56-519: A chameleon is an Old World lizard belonging to the family Chamaeleonidae. Chameleon (or variants such as chamaeleon and cameleon ) may also refer to: Chameleon Chameleons or chamaeleons ( family Chamaeleonidae ) are a distinctive and highly specialized clade of Old World lizards with 200 species described as of June 2015. The members of this family are best known for their distinct range of colours, being capable of colour-shifting camouflage . The large number of species in
112-404: A compound of χαμαί ( khamaí ) "on the ground" and λέων ( léōn ) "lion". In 1986, the family Chamaeleonidae was divided into two subfamilies, Brookesiinae and Chamaeleoninae . Under this classification, Brookesiinae included the genera Brookesia and Rhampholeon , as well as the genera later split off from them ( Palleon and Rieppeleon ), while Chamaeleoninae included
168-410: A crest of small spikes extending along the spine from the proximal part of the tail to the neck; both the extent and size of the spikes vary between species and individuals. These spikes help break up the definitive outline of the chameleon, which aids it when trying to blend into a background. Chameleons have the most distinctive eyes of any reptile. The upper and lower eyelids are joined, with only
224-424: A monophyletic group. While some authorities have previously preferred to use this subfamilial classification on the basis of the absence of evidence principle, these authorities later abandoned this subfamilial division, no longer recognizing any subfamilies with the family Chamaeleonidae. In 2015, however, Glaw reworked the subfamilial division by placing only the genera Brookesia and Palleon within
280-408: A chameleon's skeleton, possibly giving chameleons a secondary signaling system that does not interfere with their colour-changing ability, and may have evolved from sexual selection . Chameleons primarily live in the mainland of sub-Saharan Africa and on the island of Madagascar, although a few species live in northern Africa , southern Europe (Portugal, Spain, Italy, Greece, Cyprus and Malta),
336-414: A lattice of guanine nanocrystals, and by exciting this lattice the spacing between the nanocrystals can be manipulated, which in turn affects which wavelengths of light are reflected and which are absorbed. Exciting the lattice increases the distance between the nanocrystals, and the skin reflects longer wavelengths of light. Thus, in a relaxed state the crystals reflect blue and green, but in an excited state
392-420: A pinhole large enough for the pupil to see through. Each eye can pivot and focus independently, allowing the chameleon to observe two different objects simultaneously. This gives them a full 360-degree arc of vision around their bodies. Prey is located using monocular depth perception , not stereopsis . Chameleons have the highest magnification (per size) of any vertebrate, with the highest density of cones in
448-426: A positive effect on the pineal gland . All chameleons are primarily insectivores that feed by ballistically projecting their long tongues from their mouths to capture prey located some distance away. While the chameleons' tongues are typically thought to be one and a half to two times the length of their bodies (their length excluding the tail), smaller chameleons (both smaller species and smaller individuals of
504-529: A problem, as chameleons have a very effective mechanism of holding onto their prey once the tongue has come into contact with it, including surface phenomena, such as wet adhesion and interlocking, and suction. The thermal insensitivity of tongue projection thus enables chameleons to feed effectively on cold mornings prior to being able to behaviorally elevate their body temperatures through thermoregulation , when other sympatric lizards species are still inactive, likely temporarily expanding their thermal niche as
560-770: A restricted to only one of a few different habitat types. The typical chameleons from the subfamily Chamaeleoninae are arboreal , usually living in trees or bushes, although a few (notably the Namaqua chameleon ) are partially or largely terrestrial . The genus Brookesia , which comprises the majority of the species in the subfamily Brookesiinae, live low in vegetation or on the ground among leaf litter . Many chameleon species have small distributions and are considered threatened. Declining chameleon numbers are mostly due to habitat loss. Most chameleons are oviparous , but all Bradypodion species and many Trioceros species are ovoviviparous (although some biologists prefer to avoid
616-612: A result. Certain species of chameleons have bones that glow when under ultraviolet light , also known as biogenic fluorescence . Some 31 different species of Calumma chameleons, all native to Madagascar , displayed this fluorescence in CT scans . The bones emitted a bright blue glow and could even shine through the chameleon's four layers of skin. The face was found to have a different glow, appearing as dots otherwise known as tubercles on facial bones. The glow results from proteins , pigments , chitin , and other materials that make up
SECTION 10
#1732793644613672-478: A single species in southern Europe, and a few across southern Asia as far east as India and Sri Lanka . They have been introduced to Hawaii and Florida . The English word chameleon ( / k ə ˈ m iː l i ə n / kuh-MEEL-ee-un , / k ə ˈ m i l . j ə n / kuh-MEEL-yuhn ) is a simplified spelling of Latin chamaeleōn , a borrowing of the Greek χαμαιλέων ( khamailéōn ),
728-473: A species specific pattern in their skull tubercles and in Brookesia there is also some in tubercles on the body. The fluorescence is derived from bones that only are covered in very thin skin and it possibly serves a signaling role, especially in shaded habitats. Some species, such as Smith's dwarf chameleon and several others in the genus Bradypodion , adjust their colours for camouflage depending on
784-405: A terrestrial habit have retained the same foot morphology with little modification. On each foot, the five distinguished toes are grouped into two fascicles. The toes in each fascicle are bound into a flattened group of either two or three, giving each foot a tongs -like appearance. On the front feet, the outer, lateral , group contains two toes, whereas the inner, medial , group contains three. On
840-466: Is fully satisfactory, both being used in describing different feet, such as the zygodactyl feet of parrots or didactyl feet of sloths or ostriches, none of which is significantly like chameleon feet. Although "zygodactyl" is reasonably descriptive of chameleon foot anatomy, their foot structure does not resemble that of parrots, to which the term was first applied. As for didactyly, chameleons visibly have five toes on each foot, not two. Some chameleons have
896-402: Is powered by muscle contraction alone, and is heavily thermally sensitive. While other ectothermic animals become sluggish as their body temperatures decline, due to a reduction in the contractile velocity of their muscles, chameleons are able to project their tongues at high performance even at low body temperatures. The thermal sensitivity of tongue retraction in chameleons, however, is not
952-451: Is still unknown, there is one aspect of the evolutionary history of chameleon colour change that has already been conclusively studied: the effects of signal efficacy. Signal efficacy, or how well the signal can be seen against its background, has been shown to correlate directly to the spectral qualities of chameleon displays. Dwarf chameleons, the chameleon of study, occupy a wide variety of habitats from forests to grasslands to shrubbery. It
1008-491: Is the most recently described new species in the subfamily Brookesiinae . A different species, B. nana , is the first chameleon known not to change colors. The generic name Brookesia is in honor of British naturalist Joshua Brookes . Most Brookesia are on CITES Appendix II, the only exception being B. perarmata on Appendix I (a species also listed as endangered and a newly discovered Brookesia nana listed as Critically Endangered by IUCN ). Consequently,
1064-485: Is to regulate their body temperatures, either to a darker colour to absorb light and heat to raise their temperature, or to a lighter colour to reflect light and heat, thereby either stabilizing or lowering their body temperature. Chameleons tend to show brighter colours when displaying aggression to other chameleons, and darker colours when they submit or "give up". Most chameleon genera (exceptions are Chamaeleo , Rhampholeon and Rieppeleon ) have blue fluorescence in
1120-543: The Brookesiinae subfamily, with all other genera being placed in Chamaeleoninae . Some chameleon species are able to change their skin coloration . Different chameleon species are able to vary their colouration and pattern through combinations of pink, blue, red, orange, green, black, brown, light blue, yellow, turquoise, and purple. Chameleon skin has a superficial layer which contains pigments, and under
1176-516: The Middle East , southeast Pakistan , India , Sri Lanka , and several smaller islands in the western Indian Ocean . Introduced , non-native populations are found in Hawaii and Florida. Chameleons are found only in tropical and subtropical regions and inhabit all kinds of lowland and mountain forests, woodlands, shrublands, savannas , and sometimes deserts , but each species tends to be
SECTION 20
#17327936446131232-467: The osmolarity of pieces of white skin. Colour change in chameleons has functions in camouflage , but most commonly in social signaling and in reactions to temperature and other conditions. The relative importance of these functions varies with the circumstances, as well as the species. Colour change signals a chameleon's physiological condition and intentions to other chameleons. Because chameleons are ectothermic , another reason why they change colour
1288-447: The retina . Like snakes , chameleons do not have an outer or a middle ear , so there is neither an ear-opening nor an eardrum. However, chameleons are not deaf: they can detect sound frequencies in the range of 200–600 Hz. Chameleons can see in both visible and ultraviolet light . Chameleons exposed to ultraviolet light show increased social behavior and activity levels, are more inclined to bask, feed, and reproduce as it has
1344-535: The Elder (1st century AD) also discusses chameleons in his Natural History , noting their ability to change colour for camouflage. The chameleon was featured in Conrad Gessner's Historia animalium (1563), copied from De aquatilibus (1553) by Pierre Belon . In Shakespeare's Hamlet , the eponymous Prince says "Excellent, i' faith, of the chameleon's dish. I eat the air, promise-crammed." This refers to
1400-535: The Elizabethan belief that chameleons lived on nothing but the air. Brookesia Brookesia is a genus of chameleons , lizards in the family Chamaeleonidae . The genus is endemic to Madagascar . Member species range from small to very small in size, and are known collectively as leaf chameleons (though this common name is also used for species in the genera Rieppeleon and Rhampholeon ). Brookesia includes species considered to be
1456-829: The Upper Miocene (about 5–13 mya) of Kenya. The chameleons are probably far older than that, perhaps sharing a common ancestor with iguanids and agamids more than 100 mya (agamids being more closely related). Since fossils have been found in Africa, Europe, and Asia, chameleons were certainly once more widespread than they are today. Although nearly half of all chameleon species today live in Madagascar, this offers no basis for speculation that chameleons might originate from there. In fact, it has recently been shown that chameleons most likely originated in mainland Africa. It appears there were two distinct oceanic migrations from
1512-415: The authors indicated that the lizard was a stem -chamaeleonid. However, Matsumoto & Evans (2018) reinterpreted this specimen as an albanerpetontid amphibian. This specimen was given the name Yaksha perettii in 2020, and was noted to have several convergently chameleon-like features, including adaptations for ballistic feeding. While the exact evolutionary history of colour change in chameleons
1568-625: The body outline and remain hidden from a potential enemy's sight. Only if detected, chameleons actively defend themselves. They adopt a defensive body posture, present an attacker with a laterally flattened body to appear larger, warn with an open mouth, and, if needed, utilize feet and jaws to fight back. Vocalization is sometimes incorporated into threat displays. Chameleons are parasitized by nematode worms, including threadworms ( Filarioidea ). Threadworms can be transmitted by biting insects such as ticks and mosquitoes . Other roundworms are transmitted through food contaminated with roundworm eggs;
1624-504: The captive-breeding in the U.S. which has increased to the point that the U.S. can fulfill its demand, and has now even become a major exporter as well. In the U.S. they are so popular, that despite Florida having six invasive chameleon species due to the pet trade, reptile hobbyists in these areas search for chameleons to keep as pets or to breed and sell them, with some selling for up to a thousand dollars. Aristotle (4th century BC) describes chameleons in his History of Animals . Pliny
1680-446: The case of Trioceros jacksonii , or large crests on top of their heads, like Chamaeleo calyptratus . Many species are sexually dimorphic , and males are typically much more ornamented than the female chameleons. Typical sizes of species of chameleon commonly kept in captivity or as pets are: The feet of chameleons are highly adapted to arboreal locomotion , and species such as Chamaeleo namaquensis that have secondarily adopted
1736-435: The chameleon’s brain is constantly analyzing two separate, individual images of its environment. When hunting prey, the eyes focus forward in coordination, affording the animal stereoscopic vision . Chameleons are diurnal and adapted for visual hunting of invertebrates, mostly insects, although the large species also can catch small vertebrates. Chameleons typically are arboreal , but there are also many species that live on
Chameleon (disambiguation) - Misplaced Pages Continue
1792-520: The dynamics of water potential in Chameleon eggs, the consideration of exerted pressure on eggshells will be essential because the pressure of eggshells play an important role in the water relation of eggs during entire incubation period The ovoviviparous species, such as the Jackson's chameleon ( Trioceros jacksonii ) have a five- to seven-month gestation period. Each young chameleon is born within
1848-408: The entoglossal process, over which a tubular muscle, the accelerator muscle, sits. The accelerator muscle contracts around the entoglossal process and is responsible for creating the work to power tongue projection, both directly and through the loading of collagenous elements located between the entoglossal process and the accelerator muscle. The tongue retractor muscle, the hyoglossus, connects
1904-575: The family exhibit considerable variability in their capacity to change colour. For some, it is more of a shift of brightness (shades of brown); for others, a plethora of colour-combinations (reds, yellows, greens, blues) can be seen. Chameleons are also distinguished by their zygodactylous feet, their prehensile tail, their literally compressed bodies, their head casques, their projectile tongues used for catching prey, their swaying gait, and in some species crests or horns on their brow and snout. Chameleons' eyes are independently mobile, and because of this
1960-486: The following examples: Chameleons are preyed upon by a variety of other animals. Birds and snakes are the most important predators of adult chameleons. Invertebrates, especially ants, put a high predation pressure on chameleon eggs and juveniles. Chameleons are unlikely to be able to flee from predators and rely on crypsis as their primary defense. Chameleons can change both their colours and their patterns (to varying extents) to resemble their surroundings or disrupt
2016-651: The forest have a more defined and colourful palette compared to those living in the desert or savanna, which have more of a basic, brown, and charred palette. The oldest described chameleon is Anqingosaurus brevicephalus from the Middle Paleocene (about 58.7–61.7 mya ) of China. Other chameleon fossils include Chamaeleo caroliquarti from the Lower Miocene (about 13–23 mya) of the Czech Republic and Germany, and Chamaeleo intermedius from
2072-411: The genera Bradypodion , Calumma , Chamaeleo , Furcifer and Trioceros , as well as the genera later split off from them ( Archaius , Nadzikambia and Kinyongia ). Since that time, however, the validity of this subfamily designation has been the subject of much debate, although most phylogenetic studies support the notion that the pygmy chameleons of the subfamily Brookesiinae are not
2128-506: The genera Brookesia , Rhampholeon , or Rieppeleon . These are among the most sensitive reptiles one can own, requiring specialized attention and care. The U.S. has been the main importer of chameleons since the early 1980s accounting for 69% of African reptile exports. However, there have been large declines due to tougher regulations to protect species from being taken from the wild and due to many becoming invasive in places like Florida. They have remained popular though which may be due to
2184-421: The ground. The arboreal species use their prehensile tail as an extra anchor point when they are moving or resting in trees or bushes; because of this, their tail is often referred to as a "fifth limb". Depending on species, they range from rainforest to desert conditions and from lowlands to highlands, with the vast majority occurring in Africa (about half of the species are restricted to Madagascar ), but with
2240-428: The hyoid and accelerator muscle, and is responsible for drawing the tongue back into the mouth following tongue projection. Tongue projection occurs at extremely high performance, reaching the prey in as little as 0.07 seconds, having been launched at accelerations exceeding 41 g . The power with which the tongue is launched, known to exceed 3000 W kg , exceeds that which muscle is able to produce, indicating
2296-550: The larvae burrow through the wall of the intestine into the bloodstream. Chameleons are subject to several protozoan parasites, such as Plasmodium , which causes malaria , Trypanosoma , which causes sleeping sickness , and Leishmania , which causes leishmaniasis . Chameleons are subject to parasitism by coccidia , including species of the genera Choleoeimeria , Eimeria , and Isospora . Chameleons are popular reptile pets, mostly imported from African countries like Madagascar, Tanzania, and Togo. The most common in
Chameleon (disambiguation) - Misplaced Pages Continue
2352-404: The layer are cells with very small (nanoscale) guanine crystals. Chameleons change colour by "actively tuning the photonic response of a lattice of small guanine nanocrystals in the s-iridophores". This tuning, by an unknown molecular mechanism, changes the wavelength of light reflected off the crystals which changes the colour of the skin. The colour change was duplicated ex vivo by modifying
2408-420: The lizard has "short and wide skull, large orbits, elongated and robust lingual process, frontal with parallel margins, incipient prefrontal boss, reduced vomers, absent retroarticular process, low presacral vertebral count (between 15 and 17) and extremely short, curled tail"; the authors considered these traits to be indicative of the lizard's affiliation with Chamaeleonidae. The phylogenetic analysis conducted by
2464-408: The longer wavelengths such as yellow, orange, green, and red are reflected. The skin of a chameleon also contains some yellow pigments, which combined with the blue reflected by a relaxed crystal lattice results in the characteristic green colour which is common of many chameleons in their relaxed state. Chameleon colour palettes have evolved through evolution and the environment. Chameleons living in
2520-603: The mainland to Madagascar. The diverse speciation of chameleons has been theorized to have directly reflected the increase in open habitats (savannah, grassland, and heathland) that accompanied the Oligocene period. Monophyly of the family is supported by several studies. Daza et al. (2016) described a small (10.6 mm in snout-vent length), probably neonatal lizard preserved in the Cretaceous ( Albian - Cenomanian boundary) amber from Myanmar . The authors noted that
2576-411: The presence of an elastic power amplifier to power tongue projection. The recoil of elastic elements in the tongue apparatus is thus responsible for large percentages of the overall tongue projection performance. One consequence of the incorporation of an elastic recoil mechanism to the tongue projection mechanism is relative thermal insensitivity of tongue projection relative to tongue retraction, which
2632-406: The rear feet, this arrangement is reversed, the medial group containing two toes, and the lateral group three. These specialized feet allow chameleons to grip tightly onto narrow or rough branches. Furthermore, each toe is equipped with a sharp claw to afford a grip on surfaces such as bark when climbing. It is common to refer to the feet of chameleons as didactyl or zygodactyl , though neither term
2688-544: The same species) have recently been found to have proportionately larger tongue apparatuses than their larger counterparts. Thus, smaller chameleons are able to project their tongues greater distances than the larger chameleons that are the subject of most studies and tongue length estimates, and can project their tongues more than twice their body length. The tongue apparatus consists of highly modified hyoid bones , tongue muscles , and collagenous elements . The hyoid bone has an elongated, parallel-sided projection, called
2744-483: The same species. Eggs generally hatch after four to 12 months, again depending on the species. The eggs of Parson's chameleon ( Calumma parsoni ) typically take 400 to 660 days to hatch. Chameleons lay flexible-shelled eggs which are affected by environmental characteristics during incubation. The egg mass is the most important in differentiating survivors of Chameleon during incubation. An increase in egg mass will depend on temperature and water potential. To understand
2800-440: The signals are only shown briefly; chameleons are almost always muted cryptic colours. Chameleons vary greatly in size and body structure, with maximum total lengths varying from 22 mm (0.87 in) in male Brookesia nana (one of the world's smallest reptiles ) to 68.5 cm (27.0 in) in the male Furcifer oustaleti . Many have head or facial ornamentation, such as nasal protrusions, or horn-like projections in
2856-467: The sticky transparent membrane of its yolk sac. The mother presses each egg onto a branch, where it sticks. The membrane bursts and the newly hatched chameleon frees itself and climbs away to hunt for itself and hide from predators. The female can have up to 30 live young from one gestation. Chameleons generally eat insects , but larger species, such as the common chameleon, may also take other lizards and young birds . The range of diets can be seen from
SECTION 50
#17327936446132912-603: The term ovoviviparous because of inconsistencies with its use in some animal groups, instead just using viviparous ). The oviparous species lay eggs three to six weeks after copulation . The female will dig a hole—from 10–30 cm (4–12 in), deep depending on the species—and deposit her eggs. Clutch sizes vary greatly with species. Small Brookesia species may only lay two to four eggs, while large veiled chameleons ( Chamaeleo calyptratus ) have been known to lay clutches of 20–200 (veiled chameleons) and 10–40 (panther chameleons) eggs. Clutch sizes can also vary greatly among
2968-613: The trade are the Senegal chameleon ( Chamaeleo senegalensis ), the Yemen or veiled chameleon ( Chamaeleo calyptratus ), the panther chameleon ( Furcifer pardalis ), and Jackson's chameleon ( Trioceros jacksonii ). Other chameleons seen in captivity (albeit on an irregular basis) include such species as the carpet chameleon ( Furcifer lateralis ), Meller’s chameleon ( Trioceros melleri ), Parson’s chameleon ( Calumma parsonii ), and several species of pygmy and leaf-tailed chameleons, mostly of
3024-596: The vision of the specific predator species (for example, bird or snake) by which they are being threatened. In the introduced Hawaiian population of Jackson's chameleon , conspicuous colour changes that are used for communication between chameleons have increased whereas anti-predator camouflage colour changes have decreased relative to the native source population in Kenya where there are more predators. Chameleons have two superimposed layers within their skin that control their colour and thermoregulation. The top layer contains
3080-778: The world's smallest chameleons, and are also among the smallest reptiles . Members of the genus Brookesia are largely brown, and most are essentially terrestrial . A significant percentage of the species in the genus were only identified to science within the last three decades, and a number of species that still have not received a scientific name are known to exist. Most inhabit very small ranges in areas that are difficult to access, and due to their small size and secretive nature, they have been relatively poorly studied compared to their larger relatives. Brookesia are abundant in low-disturbance riparian zones and low-disturbance rainforests. Brookesia are scarce in high-disturbance forests recovering from burning. As of 2024, Brookesia nofy
3136-449: Was demonstrated that chameleons in brighter areas tended to present brighter signals, but chameleons in darker areas tended to present relatively more contrasting signals to their backgrounds. This finding suggests that signal efficacy (and thus habitat) has affected the evolution of chameleon signaling. Stuart-Fox et al. note that it makes sense that selection for crypsis is not seen to be as important as selection for signal efficacy, because
#612387