Basiliscus basiliscus

Geographic Range

Common, or brown, basilisks are found on the Pacific slope of Central and northern South America from southwestern Nicaragua to northwestern Columbia.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Common basilisks are abundant in Pacific lowland forests of Central America and are the most commonly seen large lizards in western Costa Rica. They inhabit lowland dry, and moist forests, often adjacent to rivers and other waterways. They spend most of their time on the ground but sleep in perches up to 20 meters high at night.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Aquatic Biomes
• lakes and ponds
• rivers and streams

• Other Habitat Features
• riparian riparian

Physical Description

Adult common basilisks are large lizards (snout to vent length up to 203 mm) whose tails generally comprise 70 to 75% of total body length (total length to 800 mm). These large tails aid in balance. They are generally brown or olive in color but can range from bright green to olive-brown and bronze. They have darker cross bands and cream to yellow lip and lateral stripes. Juveniles are colored similarly to adults but are generally more vivid and also have three longitudinal stripes on the throat. All age classes have brown to bronze irises. They have long digits with sharp claws for climbing. Males are larger than females and have sail-like crests supported by elongate neural spines including a rounded or pointed head, dorsal, and caudal crest.

• Other Physical Features
• heterothermic heterothermic

• Sexual Dimorphism
• male larger
• sexes shaped differently
• ornamentation ornamentation

Development

Small female common basilisks grow faster than males of a similar size. Annual and seasonal factors seem to only affect the growth of females. Most females reach sexual maturity around 135 mm of length and males start to produce spermatozoa when they reach lengths of 131 mm.

Reproduction

Common basilisks begin breeding in March and females lay clutches of eggs over the next ten months. Females reach sexual maturity at around twenty months of age, males sometime in their second year of life. Males display size-related hierarchal dominance in which larger males often attack smaller males and prevent them from breeding. Because of this, many male basilisks do not enter the breeding cycle until 3 or 4 years of age. Male courtship behavior includes head-bobbing, which is typical of many iguanid lizards.

• Mating System
• polygynous polygynous

Breeding begins in March and females may lay several clutches of eggs (numbering 2 to 18 eggs per clutch) throughout the next ten months. Egg-laying is significantly lower in January, February, and March. Larger females lay more eggs than smaller ones.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• sexual sexual
• oviparous oviparous

A female common basilisk will dig a hole in which to lay her clutch of 2 to 18 eggs. After laying the eggs, she will usually inspect the nest, then fill it with soil using her forelimbs, packing the soil down with her snout. There is no further parental care.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • provisioning
    • female

Lifespan/Longevity

A captive basilisk lived over 9 years, but few would live this long in the wild. Most males live from 4 to 6 years of age, females most likely have shorter lives on average. Van Devender (1982) found that survivorship of hatchling females is significantly lower than hatchling males. First-year survival for hatchlings can be less than 60 percent. Annual adult survivorship difference may be as much as 60 percent for females and 40 for males, but it is estimated that these counts may have been biased due to greater emigration rates for males.

Behavior

Common basilisks are diurnal, spending most of their time foraging, basking, and resting along waterways. At night, they sleep in perches up to 20 m high. When disturbed or in the pursuit of prey, common basilisks will exhibit the behavior that earned the the nickname "Jesus Christ Lizard". Using erect bipedal motion, basilisks are able to run across the surface of water. Smaller individuals are more adept at this sprinting and may reach 20 or more meters on the surface. Larger lizards may sink and resort to swimming (or even diving) after just a few meters. Large feet and flattened toe pads also aid common basilisks in this behavior. The hind feet have large rolled-up scales that are pushed up when the lizard begins to cross the water. Male basilisks are territorial and will display head bobbing as a territorial threat.

• Key Behaviors
• arboreal arboreal
• cursorial
• terricolous
• diurnal diurnal
• territorial territorial
• dominance hierarchies dominance hierarchies

Home Range

There is no specific information available regarding home range size in common basilisks, though this characteristic appears to vary widely between basilisk species. A related species, Basiliscus plumifrons showed a home range of 1700 to 1900 square meters, with a standard deviation of approximately 1000 square meters. However, the range of another Basiliscus species, B. vittatus , has been documented to be much smaller (7.9 to 19.8 square meters).

Communication and Perception

Common basilisks have well-developed eyes and the sexual dimorphism that is found in this and several other Basiliscus species indicates that visual stimuli represent an important means of interspecific communication. The ears of common basilisks (and most other lizards) are also well-developed and serve similar functions to those of the mammalian ear (reception of sound waves, balance, orientation and movement of the head).

• Communication Channels
• visual visual

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

Food Habits

Common basilisks are omnivorous, though the diet of individuals in Panama indicated a significant preference for animal prey (22% plant material versus 78% animal material). They feed mainly on arthropods, small lizards, snakes, birds, mammals, fishes, freshwater shrimps, and occasionally frogs, but will also feed on flowers and fruits. Juveniles are more insectivorous than adults but will occasionally eat fishes. It has been shown that herbivory increases with age.

• Primary Diet
• carnivore carnivore
  • eats terrestrial vertebrates
  • piscivore piscivore
  • insectivore insectivore
  • eats non-insect arthropods
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore
• omnivore omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• insects
• terrestrial non-insect arthropods
• aquatic crustaceans

• Plant Foods
• fruit
• flowers

Predation

Hatchling iguanids, including common basilisks, are readily eaten by raptors. Lizards such as giant ameivas ( Ameiva ameiva ) prey on common basilisk eggs, and many mammalian predators undoubtedly eat the eggs as well. Opossums and snakes may prey on adult basilisks while they are sleeping at night. The basilisk's brown or green-olive color probably helps to camouflage the lizard in the branches of trees and shrubs.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

As generalist omnivores, common basilisks prey on many species. They are also a prey species for a handful of top level predators (see predators). Common basilisks in Panama were found to be hosts for the microbial parasites Plasmodium basilisci and P. achiotense .

Economic Importance for Humans: Positive

Basilisks are popular pets and some people travel to certain areas to see the famous "Jesus Christ Lizard".

• Positive Impacts
• pet trade pet trade
• ecotourism ecotourism

Economic Importance for Humans: Negative

These lizards do not harm human interests.

Conservation Status

Common basilisks are common throughout their range and face no immediate threats to current populations. Continued habitat destruction in tropical regions represents the most significant conservation threat to this species.

Additional Links

Encyclopedia of Life

Contributors

Alyssa Wethington (author), Michigan State University, James Harding (editor), Michigan State University, Jeremy Wright (editor), University of Michigan-Ann Arbor.

References

Fleet, R., H. Fitch. 1974. Food Habits of Basiliscus basiliscus in Costa Rica. Journal of Herpetology , 8:3: 260-262.

Krysko, K., J. Seitz, J. Townsend, K. Enge. 2006. The Introduced Brown Basilisk (Basiliscus vittatus) in Florida. Iguana , 13: 25-30.

Leenders, T. 2001. A Guide to the Amphibians and Reptiles of Costa Rica . Miami, Florida: Distribuidores Zona Tropical, S.A..

Lieberman, A. 1980. Nesting of the Basilisk Lizard (Basiliscus basiliscus). Journal of Herpetology , 14:1: 103-105.

Savage, J. 2002. The Amphibians and Reptiles of Costa Rica . Chicago: The University of Chicago Press.

Telford, S. 2007. Malarial Parasites of the “Jesu Cristo” Lizard Basiliscus basiliscus (Iguanidae) in Panama. Journal of Eukaryotic Microbiology , 19:1: 77-81.

Van Devender, R. 1982. Growth Ecology of a Tropical Lizard, Basiliscus basiliscus. Ecology , 59:5: 1031-1038.

Vaughan, C., O. Ramirez, G. Herrera, E. Fallas, R. Henderson. 2007. Home range and habitat use of Basiliscus plumifrons (Squamata: Corytophanidae) in an active Costa Rican cacao farm. Applied Herpetology , 4: 217-226.

Zug, G., L. Vitt, J. Caldwell. 2003. Herpetology, 2nd Edition . London, U.K.: Academic Press.

World Association of Zoos and Aquariums. 2011. "Common Basilisk" (On-line). World Association of Zoos and Aquariums. Accessed November 04, 2011 at http://www.waza.org/en/zoo/pick-a-picture/basiliscus-basiliscus .