Costa Rica Reptiles – A Guide to Lizards, Snakes, and Crocodilians

Costa Rica’s world-renowned biodiversity extends deep into the realm of cold-blooded creatures, with a rich reptilian fauna of at least 228 species. This incredible diversity includes a vast array of lizards, geckos, skinks, snakes, marine and freshwater turtles, and imposing crocodilians. These animals have developed impressive adaptations to thrive in every corner of the country, from the high mountains to the coastal rainforests and the arid Guanacaste region.

While many lizards, like iguanas and basilisks, are diurnal and can be easily spotted basking in the sun, most snakes are nocturnal and elusive, making any sighting a special event. For those hoping to glimpse these fascinating animals, certain locations are legendary, such as the Río Tárcoles bridge, where massive crocodiles gather, or the beaches of Tortuguero and Ostional, which host spectacular sea turtle nesting events. This guide explores the most notable reptiles you may encounter on a journey through Costa Rica’s wildlands.

The “Jesus Christ Lizard” and Other Impressive Iguanians

Among the most visible reptiles are the lizards of the iguana family and their relatives. They are often seen perched on branches, fence posts, and riverbanks, soaking up the tropical sun.

Basilisks: The “Jesus Christ Lizard”

These lizards have earned their famous nickname for their remarkable ability to run upright across the surface of the water to escape predators. Young basilisks are particularly adept, capable of sprinting more than 50 feet across a pond or stream. Costa Rica is home to three distinct species:

• Double-crested Basilisk (Basiliscus plumifrons): This bright green lizard, which looks like a miniature dinosaur with its prominent head and back crests, inhabits the Caribbean lowlands and southwestern Costa Rica.
• Common Basilisk (Basiliscus basiliscus): A brown species with a similar crest, the Common Basilisk is found in the Pacific lowlands from Guanacaste down through the Osa Peninsula.
• Brown Basilisk (Basiliscus vittatus): Characterized by narrow white stripes on its face, this basilisk lives in the Caribbean lowlands, often in upland sites away from water.

These omnivorous lizards eat everything from insects and small fish to flowers and fruits. They are prolific breeders, laying multiple clutches of eggs throughout a nearly year-long breeding season.

Ctenosaurs and Green Iguanas

Two large lizards dominate the landscape and are often confused by visitors.

Feature	Ctenosaur (Ctenosaura similis)	Green Iguana (Iguana iguana)
Common Name	Black Iguana, Spine-tailed Lizard, “Garrobo”.	“Chicken of the Tree”.
Appearance	Tan and dark brown body; tail is ringed with large, pointed scales. Juveniles are bright green.	Green to gray body; a large, circular scale on the jaw; and a prominent dewlap (throat flap).
Habitat	Abundant on the Pacific slope in drier areas; often found basking on fence posts, rock piles, and roofs away from water.	Typically found in trees overlooking rivers, canals, and wetlands.
Diet	Omnivorous; diet shifts from mostly animal food when young to mostly plants as an adult.	Strictly vegetarian throughout its life, eating flowers, leaves, and fruits.

The Small and Swift: Anoles, Geckos, and Skinks

Beyond the large, dramatic lizards, the forest is teeming with smaller, swifter reptiles that play a crucial role in the ecosystem.

Anoles (Family Polychrotidae)

These small, slender lizards, with 21 species in Costa Rica, are a common sight on tree trunks and low shrubs. Males are known for their conspicuous territorial displays, where they bob their heads and extend a colorful throat fan called a dewlap. They are a primary food source for a host of predators, including birds like trogons and motmots, as well as vine snakes and even spiders. A few notable species include:

• Dry Forest Anole (Norops cupreus): Abundant in Guanacaste, it has a distinctive pink and bright orange dewlap.
• Lichen Anole (Norops pentaprion): This arboreal master of camouflage has a flattened body and loose skin that allows it to glide between trees like a flying squirrel.
• Slender Anole (Norops limifrons): This common rainforest species is notable for forming monogamous pair bonds, with the male and female often found moving through their territory together.

Geckos (Family Gekkonidae)

These mostly nocturnal lizards are masters of climbing, thanks to specialized pads on their toes.

• Turnip-tailed Gecko (Thecadactylus rapicaudus): The largest gecko in Costa Rica, it has a broad, swollen tail used for fat storage.
• Yellow-headed Gecko (Gonatodes albogularis): Unlike most geckos, this species is diurnal, with males sporting a bright yellow or orange head.
• House Gecko (Hemidactylus frenatus): An invasive species from Asia, this gecko is now common in tourist cabins, where its loud “chack” calls can be heard throughout the night.

The Serpents of Paradise: Snakes of Costa Rica

While a source of fear for some, snakes are a vital and fascinating part of the rainforest. Most are shy, nocturnal, and rarely encountered by travelers who stick to established trails.

Non-Venomous and Mildly Venomous Snakes

• Boa Constrictor (Boa constrictor): The country’s largest snake, this powerful reptile kills its prey by suffocation. It is highly adaptable and can be found in habitats ranging from dry forests to rainforests, sometimes even taking up residence in the rafters of buildings to hunt rodents.
• Vine Snakes (Oxybelis spp.): These pencil-thin snakes are incredibly camouflaged, mimicking vines as they hang from branches waiting for lizards and frogs.
• Chunk-headed Snake (Imantodes cenchoa): A nocturnal, arboreal snake with a disproportionately large head and thin body, it is a specialist in hunting sleeping anoles and frogs on foliage.

The Venomous Vipers (Family Viperidae)

These snakes are distinguished by their triangular heads, vertically elliptical pupils, and heat-sensing loreal pits between their eyes and nostrils.

• Fer-de-Lance (Bothrops asper): Known locally as terciopelo, this is the most dangerous venomous snake in Central America, responsible for the majority of snakebites. Its cryptic pattern provides excellent camouflage as it waits for prey along trails, often in agricultural areas like banana plantations.
• Eyelash Viper (Bothriechis schlegelii): This small, arboreal pit viper is named for the unique scales that protrude above its eyes. It comes in a variety of stunning color morphs, including green, rust, gray, and a brilliant golden-yellow (“oropel”).
• Bushmaster (Lachesis stenophrys): The largest pit viper in the Americas, this snake is extremely rare and shy, inhabiting only primary, undisturbed rainforests. It is the only New World pit viper that lays eggs.

Coral Snakes (Family Elapidae)

These brightly colored snakes are highly venomous but secretive and nocturnal, burrowing in the leaf litter. Their pattern of red, yellow, and black rings serves as a warning to predators. They can be distinguished from their harmless mimics, the False Coral Snakes, by a simple rhyme:

“Red on yellow, kill that fellow; red on black, friend of Jack”.

Ancient Mariners and River Dwellers: Turtles and Crocodilians

Costa Rica’s waterways and coastlines are home to some of its most ancient and impressive reptiles.

Sea Turtles

The country’s beaches are critical nesting grounds for several species of sea turtles.

• Leatherback Turtle (Dermochelys coriacea): The largest reptile in the world, the leatherback has a firm, leathery shell instead of a hard, bony one. One of its primary nesting beaches in the world is Playa Grande in Las Baulas National Park.
• Green Turtle (Chelonia mydas): The beach at Tortuguero National Park is one of the most significant nesting sites in the world for this species.
• Olive Ridley Sea Turtle (Lepidochelys olivacea): This is the most abundant sea turtle in Costa Rica, famous for its synchronized mass nesting events known as arribadas, where tens of thousands of females come ashore over a few days at beaches like Ostional and Nancite.

Crocodilians

Costa Rica has two crocodilian species, which can be distinguished by their snout shape.

• Spectacled Caiman (Caiman crocodilus): Smaller and alligator-like, the caiman has a broad, rounded snout and inhabits lowland wetlands, rivers, and even roadside ditches.
• American Crocodile (Crocodylus acutus): This much larger reptile can exceed 12 feet in length and has a more pointed snout with visible lower canine teeth. The most famous and accessible place to see them is from the bridge over the Río Tárcoles near Carara National Park, where dozens can be seen basking on the sandbars below.

From the tiny gecko hunting on a cabin wall to the giant leatherback turtle nesting on a moonlit beach, the reptiles of Costa Rica offer a profound connection to a wild and ancient world.

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Works Cited

Henderson, Carrol L. Mammals, Amphibians, and Reptiles of Costa Rica: A Field Guide. University of Texas Press, 2010.

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