The brown anole (Anolis sagrei), also known commonly as the Cuban brown anole, Bahaman anole, or De la Sagra's anole, is a species of lizard in the family Dactyloidae. The species is native to Cuba, the Bahamas, Little Cayman, Cayman Brac, Jamaica, the Swan Islands, the Yucatán Peninsula, Belize and the Caribbean coast of Guatemala and Honduras. It has been widely introduced elsewhere, via the importation and exportation of plants where the anole would lay eggs in the soil of the pots, and is now found in Florida and other regions of the United States including southern Georgia, Texas, Louisiana, Tennessee, Mississippi, Alabama, Hawaii, North Carolina, and Southern California. It has also been introduced to other Caribbean islands, Mexico, Singapore, and Taiwan.

This species is highly invasive. They are also much more wary of humans than most other Anole species.

In its introduced range, it reaches exceptionally high population densities, is capable of expanding its range very quickly, and both outcompetes and consumes many species of native lizards, like the green anole. has altered the behavior and negatively affected populations of the native Carolina anole (Anolis carolinensis, also known as the green anole), which have since generally been relegated to the treetops.

Etymology

The specific name, sagrei, is in honor of Spanish botanist Ramón de la Sagra.

Description

The brown anole is normally a light brown color with darker brown to black markings on its back, and several tan to light color lines on its sides. Like other anoles, it can change color; individuals can change their general body coloration to shades of brown, black, or gray, and some display yellowish dots when excited. Color shifts can be rapid in response to threats. Its dewlap ranges from yellow to orange-red.

The males can grow as large as their male Carolina anole counterparts, around long, with some individuals topping . The females are also around the size of female Carolina anoles, which ranges from . The male brown anole's head is smaller than that of the male Carolina anole.

Female anolis lizards exhibit heritable polymorphism in their dorsal patterning. A study in Gainesville, Florida reported that one-third of A. sagrei females displayed a male-like chevron dorsal pattern, while other females had a striped dorsal pattern with continuous variation.

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File:Brownanole-dewlapERB.jpg|Male extending dewlap

File:Brown Anole, Florida.jpg|Florida female

File:Closeupanole.jpg|Female

File:Cuban brown anole (Anolis sagrei sagrei) juvenile.JPG|Grand Cayman juvenile

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Removal

In Taiwan, an investigation discovered that distribution of this foreign species was increasing, posing potential competitive crowding out effect towards the native species such as Diploderma swinhonis and Takydromus formosanus in Taiwan. Therefore, the monitoring removal plan was being carried out in 2009. The current removal methods include manual removal, improving the habitat, capturing with traps, biological control, and drug control. The most effective way of capturing Anolis sagrei is to capture with bare hands at night .

Habitat and distribution

thumb|A Brown anole in central Honduras.

The native range of the brown anole extends over much of the Caribbean, including Jamaica, Cuba, the Cayman Islands, and other countries. Currently, they are considered an invasive species in parts of Florida in the United States, including the Florida Keys, Dade County, Broward County, and Palm Beach County as of 1985. Today, their range has extended as far as Georgia and through Texas to parts of Mexico. It is believed that these lizards were unintentionally brought to the area in cargo shipments for the Caribbean, as well as an intentional release of approximately 100 individuals in 1941.

The brown anole tends to live on the ground, avoiding trees and preferring to live in smaller plants and shrubs and is found in both urban and suburban areas. Brown anoles are less arboreal than the green anoles which are frequently found living in trees, on the ground, or in low vegetation.

Although the brown anole was initially found in the Caribbean and then introduced to southern Florida, the species is now moving north. Specifically, the species has been found in southern Georgia as well as coastal Georgia. Researchers expect that this trend will continue in the coming years and that the brown anole will continue to migrate to other locations in the north. Some research suggests that local spider populations depend directly on the population of the brown anole.

Additionally, the brown anole has been shown to be responsible for the transmission of parasites among lizard populations in Hawaiʻi, which are often deadly for these local populations.

The most closely related species to Anolis sagrei is Anolis nelsoni, also called Nelson's anole.

The brown anole has a shorter snout length than the green anole. When the male anole spots other males in his ground territory, he is very likely to put on displays to attempt to intimidate the competitor. The size of a male also correlates with the height of his perch; that is, larger males are more often found on higher perches and smaller males on lower ones.

Habitat migration

Under certain circumstances, brown anoles leave their current territory and migrate to a new one. Males migrate to new territories in response to male-male competition, with smaller males being more likely to migrate.

Reproduction

In a given habitat, female brown anoles reproduce in the warmer parts of the year. Dewlap extension occurs alongside a number of behaviors exhibited by the brown anole, namely during courtship. During observation, females that mated with multiple males did so because dominance over a territory transferred between males, while the female remained in the same territory. There were no observations of female brown anoles seeking out different males or entering a new territory. A female will lay one egg at a time and can lay a new egg each week of the reproductive season. Brown anoles demonstrate phenotypic plasticity in this trait, akin to very rapid evolution.

Dewlap

Nearly all species of anole, including the Anolis sagrei, have a dewlap on their throat. The dewlap can be used as a means of identifying specific species within the Dactyloidae family. This is useful for not only mate selection between male anoles, but also to ensure the female is indeed mating with an individual within their own species. Dewlaps are believed to be involved in mate selection, as well as communication between individual brown anoles. In captivity, the molted skin may stick to the anole if humidity is too low. The unshed layer of skin can build up around the eyes, preventing the lizard from feeding and may lead to starvation. This can be prevented by maintaining high humidity.alt=brownanoletexas|thumb|Brown anole in [[Rockport, Texas|Rockport, Texas]]

Communication

Anoles use visual cues as their primary signaling mode.

References

  • Brown Anole at Zachary Taylor Beach, Key West, video of Brown Anole displaying courtship behaviour