Veiled chameleon

The veiled chameleon (Chamaeleo calyptratus) is a species of chameleon (family Chamaeleonidae) native to the Arabian Peninsula in Yemen and Saudi Arabia. Other common names include cone-head chameleon and Yemen chameleon.
==Description==
The male is long from the snout to the tip of the tail. The female is shorter, no more than about , but it has a thicker body. Both sexes have a casque on the head which grows larger as the chameleon matures, reaching about in the largest adults. Newly hatched young are pastel green in color and develop stripes as they grow. Adult females are green with white, orange, yellow, or tan mottling. Adult males are brighter with more defined bands of yellow or blue and some mottling.Veiled Chameleon. Smithsonian National Zoological Park.
Coloration can be affected by several factors, including social status. In experimental conditions, young veiled chameleons reared in isolation are darker and duller in color than those raised with other individuals. Females change color across their reproductive cycles. Chameleons also tend to change to a much darker color when stressed.
===Subspecies===
*Chamaeleo calyptratus calyptratus A.M.C. Duméril & A.H.A. Duméril, 1851 – veiled chameleon
*Chamaeleo calyptratus calcarifer W. Peters, 1871 – short-casqued chameleon
==Habitat and Distribution==
The veiled chameleon (Chamaeleo calyptratus) is an arboreal species. It is native to the south-western Arabian Peninsula where the climate is semi-arid and tropical. It is highly susceptible to stress which makes it a species difficult to treat in captivity.
This chameleon lives in a number of habitat types in its native range, including plateaus, mountains, and valleys. Like most other chameleons, it is arboreal, living in trees and other large plants. It prefers warmer temperature, generally between .
==Diet==
The veiled chameleon is primarily insectivorous. It is one of several chameleon species also known to consume plant matter, perhaps as a source of water during the dry season.
==Reproduction and Life Cycle==
The lifespan is about 5 years for females, and up to 8 years for males. They reach sexual maturity at four to five months. They breed more than once a year. The female lays large clutches of up to 85 eggs and buries them in sand. The eggs are white with a tough skin. The embryos experience a diapause, a length of time when they are dormant in the egg before they begin developing. Increasing temperatures in the substrate initiate development.
A 2004 study found that the embryonic development of chameleons (specifically the veiled chameleon) is usually initiated at fertilization and continues until hatching, but sometimes development is arrested at the gastrula stage for months after the eggs have been laid. The researchers involved discovered that moisture levels have little to do with this delay, but that temperature plays a determinant role in development time. An increase in ambient temperature initiates development of diapuasing embryos.
Juvenile chameleons can grow up to two orders of magnitude in body mass within a year of hatching. The feeding mechanisms (mouth, snout, tongue, jaw), all grow rapidly while still needing to be functional. Thus, the musculoskeletal system of the feeding mechanisms grow with negative allometry relative to snout-vent length (SVL). Studies on captured veiled chameleons showed that velocity of jaw movement tends to be greater in adults than juveniles. Thus in the development phase between adult and juvenile, there is a change in energy storage and tongue projection release mechanisms.
It was found that unlike many other reptiles, the sex ratios of the veiled chameleon are not affected by incubation temperature. Even with differential mortality as a factor, the sex ratio bias is negligible. Anecdotal suggestions of temperature-dependent sex ratios in the veiled chameleon were accrued from reporting and statistical errors.
==Disease==
The veiled chameleon, like many reptiles, is susceptible to ocular infections. Similar subcutaneous swellings can be associated with bacterial or fungal abscesses, parasitic infestation, and (rarely) neoplasia.
Juvenile veiled chameleons in captivity often develop nutritional metabolic bone disease but will not develop it if fed dietary supplements of Ca, vitamin A, vitamin D, and cholecalciferol as well as exposure to UVB radiation.
Veiled chameleons in captivity tend to develop maladies such as hypovitaminosis A, hypervitaminosis A, renal failure, dystocia (a failure to lay eggs), respiratory problems (usually due to improper humidity), parasitic infections, and oral cavity problems Corneal damage can also be caused from an overabundance of UVB radiation.
==Protective Coloration and Behavior==
For color changing species such as the veiled chameleon, signaling is important between animals to prevent needless energy expended on attacking competition. Stable and nonaggressive states come with a static coloration and will have a dynamic change when that state is altered. Veiled chameleons will typically brighten their coloring before approaching a rival as a signal of aggression. They will also maximize their stripe brightness for as long as possible to signal the strength of their bite. The longer and brighter the stripe lasts correlates to a stronger bite. This may aid in deterring disproportionately weaker or stronger chameleons from challenging. In this way, both contestants will save time, risk, and energy by not challenging an asymmetrical rival. It is likely that such color changing behavior serves as an evolutionary stable strategy to mutually benefit individuals by preventing unnecessary escalation. Brighter and more yellow stripes are also a signal of increased aggression.
While brighter strip coloring typically correlates to more willingness to approach an opponent, brighter head coloring signified a higher tendency to win fights. Rapidity of color change was also telling of the success of a confrontational outcome. Veiled chameleons are one of the first species to undergo color changing studies focused on speed rather than just intensity of the color. Male veiled chameleons tend to engage in vehement intrasexual aggressive behavior. Before engaging, males will typically engage the color change laterally from a distance to maximize the opportunity to assess the coloration. When males engage with one another, they tend to begin the confrontation head to head which offers a clear view of the vivid head color change.
All chameleons can engage in color change through a lattice of guanine nanocrystals embedded in a superficially thick layer of dermal iridophores. Veiled chameleons specifically exhibit two superposed layers of iridophores. The two layer structure may allow veiled chameleons to camouflage as well as rela beahvioral signalling and may also provide thermal protection.
==Mating==
Males display for females during courtship, performing behaviors such as "head rolls" and "chin rubs". Females change color when they are receptive to breeding, and males are more likely to court them during this time.
Females are receptive to mating when pale-blue (robin’s egg shade) spots appear on their dorsum. They undergo constant clutch cycles that correlate with their hormonal reproductive status. 
Male courtship involves exhibiting bright colors, lateral body flattening, body swaying, and tail curling. Males will approach the females and nudge them with their chin while vibrating from an internal origin during contact. The female will then mount the male and the male uses tarsal spurs to caress the female’s flank. Copulation can last anywhere between a few minutes to an hour and can occur several times per day. When copulation is successful, females will darken their green coloration and the intensity of their yellow patterns will increase. If a female is not receptive to the male, her body will turn dark brown to black with white or yellow mottled markings. She may also become aggressive or violent and bite the male if he continues to advance unwanted.
==Parental Care==
After mating in captivity, a female chameleon will decrease feeding three to four weeks and will spend more time at the bottom of the cage searching for an appropriate egg-laying site. Tunnels will typically reach to the bottom of the container and will be covered with substrate debris after oviposition is completed (which tends to make them difficult to find). Females may dig another tunnel and lay more eggs after about a week. Females should be given easy access between higher sites in the cage and their tunnels via a branch or something similar.
In captivity, eggs should be retrieved then placed into tupperware with a 1:1 ratio mix of vermiculite and water to a depth of about 1-1.5 inches with the eggs buried lengthwise and half covered. Eggs may absorb moisture and expand so they should be placed 0.5 to 1 inches apart from each other. Eggs should be incubated at 26 to 30 degrees Celsius at a humidity of 95%. Neonates should be allowed at least one day to roam their container before moving. Neonate nurseries should consist of a ten gallon screen top aquarium with a base one third to one half filled with decorative artificial plants. Two to six hatchlings should be raised together for the first few months then moved to adult enclosures with increased amounts of vegetation once they reach four to six inches. They can be placed individually from each other once they reach four to six months old.
==In Captivity==
The veiled chameleon is the most common Chamaeleo species in the pet trade. It is easy to breed and prolific in its egg production. It tolerates a range of conditions and survives well in captivity.
Incubation temperature affects egg survival, incubation, and body mass of the juvenile, but does not affect selected body temperature or sprint speed. Moderate environmental temperatures are preferred, but temperatures above the optimal range lead to high mortality and slow development rate.
Locusts are a nutritional diet for captive veiled chameleons.
==Recommended Care==
Veiled chameleons have been bred in captivity for almost thirty years. Recommended care instructions include rooms kept at 21 to 24 degrees Celsius at 50% humidity. For every cage that has a female, a five-gallon bucket, a plastic nursery potted plant, or a fourteen gallon plastic tub with eight inches of tunnel material (an ideal mixture entails peat moss, sand, and top soil) should be placed in the cage and left alone at all times as any females reach sexual maturity (which should be around six months of age). 
If multiple cages must be placed alongside each other, it is best to place a sheet between them to reduce visibility and territorial stress. It is ideal to place a weeping fig or similar artificial plant in each adult cage and a reflector about 4 to 8 inches above the highest basking perch. All cages should have a 60-100 Watt blue daylight incandescent bulb and a fluorescent hood fixture set to a 12 to 12 hour per day and night cycle. A large multiple-chameleon colony is best constructed with three to four month old juveniles. Three males and six females should be placed together. For smaller groups, two juveniles should always be placed together. Adults can be solitary. 
Large colonies (including up to eight individuals) must be set up with an automated watering system. In this case, pipes should be placed across the top of the cage and the spray nozzles positioned over leaves and broad flat surfaces so the chameleons can drink from the collected droplets. Chameleons do not drink from bowls but flare their lips when drinking to intake water flow from lateral portions of their snouts. The sprayer should be set to rain at a minimum of two to three times a day for one to three minutes. For smaller colonies (any amount less than eight individuals) the spraying can be done manually two to three times a day for a minute per cage during the morning, afternoon, and night.
On a daily basis, spot-cleaning should be done as necessary to remove fecal matter, dead food matter (crickets or locusts), leaves, and debris. Once every one to two weeks, the plastic base of the cage should be washed with soap and water and disinfected using a 1:10 ratio bleach solution. In the meantime, the chameleon should be placed in a separate tub with grappling material like crumpled paper. Once every two to three weeks, all decorative items and artificial plants should be washed down with soap and water. Chameleons should be fed crickets or other similar bugs (such as locusts) and plants dusted with necessary dietary supplements. Juveniles should be fed daily and adults every second to third day.
==Research==
Because chameleons possess anatomy that is functionalized for an arboreal habitat (such as split hands and feet for grasping, a prehensile tail, a projectile tongue, independently moving turreted eyes, and laterally compressed bodies), the veiled chameleon is becoming an up-and-coming model for the study of functional morphology and evolutionary developmental biology (ev-devo). A 2019 study assembled an annotated, multi-tissue transcriptome for the veiled chameleon to use as a resource in evolutionary and developmental research. 
The veiled chameleon is currently used as an experimental model to study the evolutionary transition from reptilian amniotes to mammalian and avian species. 
Squamate reptiles comprise about a third of all living amniotes (animals who lay terrestrial eggs). Most of these species are in late development stages at the time of oviposition. However, veiled chameleons are the exception. They breed readily, do not require a cooling period to induce a reproductive cycle, and females produce about 45-90 eggs multiple times a year. Thus, few animals are required to form a productive breeding colony. This makes them an excellent model organism to study developmental and evolutionary phenomena. 
Young chameleons have a heterdont dentition with multicuspid teeth in the caudal jaw area and simple monocuspid teeth rostrally. Chameleon teeth are also acrodontly ankylosed to the bones of the jaw. Odontoblasts produce a layer of predentine that connects the dentine to the supporting bone with both tooth and bone protruding out of the oral cavity and acting as a functional unit. This makes chameleons useful in providing information to study the molecular interaction at the tooth-bone interface in physiological and pathological conditions.
==Invasive species==
This chameleon is an introduced species in Hawaii, where it is invasive in the local ecosystem. There is a breeding population established on Maui. It can also be found in the wild in Florida, where escaped pets have established populations.
==Culture==
The veiled chameleon is the logo of the SUSE Linux operating system.Linux Questions: What kind of lizard is the SUSE mascot Thursday, 14 November 2019
The earliest known description of a chameleon was written by Aristotle.
==Gallery==
Image:C Calyptratus female.jpg
File:Jemenchamäleon Chamaeleo calyptratus.jpg
File:Yemen Chameleon.jpg
File:Chamaeleo calyptratus - AMNH - DSC06272.JPG
File:Jemenchamaeleo maennchen.jpg
==References==
==Further reading==
* 
==External links==
* Veiled Chameleon Care Sheet. The Lizard Lounge.
* Veiled Chameleon. Biotropics.com
Category:Chamaeleo
Category:Lizards of Asia
Chameleon, Veiled
Category:Reptiles described in 1851
Category:Taxa named by André Marie Constant Duméril
Category:Taxa named by Gabriel Bibron