There are a few different types of lizards that could be described as looking like snakes due to their elongated bodies and lack of legs. The most common examples are glass lizards, legless lizards, and slow worms. These reptiles have evolved snake-like appearances and behaviors as adaptations for burrowing and moving through vegetation and sand. Though they resemble snakes, they are actually lizards and have key differences in things like eyelids, ear openings, and head scales. Let’s take a closer look at these weird snake-looking lizards!
Glass Lizards
Glass lizards belong to the family Anguidae and are characterized by their shiny scales and highly breakable tails. There are around 200 species found throughout Europe, Asia, North America, and Central and South America. Some of the most well-known examples include the European glass lizard, Scheltopusik, and North American glass lizard.
These lizards entirely lack legs and have long, cylinder-shaped bodies that can reach up to 4 feet in length. Their limbs have been reduced to tiny vestiges covered by scales. Their snake-like shape allows them to move quickly through grass, sand, and loose soil and navigate narrow spaces.
One key difference between glass lizards and snakes is that glass lizards can autotomize, or voluntarily shed, their tails when threatened. The tail continues to wriggle after detachment, distracting predators while the lizard makes its escape. Their tails also regenerate over time.
Legless Lizards
Legless lizards have vestigial limbs like glass lizards but differ in lacking the ability to detach their tails. There are over 200 species found in the Americas, Asia, Africa, and Europe. Some examples are the California legless lizard, European legless lizard, and Brahminy blindsnake.
These lizards have paired flap-like front limbs that are concealed under scales and no rear limbs. Their snake-shaped bodies can reach up to 15 inches long. While their limbless condition limits them to a serpentine form of locomotion, some species have specialized scales on their bellies that provide traction for burrowing.
Legless lizards retain a small pelvic girdle connected to muscles that help them expel waste and reproduce. Unlike snakes, they also have movable eyelids, ear openings, and a fleshy tongue instead of a forked one.
Slow Worms
Slow worms belong to the Anguidae family like glass lizards. However, there are just 12 species, all found in Europe and Asia. The common slow worm is widespread in grasslands across Europe.
These lizards have lost their legs entirely over evolutionary time and superficially resemble smooth snakes. Adults reach lengths of 16 inches. Their slender, legless bodies allow them to secretively move through vegetation and underground burrows.
Slow worms have grooved scales that give them the appearance of an earthworm. Their scales also enable them to move by concertina locomotion, gripping surfaces on each side to inch forward. When threatened, they can shed their tails as a defense.
Unlike snakes, slow worms have movable eyelids, external ear openings, and a hinged jaw that cannot open widely enough to swallow large prey. They are also ovoviviparous, meaning they give birth to live young rather than laying eggs.
Shared Snake-Like Adaptations
Though not closely related, glass lizards, legless lizards, and slow worms have all evolved a serpentiform body as an adaption for a burrowing lifestyle. Their elongated, limbless shape provides several advantages:
- Allows them to navigate through narrow spaces and dense vegetation
- Increases speed and agility for catching prey or avoiding predators
- Distributes weight evenly for moving over loose sand or soil
- Provides camouflage in grassy or sandy environments
- Allows them to absorb heat efficiently when basking
Developing a snake-like profile has allowed these lizards to thrive in ground-dwelling niches by overcoming the constraints of limbs. However, they differ from true snakes in key ways that reflect their origins as lizards.
Differences Between Snake-Like Lizards and Snakes
While glass lizards, legless lizards, and slow worms exhibit snake-like appearances and behaviors, they lack defining characteristics of snakes:
- Snakes have a highly flexible jaw that allows them to swallow large prey whole. Legless lizards have a hinged jaw with limited gape.
- Snakes lack eyelids and external ear openings. Legless lizards have movable eyelids and ears.
- Snakes have a forked tongue used for sensing chemicals. Legless lizards have an unforked, fleshy tongue.
- Snakes shed their skin in one piece. Legless lizards shed their skin in patches.
- Snakes lack even vestigial limb elements. Some legless lizards retain reduced hip bones.
- Snakes are entirely carnivorous whereas some legless lizards are insectivorous or omnivorous.
These anatomical and physiological differences indicate legless lizards have separately evolved a serpentine body form to adapt to their environments, rather than sharing a common snake ancestor. Their snake-like profile is an example of convergent evolution.
Conclusion
Glass lizards, legless lizards, and slow worms provide fascinating examples of convergent evolution, where distantly related organisms independently evolve similar adaptations in response to similar environmental pressures. By converging on a snake-like morphology, these lizards can effectively hunt prey, escape predators, move through vegetation, and burrow underground within their ecological niches. However, key differences in things like their jaws, tongues, ears, and vestigial limbs reflect their evolutionary origins as lizards rather than snakes. So, while these limbless reptiles certainly resemble their serpentine neighbors, they represent a case of appearance matching lifestyle rather than indicating close relation!
Frequently Asked Questions
What are some examples of weird snake-looking lizards?
Some lizards that resemble snakes due to their legless, elongated bodies are glass lizards, legless lizards, slow worms, and scheltopusiks. These all belong to different lizard families but have converged on a serpentine form.
Why do some lizards look like snakes?
Legless lizards have evolved to look like snakes through the process of convergent evolution. Losing their limbs and elongating their bodies allows them to effectively burrow underground, move through vegetation, escape predators, and hunt prey within their ecological niches.
How can you tell these lizards apart from actual snakes?
While they look similar externally, legless lizards have key differences from snakes in their movable eyelids, external ear openings, unforked tongue, vestigial limb elements, ability to shed tails, and hinged jaw. These reflect their origins as lizards, not snakes.
Are legless lizards related to or descended from snakes?
No, legless lizards like glass lizards and slow worms have separately evolved to look like snakes through convergent evolution. They adapted a snake-like body shape to thrive in similar environmental niches, but remain biologically lizards.
What behaviors do these legless lizards share with snakes?
Like snakes, these lizards use serpentine locomotion to move through narrow spaces, lack limbs for burrowing, have camouflage to hide from predators, and can swallow prey whole (although with limitations due to their jaws).
Summary
Some lizards have evolved highly elongated, limbless bodies that resemble snakes. These include glass lizards, legless lizards, and slow worms. Their snake-like profile provides advantages for burrowing, hiding, and navigating through vegetation. However, they differ anatomically from snakes by having eyelids, ear openings, unforked tongues, and vestigial limbs, showing their separate evolutionary origins. These weird snake-looking lizards provide fascinating examples of convergent evolution and adaptations to similar ecological niches.