Anolis carolinensis

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Green anole caught outside of our dorm building.

Anolis carolinensis- Carolina anole

Habitat The green anole lives in terrestrial habitats and is generally arboreal (living in trees) but can be found almost anywhere including suburban and urban areas. In a natural habitat, they are found most often on shaded tree branches or in bushes and shrubs with the most prey items avaiable. They also frequently inhabit tall grasses. They often crawl on roofs, houses, fences and decks within urban and suburban areas. They are a common coastal lizard and can also live in tropical and temperate regions.

Range The green anole is native to neotropical and nearctic regions. They are found throughout much of the southeastern United States, extending north through North Carolina, west through Texas, and south through Florida. In some parts of its range it is considered an introduced species. They are now abundant in Hawaii, the Ogasawara Islands of Japan, Cuba and the Bahamas because of this introduction. They were once abundant in Guam after being introduced, but since the brown tree snakes were introduced the green anole number dropped significantly.

Description These lizards range in length from 5 - 8 inches (12 - 20 cm). Their tails are very long and account for more than half of their total body length. The adults weigh between 2 and 6 grams. Females are smaller in all body size measurements at birth. They may be either green or brown or a combination of the colors depending on temperature, excitation and competition. The color variation results from layers of pigmented cells called chromatophores. When brown, they may have faint markings on the back. Brown or black color also indicates cold or stressed conditions. Two different size classes or morphs may be present in adult males of a population. These classes are heavyweights and lightweights. The classes differ by bite force, body mass, length, competition and vertical jump. The heavyweight morph is more dominant. One physical difference between males and females is that males have a pinkish throat fan (dewlap) that is displayed in territorial rivalries or when approaching a potential mate. These lizards are very territorial and males compete heavily for their own mates and home ranges. The green anole is most easily distinguished from the similar brown anole (Anolis sagrei) by green or lightly patterned brown coloration, pinkish throat fan, and by range.

Ecological Notes Anoles are active by day in warm weather and often bask in vegetation, occasionally charging away from a basking spot to grab an insect or chase off a rival anole. During cool weather anoles are often found hiding under tree bark, shingles, or in rotten logs. Sometimes many anoles can be found taking refuge in one spot. They will mate only within their own territories. Males use courtship to attract the attention of females by bobbing their heads up and down and extending their dewlaps. Anoles eat a wide variety of insects, spiders, some arthropods and other invertebrates. At times they will also eat mollusks, grain and seeds.

Personal Information We first noticed the green anole in a small bush outside of the dorms. They were very quick, but after a few failed attempts, we finally caught one! We saw them at a number of places after that including the CSI dock area where our boat and kayaks came into shore and on the deck near the Cape Hatteras lighthouse gift shop. We also experienced a more dominant, aggressive anole at the Cape Hatteras lighthouse that struck one of us trying to capture him. I think he may have been a heavyweight member of the population.

References

Savannah River Ecology Lab UM Zoology

Additional Information

This paper looks into the social dominance hierarchies of male anoles when placed in a habitat with limited resources. Some of the relationships explored in this study are aggressive interactions, social dominance, reproductive activity and perch sites. They found that the losers of fights selected lower perch sites and had depressed rates of courtship as well as less circulating androgen.

Greenberg, N., and Crews, D. 1990. Endocrine and Behavioral Responses to Aggression and Social Dominance in the Green Anole Lizard, Anolis carolinensis. General and Comparative Endocrinology, 77: 246-255.

This study investigated the motoneurons controlling the dewlap extension, which is a sexual behavior of male anoles. No significant differences were found in motoneuron number from breeding season to non breeding season.

O’Bryant, E., Wade, J. 1999. Sexual Dimorphisms in a Neuromuscular System Regulating Courtship in the Green Anole Lizard: Effects of Season and Androgen Treatment. Department of Psychology, and Program in Neuroscience, Michigan State University. 202-213. https://www.msu.edu/~wadej/manuscripts/O%27Bryant1999.pdf

Contributed by Alison Biro - 2014

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