Anolis carolinensis

Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Cladus: Unidentata Episquamata Toxicofera
Subordo: Iguania

Familia: Dactyloidae
Subfamiliae: Anolinae
Genus: Anolis
Species: A. carolinensis
Subspecies: A. c. carolinensis – A. c. seminolus
Name

Anolis carolinensis (Voigt, 1832)
Synonyms

Anolis bullaris Daudin 1802: 69 (part.)
Dactyloa (Ctenocercus) carolinensis — Fitzinger 1843: 68
Anolis principalis Gray 1845: 202
Lacerta principalis
Anolis carolinensis Duméril & Bibron 1837: 120
Anolis baccatus Bocourt, 1873

References

Voigt, F. S. 1832. Das Thierreich, geordnet nach seiner Organisation: als Grundlage der Naturgeschichte der Thiere und Einleitung in die vergleichende Anatomie 2: 71.
Duméril, A. M. C. & Bibron, G. 1837. Erpétologie Générale ou Histoire Naturelle Complete des Reptiles. Vol. 4. Libr. Encyclopédique Roret, Paris, 570 pp.
Köhler, G. 2011. Taxonomic status of Anolis baccatus Bocourt 1873 (Reptilia, Squamata, Polychrotidae). Zootaxa 3015: 61–65. Preview

Vernacular names
български: Зелен анолис
čeština: Anolis rudokrký
dansk: Grøn anole
Deutsch: Rotkehlanolis
English: Carolina Anole
فارسی: آنول کارولینا
français: Anole vert
magyar: Zöld anolisz
italiano: Anolide della Carolina
日本語: グリーンアノール
한국어: 녹색아놀도마뱀
Nederlands: Roodkeelanolis
polski: Anolis zielony
română: Anolisul verde
русский: Североамериканский красногорлый анолис
svenska: Grön anolisödla
українська: Аноліс каролінський
Tiếng Việt: Thằn lằn Carolina

Anolis carolinensis (US: /əˈnoʊ.li/ (About this soundlisten)) or green anole (among other names below) is a tree-dwelling species of anole lizard native to the southeastern United States and introduced to islands in the Pacific and Caribbean. A small to medium-sized lizard, the green anole can change its color to several shades from brown to green.

Other common names include the Carolina anole, Carolina green anole, American anole, American green anole, North American green anole and red-throated anole. It is sometimes referred to as the American chameleon (typically in the pet trade) due to its color-changing ability, however it is not a true chameleon.

Description

The green anole is a small to medium-sized lizard, with a slender body. The head is long and pointed with ridges between the eyes and nostrils, and smaller ones on the top of the head. The toes have adhesive pads to facilitate climbing. They exhibit sexual dimorphism, the males being fifteen percent larger. The male dewlap (throat fan) is three times the size of the female's and bright red, whereas that of the female is lighter in color, ranging from white to pale pink.[3] Males can extend a pronounced dorsal ridge behind the head when displaying or when under stress. Females have a prominent white stripe running along their spine, a feature most males lack.

Adult males are usually 12.5–20.3 cm (4.9–8.0 in) long, with about 60-70% of which is made up of its tail, with a body length up to 7.5 cm (3.0 in) and can weigh from 3–7 g (0.11–0.25 oz).[3][4][5][6]
Coloration and color morphs
Contrasting colors. The prominent white dorsal stripe is characteristic of females.
Anolis carolinensis on Star Jasmine, South Carolina, demonstrating camouflage

Colour varies from brown to green and can be changed like many other kinds of lizards, but anoles are closely related to iguanas[7] and are not true chameleons. Although A. carolinensis is sometimes called an 'American chameleon', true chameleons do not naturally occur in the Americas, and A. carolinensis is not the only lizard currently in its area of distribution capable of changing colour. In contrast, many species of true chameleons display a greater range of color adaptation, though some can hardly change color at all.[3][8]

The typical coloration for a green anole ranges from the richest and brightest of greens to the darkest of browns, with little variation in between. The color spectrum is a result of three layers of pigment cells or chromatophores: the xanthophores, responsible for the yellow pigmentation; cyanophores, responsible for the blue pigmentation, and melanophores, responsible for the brown and black pigmentation. The anole changes its color depending on mood, level of stress, activity level and as a social signal (for example, displaying dominance). Although often claimed, evidence does not support that they do it in response to the color of the background (camouflage).[9][10] Whether they do it in response to temperature (thermoregulation) is less clear, with studies both supporting it[11] and contradicting it.[12] Changing color while under a sharply contrasting shadow can cause a "stencil effect", where the outline of the shadow is temporarily imprinted in the animal's coloration (see image in gallery, below). When stressed—while fighting, for example—the skin just behind the lizard's eyes may turn black independently from the rest of the animal's coloration, forming "postocular spots."

A lack in one of the pigment genes causes color exceptions. These color mutations are also called phases. The rare blue-phased green anole lacks xanthophores, which results in a blue, rather than red, often pastel blue, anole. These specimens have become popular recently in the pet trade market. When the anole is completely lacking xanthophores, it is said to be axanthic and the animal will have a completely pastel- or baby-blue hue. They are extremely rare—usually produced in one of every 20,000 individual anoles in the wild. Another phase is the yellow-phased green anole, which lacks cyanophores. Colonies of these rare color-phased anoles have been reported, but anoles with these color mutations rarely live for long, since the green color provides camouflage for hunting down prey, as well as hiding from predators.
Taxonomy

Anolis carolinensis is a species of the large lizard genus Anolis within the family Dactyloidae (anole lizards). Within the genus, thirteen species have been identified as a distinct clade, referred to as the Anolis carolinensis series. This group are mid-sized trunk crown anoles with large conspicuously elongated heads and extreme levels of sexual dimorphism. The species was named by Friedrich Siegmund Voigt (1781 - 1850) in 1832.[2]
Distribution and habitat

This species is native to North America, where it is found mainly in the subtropical southeastern parts of the continent. Anoles are the most abundant on the Atlantic Coastal Plains in North Carolina, South Carolina, Georgia and Florida, and on the Gulf Coast in Alabama, Mississippi, Louisiana, and Texas, where they extend inland as far as Texas Hill Country and the DFW Metroplex; they have also been recorded in Tamaulipas, Mexico, but it is mostly likely an introduction. In the Carolinas, they are found on the coastal plains as far north as False Cape in Virginia,[13] and in the southern piedmont of North Carolina, but throughout South Carolina,[8] while in Georgia they are widespread except in the Blue Ridge region.[3]

The species has been introduced into various locales in the Pacific and the Caribbean: Hawaii, the Ogasawara Islands, the Northern Mariana Islands, the Bahamas, Anguilla, Palau, and Saint Vincent and the Grenadines, as well as the Canary Islands. They have been sighted in Orange County and San Diego County of southern California, with sightings in San Diego going at least as far back as 1993.[14]

A. carolinensis is arboreal in nature but may be seen on the ground and frequently seen on shrubs in the low country of the Carolinas, but is also a common sight in urban areas on steps and railings, adjacent to foliage. It is common on roadsides, the edges of forests where there are shrubs and vines, but also building sites having abundant foliage and sunlight. Their preferred habitat is moist forests and brushy clearings.[3][8]
Conservation

Carolina anole males that encounter rival males frequently find it is an introduced and invasive brown anole (Anolis sagrei, also known as the Bahaman anole). When browns first appeared in the United States in the early 1900s,[15] the Carolinas ceded their ground-level territories and were relegated to a very different ecosystem high in the treetops. On occasion, a more aggressive Carolina anole may be seen closer to the ground and in competition with the brown anoles.

Currently A. carolinensis is abundant in its area of distribution, and is able to thrive in disturbed areas, so it is not considered threatened; but the brown anole represents a developing threat in the future.[3]
Behavior
Male Carolina anoles fighting, exhibiting pronounced dorsal ridge signalling aggression, and black postocular spots behind the eyes, indicating stress
Anole displaying at its reflection
Carolina anole licking

Male anoles are strongly territorial creatures. Some have even been witnessed fighting their own reflections in mirrored glass. The male will fight other males to defend his territory.[16] On sighting another male, the anole will compress his body, extend the dewlap, inflate a dorsal ridge, bob his head and attempt to chase the rival away. If the rival male continues to approach, anoles will fight by biting and scratching each other. Serious injury is rare, but males often carry numerous scars on their head and face, especially during the mating season. Their territory, which is about 1 m3 (35 cu ft), usually includes two to three females.[3][8]

The Carolina anole is diurnal and active throughout the year, peaking in spring and fall. Winter activity is dependent on sun and temperature.[3]
Diet
Male Carolina anole eating a dragonfly. Note the inflated dorsal ridge

An anole's diet consists primarily of small insects such as crickets, grasshoppers, flies, butterflies, moths, cockroaches, small beetles, and other arthropods, including spiders, as well as occasionally feeding on various grains and seeds[3][8] Although anoles have been observed preying upon smaller reptiles such as juvenile skinks, this is not thought to be typical behavior.[3] Many people who keep these lizards as pets feed them mealworms, grubs, maggots, and small crickets.
Predators

Major predators include the broadhead skink, snakes, birds, and in urban habitats, cats. Like many lizards, anoles display autotomic tails, which wriggle when broken off. This distracts the predator and helps the anole to escape. A new tail then starts to develop.[3] The new tail, however, containing cartilage rather than bone, will typically not grow back to the same length as the first one, and may exhibit a marked difference in color and texture from the rest of the animal.

Anoles are parasitized by some species of sarcophagid flies, including Lepidodexia blakeae.[17] Adult flies will deposit eggs on live anoles, and the fly larvae develop inside the lizard until they emerge from a wound and pupate into adult flies in sediment. Infection is often fatal, with mortality rates possibly as high as 90%.[17]
Reproduction
Carolina anoles mating

The typical breeding season for Carolina anoles starts as early as April and ends in late September, gonadal activity being largely regulated by photoperiod, enlarging in spring as the weather warms up and days lengthen, and then regressing in late summer.[3][8]

During this time, the males patrol their territory and the most brilliant displays of these creatures can be seen. Males defend their territory and females from rivals, while courting the females with elaborate displays of extending their brightly colored dewlaps while bobbing up and down, almost doing a dance.[18] The dewlap is also used to ward off other males. The male courts and pursues a female until the two successfully mate. Usually, when the female is ready to mate, she may let the male catch her, at which point he will grasp her by biting a fold of her skin behind her neck. The male will then position his tail underneath the female's tail near her vent. Males have two sex organs, known as hemipenes, which are normally kept within the body, but are everted from his vent for mating. Males seem to alternate between the left and right hemipenis on successive matings.[19]

The female matures one ovarian follicle at a time, the ovaries alternating in production. The sight of a courting male induces ovarian development, sexual receptiveness and then ovulation. About two to four weeks following mating, the female lays her first clutch of eggs, usually one or two in the first clutch. She can produce an egg every two weeks during the breeding season, until about 10 eggs have been produced. However, she can store sperm for up to eight months following mating. She then buries the soft-shelled eggs in a shallow depression in soft soil, leaf litter, compost, rotting wood, or even a hole in a nearby tree. Eggs average 12.5 mm (0.49 in) by 9.3 mm (0.37 in) in size.[3]

The eggs are left to incubate by the heat of the sun, and if successful, will hatch in about five to seven weeks (30–45 days) from late May to early October. The incubate temperature has to be 80 to 85 degrees Fahrenheit. On hatching, the hatchlings are 52–67 mm (2.0–2.6 in) in length.[3][8]

The hatchlings must fend for themselves, as they are not cared for by either parent. The young hatchlings must be wary of other adult anoles in the area, as well as larger reptiles and mammals, which could eat them. Younger anoles differ from adults in having less obvious head ridges, a wider head and shorter tail. They mature in about eight months.[3]
Juvenile male
Captivity

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Carolina anoles' nervous natures makes it advisable not to attempt to handle them very often; despite this, Carolina anoles are popular pets. Individual animals may or may not adapt readily to cage life. Care must be taken to ensure the animals receive the support they need to adapt to captivity and live full and enriching lives; an adequately sized enclosure, as well as the appropriate plants and substrate material, are beneficial to the health of captive Carolina anoles.

Carolina anoles can live in a 20-gallon or larger terrarium, with numerous plants lining the back and sides of the cage. A typical set-up would include an arena in which feeder insects, appropriately fortified with calcium supplements, can be dropped in clear view of the lizards. Carolina anoles like to leap down on potential prey and engulf it.

Although Carolina anoles are not overly social animals, in the wild they do interact with their neighbors and form loose clans. This can be successfully translated into captive life, with several females kept together in the same enclosure, although the more lizards are kept, the larger the tank must be. However, having more than one adult male in a tank will inevitably lead to territorial disputes and fighting regardless of the enclosure's size, resulting in increased stress for all the animals in the cage.

Pet-owners are advised to leave a heat light over some of the highest plants so the reptiles can bask directly below it. In the wild, anoles drink by lapping water droplets off of leaves; thus, water is best administered with a mist bottle, as the lizards may ignore a water dish even after becoming severely dehydrated. As with all reptiles, it is important to keep the temperature and humidity of their environment within their comfort zones.
Genomics

This species has been chosen as a model reptile for genomics by the National Human Genome Research Institute genome sequencing program.[20] It was selected because of the ease and low cost of laboratory breeding and evolutionary value of the diversity of the genus.[21] In 2011, the complete genome of this lizard was sequenced and published in Nature.[22] Before its genome was published, only mammals and three bird species had been sequenced among amniotes.[23] The draft genome sequence is 1.78 Gb (compared with 2.0–3.6 Gb mammalian and 0.9–1.3 Gb avian genome assemblies), of which 27% are mobile elements such as LINEs. A total of 17,472 protein-coding genes and 2,924 RNA genes were predicted from the A. carolinensis genome assembly.[24]

References

Frost, D.R. & Hammerson, G.A. 2020. Anolis carolinensis. The IUCN Red List of Threatened Species 2020: e.T64188A18972474. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T64188A18972474.en. Downloaded on 12 March 2021.
Voigt F.S. 1832: In Cuvier`s Das Thierreich, geordnet nach seiner Organisation: als Grundlage der Naturgeschichte der Thiere und Einleitung in die vergleichende Anatomie, Vol. 2: 71.
John B. Jensen. Amphibians and Reptiles of Georgia. University of Georgia Press, 2008. Green Anole p. 296. ISBN 0820331112
Savannah River Ecology Laboratory
Animal Diversity Web, p. 1
Animal Diversity Web, p. 2
NCBI Taxonomy Browser
Amphibians and Reptiles of the Carolinas and Virginia. Bernard S. Martof, Julian R. Harrison, III, William M. Palmer, Joseph R. Bailey. University of North Carolina Press, 1989. ISBN 0807842524
Jenssen; Greenberg; Hovde (1995). "Behavioral profile of free-ranging male Anolis carolinensis across breeding and post-breeding seasons". Herpetol. Monographs. 9: 41–62. doi:10.2307/1466995. JSTOR 1466995.
Losos, J.B. (2011). Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles. University of California Press. pp. 279–281. ISBN 978-0-520-26984-2.
Claussen, D.L.; Art, G.R. (1981). "Heating and cooling rates in Anolis carolinensis and comparisons with other lizards". Comparative Biochemistry and Physiology Part A: Physiology. 69 (1): 23–29. doi:10.1016/0300-9629(81)90634-4.
Yabuta, S.; Suzuki-Watanabe, A. (2011). "Function of Body Coloration in Green Anoles (Anolis carolinensis) at the Beginning of the Breeding Season: Advertisement Signaling and Thermoregulation". Current Herpetology. 30 (2): 155–158. doi:10.5358/hsj.30.155.
"False Cape State Park". Retrieved 2020-05-20.
Gary Nafis (2013). "Non-Native Reptiles and Amphibians Established In California". CaliforniaHerps.com. Retrieved 2013-02-01.
Daniel F. Culbert; County Extension Agent (2002). "LEAPIN' LIZARDS". University of Florida IFAS extension. Retrieved 2014-05-09.
Sezen, Uzay. "Territorial aggression between two green anole males". Retrieved 16 July 2011.
Irschick, Duncan J.; Gentry, Grant; Herrel, Anthony; Vanhooydonck, Bieke (2006-03-01). "Effects of Sarcophagid Fly Infestations on Green Anole Lizards (Anolis carolinensis): An Analysis across Seasons and Age/Sex Classes". Journal of Herpetology. 40 (1): 107–112. doi:10.1670/132-05A.1. ISSN 0022-1511. S2CID 52258994.
Greenberg, Bernard, and Gladwyn Kingsley Noble. "Social behavior of the American chameleon (Anolis carolinensis Voigt)." Physiological Zoology 17.4 (1944): 392-439.
Crews, David. "Hemipenile preference: stimulus control of male mounting behavior in the lizard Anolis carolinensis." Science 199.4325 (1978): 195-196.
"NHGRI's Large-Scale Sequencing Research Network Sets Its Sights on Disease Targets" (Press release). NIH News. 2005-10-17.
Ad hoc Reptilian Genomics Working Group (2005-07-11). "Proposal to Sequence the First Reptilian Genome: the Green Anole Lizard, Anolis carolinensis" (PDF). National Human Genome Research Institute. Retrieved 2010-05-05.
Sezen, Uzay. "Green anole changing color". Retrieved 16 May 2011.
Sweetlove L (31 Aug 2011). "Lizard genome unveiled". Nature. doi:10.1038/news.2011.512.
Alföldi J, Di Palma F, Grabherr M, Williams C, Kong L, et al. (2011). "The genome of the green anole lizard and a comparative analysis with birds and mammals". Nature. 477 (7366): 587–591. Bibcode:2011Natur.477..587A. doi:10.1038/nature10390. PMC 3184186. PMID 21881562.