Anoles are fascinating reptiles known for their ability to change color, adapting to their surroundings or expressing their mood. This chameleon-like trait sparks curiosity, especially regarding unusual “blue” variations. This article explores the common green anole, explains how genetic factors can lead to a blue appearance, and distinguishes this from a distinct species known for its true blue hue.
Understanding the Green Anole
The green anole (Anolis carolinensis) is a small to medium-sized lizard native to the southeastern United States, from Virginia to Florida and west to Texas. Often called the “American chameleon” due to its color-shifting ability, it is not a true chameleon. These lizards measure between 5 to 8 inches in length, including their tail.
Green anoles have a narrow head, a sharp snout, and white lips and belly. Their feet have specialized pads for climbing, reflecting their semi-arboreal nature. They inhabit high-humidity areas like swamps, forests, wooded beaches, residential yards, and parks.
These lizards perch on trees, shrubs, vines, or fences, often basking in the sun. Their diet consists primarily of insects, including spiders, flies, crickets, and small beetles. Males display a prominent pink or red dewlap, a flap of skin under their throat, during social interactions and mating rituals.
The Biology of Blue Green Anoles
Green anoles’ color-changing capabilities stem from specialized skin cells called chromatophores. These cells are arranged in layers and contain different pigments: melanophores (dark melanin), xanthophores (yellow), and iridophores (blue light-reflecting cells). The combination and distribution of these pigments determine the lizard’s visible color. For instance, typical green coloration results from blue light reflected by iridophores passing through the yellow pigments of xanthophores.
When a green anole appears blue or turquoise, it is due to a genetic mutation called axanthism. This mutation interferes with the lizard’s ability to produce yellow pigment, causing xanthophores to be absent or non-functional. Without yellow pigment to combine with the blue light reflected by iridophores, the underlying blue structural color becomes visible.
This blue-phased variation is rare, occurring in approximately one out of every 20,000 hatched green anoles. While striking and prized in the pet trade, this unusual coloration provides less camouflage in the wild, potentially impacting the lizard’s ability to hunt prey and evade predators. These blue individuals are still Anolis carolinensis, exhibiting a rare genetic variation within their species.
The Distinct True Blue Anole
Beyond the rare blue-phased green anole is a distinct species: the blue anole, Anolis gorgonae. This lizard is unique for its entirely blue coloration in both sexes, a rare trait among lizards globally. Unlike the green anole’s color shifts, Anolis gorgonae maintains its vibrant blue hue, though intensity can vary with temperature, mood, and social interactions.
The blue anole is a small, slender, and highly arboreal species, typically measuring 5 to 8 inches in length, including its tail. It is found exclusively on Gorgona Island, a small landmass off the Pacific coast of Colombia. This species primarily inhabits the dense tropical rainforest canopy, often perching on open branches and tree trunks 3 to 15 meters above ground.
Male Anolis gorgonae possess a pure white dewlap, which contrasts with their blue bodies and is used for communication. Estimating the blue anole’s population has been challenging due to its isolated environment and elusive nature. It is currently classified as “Near Threatened” due to its restricted range and vulnerability to introduced predators like the western basilisk lizard, rats, cats, and capuchin monkeys.
Anoles in Their Environment and as Pets
Green anoles play a role in their native ecosystems as insectivores, helping control invertebrate populations. They are also a common prey item for various animals, including snakes, birds, and larger reptiles. In areas like Florida, they face competition from introduced species such as the brown anole (Anolis sagrei), which can impact their ground-level territories.
As pets, green anoles are popular due to their small size and engaging behavior. A single green anole can be housed in a vertical enclosure, with a minimum size of 24x24x24 inches for climbing and natural behaviors. They require specific environmental conditions: daytime temperatures between 77°F and 86°F, cooler night temperatures of 70°F to 75°F, and humidity levels around 60-70%.
Their captive diet should consist of gut-loaded insects like crickets, mealworms, and waxworms, dusted with calcium and vitamin supplements. Juveniles should be fed daily, while adults can be fed every other day. While generally docile, excessive handling can cause stress, so interaction is best kept minimal and often associated with feeding.