a common ancestor with all squamates (lizards and snakes), branching off from that lineage sometime during the late Jurassic over 150 million years ago. Geckos belong to the infraorder Gekkota, which diverged evolutionarily from other lizards relatively early but are nonetheless nested phylogenetically within squamates.
In contrast, the evolutionary lineage that led to modern amphibians is thought to have diverged from reptiles over 300 million years ago during the Carboniferous period. Thus geckos align with and fall squarely within reptiles based on their evolutionary history.
Common Misconceptions About Gecko Classification
Misconception: Geckos Live in Water
Many people mistakenly believe that geckos are amphibians that live in water, like frogs or salamanders. However, geckos are actually reptiles that dwell exclusively on land. While some gecko species live in humid, tropical areas, they do not spend time living underwater.
Geckos have specialized toe pads that allow them to climb vertical surfaces, so they tend to live in trees, rocks, caves, and man-made structures rather than bodies of water.
Misconception: Geckos Have Smooth, Wet Skin
Another common misconception is that geckos have moist, smooth skin like frogs. In reality, geckos have dry, rough, scaly skin that is designed to retain moisture in arid environments. Their skin consists of many small scales that fit together like puzzle pieces and feel rough to the touch.
Geckos also lack the slick mucus coating that helps amphibians breathe through their skin. While gecko skin may appear shiny, it is not actually wet or slippery.
Misconception: Geckos Undergo Metamorphosis Like Frogs
Some people think geckos, like frogs, hatch from eggs as tadpoles and transform into their adult form through metamorphosis. However, geckos are amniotes, meaning they develop within an egg that contains protective membranes and fluid.
Gecko eggs are laid on land, and baby geckos emerge looking much like tiny adults. While the babies shed their skin frequently as they grow, geckos do not undergo the dramatic morphological changes of amphibian metamorphosis. Their body shape stays fundamentally the same from birth to maturity.
Notable Differences Between Geckos and Other Reptiles
Sticky Toed Climbing Ability
One of the most amazing things about geckos is their ability to climb virtually any surface, even smooth glass. This is due to special sticky pads on their toes that utilize van der Waals forces to adhere to surfaces.
No other lizards or reptiles have this ability, making geckos unique among reptiles for their climbing prowess. This allows them to inhabit environments that are inaccessible to other types of reptiles.
Nocturnal Activity Cycles
Unlike many lizards that are active during the day, geckos are primarily nocturnal. This means they sleep during the day and become active at dusk when they venture out to hunt for food. Their large eyes with vertical slit pupils are adapted for optimized night vision.
Other reptiles like iguanas, anoles, and agamas are active during daylight hours so they can bask in the sun’s warmth. The geckos’ nocturnal nature sets them apart in terms of their activity patterns.
Vocalizations
Geckos are one of the most vocal types of lizards, using various chirps and calls to communicate with each other. Many gecko species produce distinctive barking, clicking, or squeaking sounds. This is very different from other reptiles like snakes and turtles that are mute.
Some gecko calls are complex, like the tokay gecko’s vocalizations that function to define territory and attract mates. The wide range of vocal expressions used by geckos makes their communication abilities unique among reptiles.
Ability to Detach Tails
Geckos have specialized connective tissue planes that allow them to detach their tails when grasped by predators. Their tails continue to wiggle after detachment, distracting the predator while the gecko flees to safety. Within several weeks, the gecko can regenerate a new, albeit shorter, tail.
Other lizards like skinks and some iguanas also have this defense mechanism, but it is especially common in geckos. For example, day geckos of the Phelsuma genus are known to detach their tails readily when threatened.
This useful survival adaptation allows geckos to evade capture more easily than other reptiles.
Conclusion
In summary, while geckos may share some superficial similarities with amphibians like frogs and salamanders, they are definitively classified as reptiles, not amphibians. Geckos are terrestrial lizards with scaly skin, lack of gills or any aquatic stage of life, and evolutionary origins firmly within the reptile lineage.
So the next time you see a gecko patrolling your porch or peeking out from behind a window, you can confidently call it a reptile, not an amphibian.
We’ve covered the key anatomical, physiological, and behavioral differences that distinguish reptiles like geckos from amphibians. Geckos’ dry, watertight skin, lack of gills and complete life cycle on land sets them apart from moisture-dependent, semi-aquatic amphibians.
Understanding the evolutionary origins and taxonomic classification of geckos and other herptofauna provides deeper insight into the biodiversity of the animal world. If this article has piqued your interest in geckos and reptiles, further exploring topics like gecko reproduction, care as pets, or diversity across gecko species can lead to even more fascinating discoveries.
