Microlophus albemarlensisGalapagos Lava Lizard

Ge­o­graphic Range

Mi­crolo­phus albe­mar­len­sis (lava lizards), along with six other re­lated species, are found on Ecuador's Gala­pa­gos Is­lands. These dif­fer­ent species are be­lieved to have de­scended from a com­mon South Amer­i­can an­ces­tor. Lava lizards can be found on all major is­lands of the Gala­pa­gos but some species only oc­cupy cer­tain is­lands. Mi­crolo­phus albe­mar­len­sis can be found on all cen­tral and west­ern is­lands of the Gala­pa­gos. (Jack­son, 1985)

Habi­tat

Mi­crolo­phus albe­mar­len­sis lives in the low­land dry zones of the Gala­pa­gos Is­lands. Here the soil is loose and con­tains dry leaf lit­ter so that the lizards are able to bury them­selves in the soil at night. Rocks must also be abun­dant so that the lizards can hide un­der­neath them or in crevices for pro­tec­tion from the sun. The habi­tat is also cov­ered with flora such as cacti and vine­plants, which pro­vide shel­ter from the sun as well as food by at­tract­ing in­sects. Pop­u­la­tions of Mi­crolo­phus albe­mar­len­sis also de­crease as the low, dry land gives way to for­est. (Steb­bins, et al., 1967)

Phys­i­cal De­scrip­tion

Mi­crolo­phus albe­mar­len­sis has pri­mary fea­tures sim­i­lar to most other species of lizards. The males have dark bod­ies with yel­low-green mark­ings. Fe­males are red­dish brown in color with­out mark­ings. Fe­males also have red cheek patches when they reach ma­tu­rity dur­ing breed­ing sea­sons. Like most other lizards, both sexes ex­hibit changes in color de­pend­ing on mood. Col­oration also de­pends on where the lizards live. Those that live on dark lava are usu­ally darker than those that live on light sandy land. Males are gen­er­ally 2 to 3 times larger than fe­males. Adult males can range from 22 - 25 cm while fe­males range from 17 - 20 cm in length. Male dor­sal scales are more heav­ily keeled and have longer spines. De­spite the ob­vi­ous sex­ual di­mor­phism, it is hard to tell the sex of young Mi­crolo­phus albe­mar­len­sis be­cause ju­ve­niles re­sem­ble fe­males. (Jack­son, 1985; Steb­bins, et al., 1967)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • male more colorful
  • Range length
    17 to 25 cm
    6.69 to 9.84 in

De­vel­op­ment

In­cu­ba­tion of eggs takes about 3 months after which ba­bies hatch out of their shells 3 - 4 cm long. Males get their yel­low-green mark­ings when they reach sex­ual ma­tu­rity. Be­fore that, males are hard to dis­tin­guish from fe­males. Fe­males ma­ture much faster than males. Upon reach­ing sex­ual ma­tu­rity, fe­males may mate suc­cess­fully dur­ing the breed­ing sea­son and have a clutch of their own. (Jack­son, 1985)

Re­pro­duc­tion

Dur­ing mat­ing sea­son, males will en­gage in "push up" dis­plays to at­tract fe­males. This "push up" dis­play is also used to chal­lenge and in­tim­i­date other males who might be wan­der­ing into its ter­ri­tory look­ing for fe­males. When chal­lenged, the lizard will flat­ten out its side, lower its throat skin and as­sume the "push up" dis­play. Males will also fight using their tails and sides to slap at other com­pet­ing males. Fe­males' cheek patches will turn very red dur­ing breed­ing sea­sons as a sign to males that she is ready to mate. Male M. albe­mar­len­sis are not the most gen­tle of mates. They com­monly seize the fe­males by the skin, usu­ally at the neck, and drag them over a dis­tance be­fore cop­u­lat­ing. Suc­cess­ful males usu­ally have a harem as their ter­ri­tory over­laps with 2-4 other fe­males. How­ever, if the fe­male is not ready for mat­ing, she will ei­ther es­cape or may even chase the male away with a charge of her own. Fe­males also use odor to sig­nal that they are not in the mood to be both­ered. (Steb­bins, et al., 1967)

Breed­ing sea­son lasts from No­vem­ber to March. Here suc­cess­ful fe­males will lay a clutch of eggs, usu­ally 1-4, in a nest deep in the soil. Fe­males may breed every 3 to 4 weeks dur­ing the sea­son. The in­cu­ba­tion per­oiod of the eggs is about 3 months where young emerge about 3-4 cm in length. Males take about 3 years to reach sex­ual ma­tu­rity while fe­males only take 9 months. (Jack­son, 1985; Pri­eto, et al., 1976; Steb­bins, et al., 1967)

  • Breeding interval
    Every 3 -4 weeks during breeding season
  • Breeding season
    November to March
  • Range number of offspring
    1 to 4
  • Average number of offspring
    2
  • Average gestation period
    3 months
  • Average age at sexual or reproductive maturity (female)
    9 months
  • Average age at sexual or reproductive maturity (male)
    3 years

No avail­able in­for­ma­tion was found on parental care in this species.

Lifes­pan/Longevity

Mi­crolo­phus albe­mar­len­sis can live up to 10 years. (Jack­son, 1985)

  • Range lifespan
    Status: wild
    10 (high) years

Be­hav­ior

In gen­eral, lizards ap­pear when the sun rises (as early as 6am). Some lizards may start to for­age im­me­di­ately. The ac­tiv­ity of the lizards in­creases by mid-morn­ing when the ground starts to heat up rapidly. How­ever, by mid-day, when the tem­per­a­ture rises be­yond tol­er­a­ble lim­its, they re­treat from ex­posed po­si­tions to seek shel­ter under rocks, leaf lit­ter or plants. (Steb­bins, et al., 1967)

  • Range territory size
    129 to 378 m^2

Home Range

The av­er­age home range for male Mi­crolo­phus albe­mar­len­sis is around 378 square me­ters. While for fe­males its around 129 square me­ters. The home ranges of males usu­ally over­laps with sev­eral fe­males which he may court on a reg­u­lar basis. Males wan­der­ing into other male or even fe­male home ranges may be chased away. (Steb­bins, et al., 1967)

Com­mu­ni­ca­tion and Per­cep­tion

These lizards do not com­mu­ni­cate using any form of vocal com­mu­ni­ca­tion. Most of their com­mu­ni­ca­tion is through vi­sual dis­play be­cause vi­sion is their best-de­vel­oped sense. "Push up" dis­plays are used to ward off in­trud­ers as well as courtship com­mu­ni­ca­tion. Change of skin color can com­mu­ni­cate the mood of the lizard from fear to ag­gres­sion. Other ac­tions are used in­di­cate the in­ten­tions of in­di­vid­u­als. For ex­am­ple, fe­males are known to turn their back to males, raise their tail and shake it from side to side as a sign of re­jec­tion to ap­proach­ing males. It is also be­lieved that fe­males use odors to dis­suade male lizards dur­ing breed­ing sea­son. (Steb­bins, et al., 1967)

Food Habits

Mi­crolo­phus albe­mar­len­sis in the wild are mainly in­sec­ti­vores. They eat in­sects such as moths, flies, bee­tles, grasshop­pers and ants. They also feed on other arthro­pods like spi­ders and cen­tipedes. Geckos are some­times found in the stom­achs of these lizards. They eat plant ma­te­r­ial like cac­tus flow­ers if the weather is very dry and food is scarce. With man liv­ing in close prox­im­ity to these lizards, things such as bread crumbs, meat scraps and even mac­a­roni are eaten. This makes them fairly well-rounded om­ni­vores. (Jack­son, 1985; Steb­bins, et al., 1967)

  • Animal Foods
  • reptiles
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • leaves
  • seeds, grains, and nuts

Pre­da­tion

Mark­ings on lava lizards' bod­ies dif­fer de­pend­ing on the en­vi­ron­ment they live in, giv­ing them a form of cryp­tic pro­tec­tion against preda­tors. If the sur­round­ings are dark, their mark­ings will be darker. The same goes for light sur­round­ings. They can also drop their tails to dis­tract preda­tors long enough for them to es­cape. They can re­gen­er­ate their tails but it rarely grows back to its orig­i­nal length. Known preda­tors are hawks, snakes, mock­ing birds, herons, rats and feral cats. (Jack­son, 1985; Steb­bins, et al., 1967)

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

Since Mi­crolo­phus albe­mar­len­sis feeds mainly on a se­lec­tion of in­sects and other arthro­pods, they may be im­por­tant at keep­ing arthro­pod pop­u­la­tions in check. At times, seeds are found in the stom­achs of some lizards and in this way they may help dis­perse them through their drop­pings. A com­men­sal re­la­tion­ship is some­times ob­served when M. albe­mar­len­sis can be seen perched on the tails of Am­blyrhynchus crista­tus (ma­rine igua­nas) in order to eat small in­sects at­tracted to the igua­nas. (Steb­bins, et al., 1967)

  • Ecosystem Impact
  • disperses seeds
Species Used as Host

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Lava lizards are kept as pets in some homes. More im­por­tantly, they (like the finches of the Gala­pa­gos) are used to study evo­lu­tion of species in the form of adap­tive ra­di­a­tions. The 7 species of Mi­crolo­phus liv­ing on the is­lands have de­scended from a sin­gle, com­mon South Amer­i­can an­ces­tor, which is be­lieved to have floated to the Gala­pa­gos on drift-wood or other veg­e­ta­tion. (Steb­bins, et al., 1967)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse af­fects of Mi­crolo­phus albe­mar­len­sis on hu­mans.

Con­ser­va­tion Sta­tus

Mi­crolo­phus albe­mar­len­sis was not found on the IUCN red list of en­dan­gered species data­base. Its con­ser­va­tion sta­tus is thus un­known, al­though one web­site states that a species of lava lizard on the is­land of Santa María (Flo­re­ana) in the Gala­pa­gos, is being threat­ened by black rats and feral cats. ("In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources", 2002)

Con­trib­u­tors

Matthew Wund (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Tze Keong Chow (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, 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

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.
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.

fertilization

union of egg and spermatozoan

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

island endemic

animals that live only on an island or set of islands.

native range

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

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.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

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.

visual

uses sight to communicate

Ref­er­ences

In­ter­na­tional Union for Con­ser­va­tion of Na­ture. 2002. "In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources" (On-line ). The IUCN red list of En­dan­gered Species. Ac­cessed March 23 2003 at http://​www.​redlist.​org.

Car­pen­ter, C. 1977. The ag­gres­sive dis­plays of three species of South Amer­i­can iguanid lizards of the genus Tropidu­rus. Her­peto­log­ica, 33/3: 285.

Jack­son, M. H. 1985. Gala­pa­pa­gos: A Nat­ural His­tory Guide. The Uni­ver­sity of Cal­gary Press.

Pri­eto, A., J. Leon, O. Lara. 1976. Re­pro­duc­tion in the trop­i­cal lizard, Tropidu­rus hispidus. Her­peto­log­ica, 32/3: 319.

Steb­bins, R., J. Lowen­stein, N. Cohen. 1967. A field study of the lava lizard (Tropidu­rus albe­mar­len­sis) in the Gala­pa­gos Is­lands. Ecol­ogy, 48/5: 839.