(female all green) showing the long tail and climbing ability typical of anoles Anoles vary in size. Males generally reach a larger size than females, but in a few species it is the other way around. and between in total length, including the tail. There are several large species that are more than in snout-to-vent length. Males of the largest, the
knight anole, There are both robust and gracile species, and the head shape varies from relatively broad to elongate. The tail of anoles varies, but mostly it is longer than the snout-to-vent length. Depending on exact species it can range from slightly shorter to about three times the snout-to-vent. The Caribbean twig ecomorph anoles,
proboscis anole and "
Phenacosaurus" anoles have a
prehensile tail. Semi-aquatic anoles tend to have relatively tall, vertically flattened tails that aid in swimming, and their skin has certain microstructures that make it
hydrophobic, resulting in a thin film of air on the skin surface when submerged and preventing water from staying on when exiting the water. Underneath an anole's toes are pads that have several to a dozen flaps of skin (adhesive
lamellae) going horizontally and covered in microscopic hairlike protrusions (
setae) that allow them to cling to many different surfaces, similar to but not quite as efficient as a
gecko. The extent of these structures and clinging ability varies, being more developed in anole species that live high in the tree
canopy than ones living at lower levels. In one extreme are anoles that easily can run up windows. In the opposite end of the spectrum is the
bulky anole of arid coastal Venezuela and adjacent Colombia, which is the only species completely lacking the specialized toe pad structures. The relative length of the limbs vary, mainly between different species, but to some extent also between different populations of a single species. This depends on things like the preferred perch size and whether there are ground-living predators in a habitat. Despite having relatively small eyes, their primary sense is sight, which is excellent and in color. Their
pupils are round or nearly round. The
Guantanamo anole and
Cuban cave anole have a transparent "window" in their lower eyelid, allowing them to see even with closed eyes, but why they have this adaption is unclear. Anoles have a good
directional hearing, which is able to detect frequencies between 1000 and 7000
Hz and relatively low intensity sounds like the click of a camera. Anoles are
diurnal—active during the daytime—but can also be active during bright moonlit nights and may forage near artificial lights. Many species frequently bask in the sun to increase their temperature, but others are shade-living and do not. The majority can change their color depending on things like emotions (for example, aggression or stress), activity level, levels of light and as a social signal (for example, displaying
dominance), but evidence showing that they do it in response to the color of the background (
camouflage) is lacking. Whether they do it in response to temperature (
thermoregulation) is less clear, with studies supporting it and contradicting it. The extent and variations of this color changing ability differ widely throughout the individual species. For example, the Carolina (or green) anole can change its color from a bright, leafy green to a dull brown color, while the brown anole can only change its shade, ranging from pale gray-brown to very dark brown. The colors are the result of their skin pigment cells, the
chromatophores, of which they have three main types, but the change occurs only in the
melanophores. When triggered by
melanophore-stimulating hormone and other hormones, the
melanosomes of the melanophores partially cover the other skin pigment cells, giving the anole a darker or browner color. and certain anoles that generally are green during the day changing to brown when sleeping at night. Disregarding color change, minor individual variations in the basic color and pattern, mostly related to sex or age, are common. In some anole species this variation is more pronounced and not only related to sex and age. An example of this is the basic color of the
Cayman blue-throated anole, which varies geographically, roughly matching the main habitat at a location. In others it occurs at the same location. This includes the extensive individual variations in the
Guadeloupean anole, which however also shows some geographic variations, but possibly not consistent enough (due in part to
clines) to make the typically recognized
subspecies valid. In the
Puerto Rican giant anole, a species only able to perform minor color changes (essentially lightness/darkness), juveniles are gray-brown and adults typically green, but an uncommon
morph maintains a gray-brown color into adulthood.
Dewlap Most—but not all—anole species have
dewlaps, made of erectile
cartilage (modified from the
hyoid) and covered in skin, that extend from their throat areas. When not in use and closed it lies inconspicuously along the throat and chest. The size, shape, color and pattern of the dewlap vary extensively depending on species, and often it differs between the sexes, being smaller (in some absent) or less colorful in females. In a few species, including the Carolina,
bark,
Cochran's gianthead and
slender anoles, it varies geographically in color depending on subspecies or
morph. Very locally, distinct morphs of a single species that differ in dewlap colors (not just differences between sexes) may occur together. In some species even juveniles have a
dewlap. The
West Cuban and
Cuban stream anoles are the only where both sexes lack a dewlap, but it is reduced and diminutive in about a dozen other species. The dewlap serves as a signal for attracting partners,
territoriality, deterring predators and communicating condition. When several anoles live together the species almost always differ in their dewlap, indicating that it plays a role in
species recognition. Another example is the
red-fanned stout and
large-headed anoles, which are
sister species that overlap in range and are very similar except for their dewlap color. They are highly aggressive to individuals of their own species, but not the other. When one species has its dewlap color modified to resemble the other, only a relatively minor or no increase in aggression occurs, indicating that they still can separate each other. Several other
Iguania genera,
Draco,
Otocryptis,
Polychrus,
Sarada and
Sitana, have evolved relatively large, movable dewlaps independently of the anoles.
Sexual dimorphism (male with proboscis) In some anoles the sexes are very similar and difficult to separate under normal viewing conditions, but most species exhibit clear
sexual dimorphism, which allows one to fairly easily discern between adult males and females. In a few species the female is slightly larger than the male, but in others the sexes are about the same size. However, in most the males are larger, in some more than three times the mass of females. Males of some species have proportionally far longer heads than females, but in others it is nearly alike. The crest along the nape, back and/or tail is larger in the males. In species with tall crests this difference can be obvious, but in small-crested species it is often inconspicuous and easily overlooked, especially when not raised. The dewlap is often larger in males; in some species only the male has a dewlap. A less obvious difference between anole sexes is the enlarged post-cloacal scales in males.
Territoriality and breeding exhibiting push-up behavior s fighting over territory at the top of a fence post Almost all anole species are highly territorial, at least the males, but a few exceptions do exist, including the rock-living
Agassiz's and
Taylor's anoles where males do not defend a territory, and the
grass anole where dominant males accept subordinant non-territorial males within their territory. Territorial anoles will fan their dewlap, bob their head, perform "push-ups", raise their crest and do a wide range of other behaviors to scare away potential competitors. If this does not scare off the intruder, a fight proceeds in which the two anoles attempt to bite each other. During fights some species of anoles are known to vocalize. In addition to the behaviors indicating dominance, anoles may move their head up and down in a head-nod display (not to be confused with the head-bob display where entire frontal part of body is moved through "push-ups"), which is a submissive sign. Females maintain a feeding territory. Males maintain a larger breeding territory, which overlaps with the feeding territory of one or several females. Generally being highly solitary animals, anoles will only infrequently congregate, but in colder regions individuals may rest adjacent to each other in groups during the winter. In addition to differences in the appearance of the dewlap, the frequency of the dewlap opening/closing and the frequency and amplitude of the head bobbing differ between species, allowing them to separate each other. Territoriality is typically aimed at other individuals of the same species, but in a few cases it is also directed towards other anoles, as can be seen between the
crested and
Cook's anoles. Unlike most anoles with widely overlapping ranges, these two inhabit very similar niches and directly compete for resources. s. The male has turned dark from the normal green color. The whitish-gray patches are old skin that is in the process of being
shed The breeding period varies. In species or populations living in highly seasonal regions it is generally relatively short, typically during the wet season. It is prolonged, often even year-round, in species or populations living in regions with less distinct seasons. In some species where it is year-round the egg production is however higher during the rainy season than the dry season, Males attract and
court females by performing a range of behaviors, often mirroring those used to scare away competitors, including extending their dewlap and bobbing their heads. fertilizing the egg inside the
oviduct. The female may mate with multiple males, but is also able to store sperm inside her body for fertilization of eggs several months after mating. A female anole produces an egg in each
ovary, meaning that when one is maturing in one of her
follicles the yolk of another is forming in the other. Among these is the unusual Cuban cave anole where as many as 25 eggs may be glued together in a small cavity on the side of a cave wall. Although typically only laying a single egg per time (clutch), females of many anole species can lay an egg every five days to four weeks. Several species will also eat small vertebrates such as mice, small birds (including nestlings), lizards (including other anole species and
Cannibalism of their own) and frogs. The slow-moving Cuban false chameleon anoles ("
Chamaeleolis") are specialized snail-eaters, and a few semi-aquatic species like the Cuban stream anole may catch prey in water such as shrimp and small fish. Many will chase down or sneak up to a potential prey item, while others are
sit-and-wait predators that pounce on prey when it gets close to the anole. Unusually, the Cuban false chameleon anoles have enlarged and blunt,
molar-like teeth in the rear part of their jaw, allowing them to crush the shells of their snail prey. and overall they are best described as
omnivorous. Some fruit-eating species, like the knight anole, may function as
seed dispersers. although some species are less susceptible to water loss than others and are able to live in relatively arid places.
Predator avoidance and deterrence avoids detection by moving slowly and it will often coordinate its movements with the wind A wide range of animals will eat anoles, such as large spiders,
centipedes, predatory
katydids, snakes, large frogs, lizards, birds,
monkeys,
bats and
carnivoran mammals. At least in part of their range, snakes may be the most significant predator of anoles. Some reptile-eating snakes have a specialized venom that has little effect on humans, but it rapidly kills an anole. On some Caribbean Islands anoles make up as much as 40–75% of the diet of
American kestrels. Anoles mainly detect potential enemies by sight, but their hearing range also closely matches the typical vocal range of birds. If hearing a predatory bird, like a kestrel or hawk, they increase their vigilance. When hearing a non-predatory bird little or no change happens. Some anole species will show their fitness by displaying their dewlap when encountering a predator; the greater the endurance of the anole, the greater the display. Conversely, when suddenly forced to share their habitat with an efficient anole predator like the
northern curly-tailed lizard (for example, if it is introduced to a place where formerly not present), the anoles may decrease the amplitude of their head bobbing, making them less conspicuous, and may become slower to emerge from hiding (less willing to take a risk) after having been scared by a predator. Slow-moving anoles, like the twig ecomorphs of the Caribbean and many
Dactyloa species of mainland Central and South America, are generally cryptically colored and often coordinate their movements with the wind, resembling the surrounding vegetation. However, the anoles lack the specialized toe fringes that helps basilisks when doing this. About two dozen anoles, including almost all members of the
latifrons species group, all in the
chamaeleonidae species group and the
La Palma anole, do not have the ability to autotomize the tail. If caught or cornered, anoles will bite in self-defense. This can be relatively effective against some predators. When fighting back and biting, sometimes for as much as 20 minutes,
Puerto Rican crested anoles escape from more than of all attacks by
Puerto Rican racer snakes. Some species of anoles will vocalize (typically growls, chirps or squeals) when caught. ==Evolution==