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Basiliscus basiliscusCommon Basilisk

By Alyssa Wethington

Geographic Range

Common, or brown, basilisks are found on the Pacific slope of Central and northern South America from southwestern Nicaragua to northwestern Columbia. (Leenders, 2001; "Common Basilisk", 2011)

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. (Leenders, 2001; Savage, 2002)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • Range elevation
    0 to 600 m
    0.00 to 1968.50 ft

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. (Leenders, 2001; Savage, 2002; "Common Basilisk", 2011)

  • Sexual Dimorphism
  • male larger
  • sexes shaped differently
  • ornamentation
  • Range mass
    200 to 500 g
    7.05 to 17.62 oz
  • Range length
    430 to 800 mm
    16.93 to 31.50 in
  • Average length
    520 mm
    20.47 in

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. (Van Devender, 1982)

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. (Leenders, 2001; Savage, 2002; Van Devender, 1982; "Common Basilisk", 2011)

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. (Leenders, 2001; Savage, 2002; Van Devender, 1982)

  • Breeding interval
    Common basilisks begin breeding in March of every year.
  • Breeding season
    Breeding in March, egg-laying in following ten months.
  • Range number of offspring
    2 to 18
  • Range gestation period
    60 to 90 days
  • Average age at sexual or reproductive maturity (female)
    20 months
  • Average age at sexual or reproductive maturity (male)
    2 years

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. (Leenders, 2001; Lieberman, 1980; "Common Basilisk", 2011)

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. (Leenders, 2001; Savage, 2002; Van Devender, 1982)

  • Range lifespan
    Status: wild
    7 (high) years
  • Range lifespan
    Status: captivity
    9 (high) years
  • Typical lifespan
    Status: wild
    2 to 6 years

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. (Savage, 2002; "Common Basilisk", 2011)

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). (Krysko, et al., 2006; Vaughan, et al., 2007)

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). ("Common Basilisk", 2011; Zug, et al., 2003)

  • Communication Channels
  • visual

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. (Fleet and Fitch, 1974; Savage, 2002)

  • 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. (Leenders, 2001; Lieberman, 1980; Savage, 2002)

  • Anti-predator Adaptations
  • 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. (Telford, 2007)

Commensal/Parasitic Species
  • Plasmodium basilisci
  • Plasmodium achiotense

Economic Importance for Humans: Positive

Basilisks are popular pets and some people travel to certain areas to see the famous "Jesus Christ Lizard". ("Common Basilisk", 2011)

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.

Contributors

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

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

piscivore

an animal that mainly eats fish

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

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.

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.

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