Last Updated: Jun 17, 2015
Three basilisk lizard species, the common basilisk, emerald basilisk and brown basilisk live in Costa Rica, and are present in most major ecosystems and climate zones. They are also known as Jesus Christ lizards for their ability to run on the surface of water. Basilisks are not poisonous and are characterized by large and long bodies, compressed tails, and, in males, a fleshy crest.
Scientific Name: Basiliscus basiliscus
Status in the Wild: Common
Habitat: Rainforests, Tropical Dry Forests
Basilisk lizards belong to the genus Basiliscus, derived from the Greek word basiliskos for “little king.” The moniker may be attributed to a crown-like white mark on all basilisk lizards’ heads; others believe the Greek myth that it is named for the legendary basilisk, king of serpents that purportedly was able to turn enemies to stone with a single glance. Experts believe the former theory is likely correct, since all members of Basiliscus sport the white “crown.”
The lizard uses bipedal locomotion, arms held at its sides, to run at a velocity up to 4.8 feet/second for up to 66 feet. A basilisk can also swim very quickly, using skin flaps between its toes as flippers while its crest serves as a steering rudder. The lizard can also hop, run, and shimmy over sand, assuring it a quick getaway when in danger.
Basilisk lizards are omnivorous, consuming a variety of vegetation, insects, and even small invertebrates like bats. All three of Costa Rica’s basilisk species are diurnal, which means that they are active by day and sleep at night.
Basilisks Species in Costa Rica:
Common basilisk (Basiliscus basiliscus): This is the most common basilisk lizard found in Costa Rica. Adults range in size from one to almost three feet in length, weighing approximately 0.45 to 1.3 pounds. Their tales are long, accounting for 70-75% of their total length. Both males and females are neutrally colored, usually brown, dark olive, or bronze, with cream-colored bands and stripes. Males have a single head crest.
Brown basilisk (Basiliscus vittatus): This moderately sized basilisk lizard reaches almost two feet in length; its tail accounts for at least 75% of its size. True to their name, brown basilisk lizards are mostly brown in color, though some may have a dark olive coloration. This lizard also boasts light yellow and red stripes along its body. Adult males are easily identifiable, since they have a single triangular cephalic crest.
Emerald basilisk (Basiliscus plumifrons): This is a large basilisk species, growing up to three feet long. Their tales make up for 72-75% of their total length. Males of the species are unforgettable, characterized by their bright green coloration, red eyes, and turquoise blue spots on the dorsal ridge (chin area). Though they are not as impressive looking, female emerald basilisks are also bright green, making them easily distinguishable from other female basilisks. Male crests are bipartite, divided into a narrow anterior flap and a rounded, posterior midcephalic flap.
Basilisk lizards can be found throughout Costa Rica, particularly in lowland dry, lowland wet, premontane moist, and premontane wet forests.
Common basilisk: Occurring from southwestern Nicaragua to northwestern Columbia, common basilisk lizards are distributed along waterways on Costa Rica’s Pacific coast, from northern Guanacaste to the Osa Peninsula, and in inland Costa Rica near the Central Valley. They prefer lowland dry, moist and wet forests as well as premontane moist and wet forests, and can also be found in secondary forests.
Brown basilisk: Common in lowlands and premontane slopes from southern Mexico to northwestern Colombia, but never in southern Nicaragua, western Costa Rica, or southwestern Panama, this reptile has been introduced as a feral species in Florida. Brown basilisk lizards live in lowland moist and wet forests primarily along the Atlantic versant and Caribbean slope. There is a small population living south of the La Fortuna and Arenal area. They prefer open pastures and disturbed areas, and are especially common in coconut groves and other beach areas.
Emerald basilisk: Distributed throughout humid lowlands from Honduras to western Panama, emerald basilisk lizards live along Costa Rica’s south Pacific Coast, near Golfito and Palmar Sur, but generally do not live on the Osa Peninsula. They are also found in northern Costa Rica, near Turrialba and the Reventazon River, and along the Atlantic slope, from Tortuguero to the southern Caribbean. Emerald basilisks prefer lowland moist and wet forests, and are also found in premontane wet forest. They are most concentrated near streams and other small waterways, especially in areas with intact shore vegetation and trees.
Common Basilisk: In most cases, reproduction begins in March. Females lay five to eight clutches, or groups, of eggs over a period of ten months. Reproduction continues at a reduced rate in January and February. In very wet areas, reproduction is strong during the rains and tapers off during the drier season. Incubation lasts approximately ninety days; hatchlings measure about 1.6 inches and weigh just 0.07 ounces. Young females lay fewer eggs, reaching sexual maturity at about 20 months. Males also reach sexual maturity during their second year. Common basilisks generally live less than six years.
Brown Basilisk: Reproduction generally takes place from mid-February through October, though it continues at a slower pace during other times of year. Females lay four or five clutches annually; each egg group contains two to 18 eggs. Time to maturity is 50-70 days, when the hatchling will emerge, measuring 1.25 to 1.65 inches in length. Both males and females reach sexual maturity within six months. Brown basilisk lizards typically live for two years in the wild.
Emerald Basilisk: Reproduction takes place year-round but is most common during the Caribbean’s wetter season, from May through September. Egg clutches consist of four to 17 eggs, which will mature within 55-75 days. Hatchlings are 1.35 to 1.65 inches in length. Average lifespan is less than seven years.
Status in the Wild:
Basilisk lizards have many natural predators, most commonly birds of prey such as the great black hawk and the white hawk. Snakes, large fish, other reptiles, and mammals are also known predators. Basilisk lizards are not currently considered threatened or endangered.