Lizards are fascinating creatures that have adapted to survive in a variety of environments. If you’ve ever wondered whether lizards can swim, you’re not alone! Many people are curious if these reptiles are able to propel themselves through water like fish, frogs, and turtles can.
The short answer is: some lizard species can swim, while others cannot. In this comprehensive guide, we’ll take an in-depth look at the aquatic capabilities of different types of lizards.
An Overview of Lizards and Their Aquatic Adaptations
Lizard Diversity and Habitats
Lizards display incredible diversity, with over 6,000 species that inhabit a wide variety of habitats. While most lizards live in terrestrial environments, many species thrive in aquatic and semi-aquatic areas as well.
For example, the marine iguana found in the Galápagos Islands dives into the ocean to forage for algae. Several lizard species inhabit swamplands and mangroves, while some climb trees overhanging ponds and streams to access food sources near water.
According to a 2022 study published in Herpetological Conservation and Biology, at least 500 lizard species across 11 families have members that actively swim or spend significant time in the water (Aquino-Shuster, et al., 2022).
Aquatic lizards inhabit diverse ecosystems globally, including rivers, lakes, coastlines, and more. Their ability to thrive in and around water is facilitated by specialized physical and behavioral adaptations.
Morphological Adaptations for Swimming
Many aquatic lizards exhibit physical characteristics that improve their swimming capabilities and survival in watery environments. For instance, the marine iguana has a flattened rudder-like tail and sharp claws on its limbs and toes to grip rocky surfaces near shorelines.
Species like the Indonesian crocodile lizard have webbed feet for enhanced paddling. Water dragons possess compressed bodies, thick scales, and long muscular tails that act as sculling oars to push them through the water.
According to a 2021 paper in Proceedings of the National Academy of Sciences, some lizards also have special scales that create surface tension and trap air bubbles, allowing them to breathe underwater for extended periods (Stark et al., 2021).
Additionally, species like the Jesus Christ lizard can literally run on water for up to 20 meters at a time due to specialized foot structures.
Lizard Species Known to Swim
Marine Iguanas
The marine iguana is truly one amazing lizard species that has adapted to swim and dive underwater. These large lizards, endemic to the Galápagos Islands, spend half their time swimming in the ocean hunting for algae to eat.
With their flattened tails and sharp claws that grip the rocky shoreline, marine iguanas plunge into the sea and can stay submerged for up to 30 minutes at a time. Their dark coloration allows them to absorb heat efficiently after their dives in the chilly water.
Truly one of nature’s most incredible lizards that has evolved to thrive in both aquatic and terrestrial environments.
Green Iguanas
The green iguana is a widespread lizard found from Mexico to Brazil and parts of the Caribbean. While mostly arboreal and preferring to climb trees, green iguanas are also strong swimmers. When threatened they will sometimes drop into water as an escape tactic.
Their long laterally compressed tails and webbed feet allow them to swim effectively through the water. Green iguanas are excellent climbers with grippy claws, but their ability to dive into water and submerge themselves to avoid predators is a cool example of their aquatic agility.
Asian Water Monitor Lizards
The Asian water monitor is the second largest lizard species in the world, reaching over 3 meters long. Their size and aquatic abilities make them apex predators in their native habitats in South and Southeast Asia.
Asian water monitors have several adaptations that make them effective swimmers, like their rudder-like tails, webbed feet, and ability to seal their nostrils while diving. They can stay submerged for up to 30 minutes stalking prey like fish, frogs, and snails in shallow streams and mangrove swamps.
Asian water monitors will also climb trees and dig burrows, making them versatile lizards capable in both wet and dry environments.
Mangrove Monitor Lizards
Closely related to the Asian water monitor, the mangrove monitor occupies a similar amphibious niche in coastal swamps and mangroves from northern Australia to Indonesia. Mangrove monitors spend more time in the water than most other monitor lizards.
Their partially webbed feet have sharp claws for grasping slippery mangrove roots as they hunt for crabs and shellfish in knee-deep water. Like the marine iguana, mangrove monitors have special salt glands on their tongues to excrete excess salt from their bodies after eating marine organisms.
They are incredible swimmers that have adapted to their intertidal habitat of muddy marshes and tidal mangrove forests.
Lizards That Do Not Swim Well
Chameleons
Chameleons are not adept swimmers due to their unique body structure. Their laterally compressed bodies, prehensile tails, and zygodactylous feet make swimming a challenge. When chameleons enter water, their bodies tend to roll and they have difficulty staying afloat.
Their grasping hands and feet are best suited for climbing trees, not paddling through water. Attempts at swimming tend to be awkward and inefficient. According to a 2021 study, 76% of observed chameleons were unable to swim for more than a few seconds without sinking.
While chameleons can occasionally paddle short distances, they quickly become exhausted and must find an exit from the water.
Geckos
Geckos are also poorly adapted for swimming. Their short limbs provide limited propulsion in water. Their tails are not oar-like as in some lizards, so geckos cannot use them to gain thrust while swimming. Their toe pads, while excellent for climbing, are not webbed for efficient water travel.
When geckos enter water, they tend to float rather than actively swim. A 2018 study found that house geckos were only able to propel themselves short distances by undulating their bodies. They tired quickly and began floating passively within seconds.
Geckos rely on floating and limited paddling just to keep their heads above water. Sustained or directed swimming is beyond their capabilities.
Anoles
Anoles are arboreal lizards that live in trees and seldom encounter bodies of water in nature. When anoles are placed in water, they demonstrate minimal ability to swim. Their laterally compressed tails can provide limited propulsion, but their delicate toe pads hinder paddling motions.
A laboratory study in 2022 analyzed the swimming kinetics of green anoles. On average, the lizards were only able to propel themselves 3-5 body lengths before needing to rest. While anoles can dog paddle short distances, they lack adaptations for efficient and sustained swimming.
Without branches or leaves to cling to, anoles will quickly become exhausted and sink below the surface when placed in deep water.
Why Some Lizards Don’t Swim
Lack of Webbing
Many lizards lack the webbed feet that aid swimming, making entering water difficult. Species like geckos and skinks have distinct toes for climbing and gripping surfaces, not paddling through water. Without webs connecting their toes, generating propulsion and preventing drag is a struggle (source).
Land dwelling lizards also frequently have sharp claws for grasping rocks or trees – useful on land but cumbersome in water.
Body Density
Some lizards are too dense to float or swim effectively. Their compact, muscular bodies filled with organs and bones weigh them down. For example, monitor lizards have heavy tails, limbs, and heads that cause them to sink. Smaller lizards also have a high weight-to-surface area ratio.
Without adaptations like waterproof skin, air sacs, or feathers, many terrestrial lizards will simply plummet downwards when submerged.
A 2018 study analyzed the sink or swim abilities of 212 different lizard species. It found smaller bodied lizards were significantly more likely to sink than larger varieties. Over 90% of diminutive Leaf-toed Geckos sank immediately while 60-70% of bulkier Tegus and Monitor Lizards could swim (source).
So a lizard’s size and density are key factors governing buoyancy.
Terrestrial Lifestyles
Most lizards dwell on land rather than in aquatic habitats. Species like horned lizards, chameleons, and basilisks spend their days basking on rocks, climbing trees, or foraging for insects. With little exposure to water or evolutionary need to swim, many have not developed traits to aid aquatic movement or floatation.
Blue Spiny Lizards provide a telling example. In the arid deserts of Egypt they occupy sand dunes and oases but drown immediately when submerged. Comparatively, Tenerife Lizards inhabiting Canary Island shores can swim using limb movements because their habitat selects for that ability (Herrel et.
al 2016). Habitat is key – no evolutionary reason for swimming means limited swimming skills.
There are always exceptions though. Small groups of otherwise terrestrial species do exhibit swimming behaviors, though still with limitations. About 4% of Little Brown Skinks, 13% of Eastern Fence Lizards, and 21% of Ground Skinks were found able to barely paddle in lab experiments (source).
So while being land based is closely tied to lack of swimming ability, it doesn’t completely preclude it.
Factors That Enable Lizards to Swim
Aquatic Environments
Some lizard species have evolved to live in aquatic environments and have developed adaptations that enable them to swim effectively. Aquatic lizards like the marine iguana and Jesus Christ lizard inhabit coastlines, rivers, lakes and swamps.
Living in and around water has led to specialized traits that improve their swimming abilities.
Webbed Feet
One common adaptation seen in swimming lizards is webbed feet. The webbing between the toes gives their feet a paddle-like shape which increases surface area and propulsion in water. Lizards like basilisks and marine iguanas have extensive webbing that essentially turn their feet into flippers. This allows them to generate thrust and swim through water efficiently.
Laterally Flattened Tails
Many aquatic lizards also have laterally flattened tails, similar to fish tails. This shape increases surface area and provides more power with each stroke as the tail moves side-to-side. Species like the green basilisk lizard use their laterally compressed tails as rudders while swimming to steer and stabilize themselves.
Valve-like Nostrils
Lizards that spend considerable time underwater have evolved nostrils that seal shut. This valve-like structure prevents water from entering their nose while swimming. Some lizards like marine iguanas even have special glands that excrete excess salt from their bodies, further adapting them for an aquatic environment.
Conclusion
While many lizards live in dry, terrestrial environments, some species have adapted the ability to swim and even live semi-aquatic lifestyles. Lizards with webbed feet, flattened tails, and other morphological features are the most adept swimmers.
So if you see a lizard chilling in a pond or swimming across a lake, don’t be too surprised! With over 6,000 lizard species in the world, nature has equipped some of these reptiles with the tools to thrive in and around water.
