Animal Diversity Web

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)

• Biogeographic Regions
• neotropical
  • 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. (Leen­ders, 2001; Sav­age, 2002)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

• Aquatic Biomes
• lakes and ponds
• rivers and streams

• Other Habitat Features
• riparian

• 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)

• Other Physical Features
• heterothermic

• 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)

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

• Key Reproductive Features
• seasonal breeding
• sexual
• oviparous

• 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)

• Parental Investment
• 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. (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)

• Key Behaviors
• arboreal
• cursorial
• terricolous
• diurnal
• territorial
• 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). (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

• Perception Channels
• visual
• tactile
• acoustic
• vibrations
• 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. (Fleet and Fitch, 1974; Sav­age, 2002)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • piscivore
  • insectivore
  • eats non-insect arthropods
• herbivore
  • folivore
  • frugivore
• 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. (Leen­ders, 2001; Lieber­man, 1980; Sav­age, 2002)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • raptors (Accipitridae)
  • opossums (Didelphidae)
  • large snakes (Serpentes)
  • white-nosed coatis (Nasua narica)

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)

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)

• Positive Impacts
• pet trade
• 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.

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

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

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.