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, Yemen chameleon, and Yemeni chameleon. They are born pastel green and without their distinctive casques on their head. When newly hatched veiled chameleons are surprised, they may drop to the ground and turn a bright red color due to stress. As they mature, their casque develops along with more vibrant coloring, as well as a dramatic gular fold that will protrude from their throat and chin. They are known for their variable color changes due to a variety of factors, including to show aggression, social status, reproduction, and stress. Female lifespan is around five years while male lifespan is around eight, and they breed a few times a year.
Etymology The term 'veiled chameleon' refers to the species Chamaeleo calyptratus. 'Veiled' describes their distinctive casque on the head, resembling a veil. This term highlights the species' unique feature. The generic term 'chameleon' is derived from the Greek 'χαμαιλέων' ('khamailéōn'), a compound of 'χαμαί' ('khamaí'), meaning 'low to the ground' and 'λέων' ('léōn'), meaning 'lion', emphasizing the specie's nature as akin to a miniature lion, highlighting its dignified and perhaps majestic demeanor, much like a lion in miniature form, staying close to the ground. The species name 'calyptratus' comes from the Greek 'καλύπτρα' (kalýptra), meaning 'veil' or 'cover', referring to the distinctive casque or veil-like structure on their head. This casque not only serves as a significant physical characteristic but also plays a practical role in channeling dew and rainwater towards the mouth for hydration.
Description
The male is 43 to 61 cm (17 to 24 in) long from the snout to the tip of the tail. The female is shorter, no more than about 35 cm (14 in), but it has a thicker body. Both sexes have a casque on the head which grows larger as the chameleon matures, reaching about 5 cm (2.0 in) in the largest adults. Newly hatched offspring are born pastel green in color and develop stripes and different colors as they mature. 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. Coloration can be affected by several factors, including social status. In experimental conditions, young veiled chameleons reared in isolation developed to be darker and duller in color compared to those raised with other individuals. Females change color over the course of 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 24 and 35 °C (75 and 95 °F).
Diet The veiled chameleon is primarily insectivorous. Like other chameleons, the veiled chameleon has the ability to capture large prey but their diets mainly consist of small prey. Green insects seem to be a favorite. However, it is one of several chameleon species also known to consume plants, such as vegetables and fruits. This is believed to perhaps be used as a source of water during the dry season.
Behavior
Reproduction and life cycle Veiled chameleons reach sexual maturity at four to five months and breed multiple times in a year. The female lays large clutches of up to 85 white, tough eggs and buries them in sand. The embryos experience a diapause, a length of time (usually 60-75 days) 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) usually initiates at fertilization and continues until hatching, but sometimes development stunts 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 diapausing 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. Veiled chameleons have a naturally short lifespan, so even with good care, they may only live 6-8 years. Males typically live longer than females.
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