Chameleons (lat. Chamaeleonidae ), or (lat. Chamaeleontidae ) - a family of a suborder of lizards of the squamous order, adapted to an arboreal lifestyle, capable of changing the color of the body.
Edit General characteristics
The body is strongly compressed laterally, with a short neck and usually a long and tenacious tail. The body is covered with horny kernels and tubercles.
Chameleons vary greatly in size and body structure. Length varies from 15 millimeters in males Brookesia micra Note. 1 to 68.5 centimeters in males Furcifer oustaleti.
On the head of many species, horny and skin outgrowths (ridges, tubercles, pointed horns).
Legs are long five-fingered, ending in two opposed groups of fingers. Toes are arranged in groups (2-3 in skin covers). Thus, the foot and hand of each leg are transformed into peculiar mites, which are very convenient to clasp thin branches.
Tail gradually tapering towards the end can spiral twist down and wrap around branches.
The large round eyes of the chameleons are surrounded by a continuous, scaly annular eyelid, in the center of which there is a small hole for the pupil. Eye movements are not interconnected, each can rotate horizontally (180 °) and vertically (90 °).
Due to this, sitting in place, the lizard can look with one eye up or down, while the second is directed back or to the side. This allows, without moving his head, to observe everything that is happening around.
The tongue, which exceeds the length of the torso along with the head in an extended state, is folded on the hyoid bone with folds and is “packed” in the mouth into a muscle cover. The end of the tongue is thickened and able to strain when promptly ejected from the mouth.
Edit body color change
Chameleons are able to quickly change the color (and pattern) of the body depending on lighting, temperature or irritation.
Most chameleons change color from brown to green and back, but some can take almost any color. In just 20 seconds, repainting can occur.
Chameleons are born with special cells that have color or pigment in them. These cells are in layers under the upper shell of the chameleon. They are called chromatophores. The upper layers of the chromatophores have a red or yellow pigment. Lower layers have blue or white pigment. When these pigment cells change, chameleon skin color changes.
Chromatophores change because they receive a message from the brain. The message tells the cells to grow or contract. These actions make the pigments of the cell mix - just like paint. Melanin also helps the chameleons change color. Melanin fibers can spread like a spider web through the layers of cells, and their presence causes the skin to darken.
Many people think that the color of chameleons is in harmony with their surroundings. Scientists do not agree with this. Their studies show that light, temperature, and mood also make chameleons change. Sometimes a color change can make the chameleon more relaxed. Sometimes it helps to communicate with your own kind.
So changing the color for camouflage is not at all the main goal of the chameleon: there are a lot of photos and video materials that show that the chameleons are not at all the same color as the environment.
It is believed that a chameleon is able to reproduce any pattern of the surrounding background, down to the black and white squares of a chessboard. But in fact, the possibilities of the animal in this respect are limited and no new pattern or pattern that is not characteristic of this species can appear in it.
Chameleons spend most of their lives in trees. It is the color of foliage, bark and other woody "environment" that is closest to the natural color of the skin of the chameleons. It can be (depending on the type) green, beige, light brown. The female is not very different in color from the male. To live among the thickets of wood the chameleons help a long tail. In some species, it also spirals. With this device, the chameleon hooks on the branches, which greatly facilitates the life of the reptile.
Animals descend to the ground during breeding or during hibernation. And only 2-3 species lead a land-based lifestyle.
Chameleons can sit still for hours, tracking down prey. If they move, they prefer to do it slowly. Chameleons can swell with irritation due to pulmonary sacs.
Chameleons feed on insects and other small invertebrates. Large species can eat small birds and lizards. Sentinel prey, they spend motionless several hours on a tree. They are motionless only in appearance. In fact, everything around is monitored by eyes that constantly rotate from side to side.
Reproduction takes place calmly, under normal conditions. Most chameleons are oviparous. They lay eggs in the ground or sand. In clutch there are up to 35 eggs. Some ovoviviparous. They have up to 14 cubs. The incubation period lasts 9 months.
A little chameleon is not able to protect himself. In the wild, the baby is saved by moving in space, sitting on his mother’s back.
Chameleons live 7-9 years.
Almost half of the world's chameleon species live on the island of Madagascar with 59 different species that do not exist anywhere outside the island.
There are numerous species of chameleon. They are common from Africa to southern Europe, from southern Asia to Sri Lanka. They were also imported into the United States in places such as Hawaii, California, and Florida.
Edit Content in captivity
Contained chameleons in the terrarium. Their maintenance does not bring much trouble, you just need to properly arrange the habitat of this reptile and then periodically clean it.
For home improvement, branches are needed at different levels, which is easily arranged in vertical terrariums. In addition, deciduous plants without thorns and thorns are needed. Sand is poured at the bottom, which is periodically wetted with water to maintain moisture. You can spray the walls of the terrarium so that the chameleon licks water, and you can also put a dropper.
Maintaining the required temperature is one of the most important factors for the successful content of chameleons. If the optimum temperature is provided, then they will not hibernate, remaining active all year round. The optimum temperature for them is 24-28 ° C. It was also noted that at 18 ° C the animals still feed, but at 15 ° C it is no longer there.
What is the difference between the types of chameleons
The total number of species almost reaches 200. All of them differ from each other in the following parameters, which take into account the classification of species.
- Size body length. It ranges from 3–5 cm to 30–55 cm.
- Coloring body. Despite the fact that they are capable of mimicry, that is, a change in body color, their initial color depends on the type of animal.
- Form body. Some have a smoother upper back and upper head. Others have crest-shaped processes there. On the head can also be located processes or horns.
It is also called spiky or warty. it one of the largest representatives of the genus of chameleons.
Males are able to reach 45 cm in length, while females are noticeably smaller. Males also have a brighter body color. It feeds, like all other representatives, on insects. The birthplace of a crocodile chameleon is Madagascar.
Distributed in Yemen and Saudi Arabia.
it the biggest representative: males reach in length 55 cm. By color, the females have gray-green skin. Whereas in males such a gray-green background is diluted with vertical yellow stripes interspersed with other colors.
Reference! If the Yemeni chameleon becomes dark in color, this is evidence that the animal is stressed or for females means pregnancy.
Is an one of the largest and most attractively colored. Distributed on the island of Madagascar and adjacent small islets.
Body length up to 35 cm. On the head are two flat helmet-shaped processes.
The predominant coloration colors in males are red, blue, orange, green. Against this background, spots and stripes darker in color and shape may be located. For females, the color is a little calmer, but also varied. Primary colors - beige, yellow, orange.
Important! These animals are quite contact. Therefore, they are one of the most common for growing at home.
One of the rarest but long living, which also has an original body color. It can range from blue and green to yellow with red.
It feeds not only on insects, but also on small rodents and small birds.
It also lives in Madagascar. It differs in small dimensions - about 25 cm. But its color is very bright and varied.
It is distinguished by excellent appetite, which forces him to lead a fairly active lifestyle in natural conditions. On the head of males there are two processes of unusual shape.
Common or European Chameleon
It has a body length of 20 cm. It most common. But outwardly little expressive. Color, as a rule, ranges from gray-green to saturated green.
Important! It took root well in captivity and spread beyond its natural range.
Originally from Tanzania. it alpine lizard with a body length of up to 30 cm. A distinctive feature is that he viviparous.
Attention! All of the above types are suitable for keeping a house in specially designed terrariums.
Have a lot in common with brukesia. Their size is so small that they fit in the palm of your hand. They have a nondescript gray-brown appearance.
Adapted to crawl not only through trees, but also lead a land-based lifestyle.
The emergence of new species.
The chameleon family is attractive not only for its mimicry, but also for constant updating. In 2009, 5 new species of these lizards were discovered right away.
Important! The distribution area of new animals of this genus is so small that they are threatened with complete extinction.
1 view of Madagascar - this is Furcifer timoni glawcharacterized by a bright green color.
The other 4 were discovered in Africa, have a sharply limited area of distribution, and therefore remained open until recently. These are representatives such as Bradypodion ngomeense (dwelling in only one relict forest in KwaZulu-Natal), Kinyongia vanheygeni and Kinyongia magomberae.
Origin of view and description
Photo: Yemeni Chameleon
Yemeni chameleons are representatives of chordate reptiles, belong to the squamous order, suborder of lizards, chameleons, genus and species of real chameleons are allocated to the family.
Chameleons are one of the oldest reptiles on earth. Researchers zoologists described the finds, which, in their opinion, are already about one hundred million years old. The oldest remains of a Yemeni chameleon were discovered in Europe. They indicate that these reptiles existed on the earth more than 25 million years ago.
Appearance and features
Photo: Yemeni chameleon female
This subspecies of chameleons is considered the largest and incredibly beautiful. The body length of adults reaches 45-55 centimeters. These reptiles have a pronounced sexual dimorphism. Female individuals are about a third inferior in size.
A distinctive feature of the Yemeni chameleon is a rather large crest, for which it is called the veil, or helmet-bearers. From afar, the crest really resembles a helmet covering the head of a lizard. It reaches a height of up to ten centimeters.
Young individuals have a rich, vibrant green color. Reptiles tend to change color. Adult individuals change color if they experience a feeling of stress, females during pregnancy, or males during mating when the females approach. Green can change to brown, blue, white, dark brown. As they grow older, the color of the lizards changes. Streaks of bright yellow or orange appear on the body of animals.
Interesting fact. Zoologists claim that the color depends on social status. Lizards that have grown alone have a paler shade than individuals that grew in a collective.
The limbs of animals are thin and long, perfectly adapted for crawling on trees and grabbing branches. The tail is quite long, thicker at the base, becoming thin towards the tip. Chameleons often fold it into a ball when they sit motionless on tree branches. The tail is very important, it serves as a support, participates in maintaining and maintaining balance.
Chameleons have an amazing eye structure. They are able to rotate 360 degrees, providing a full view around. Vision is designed in such a way that with the help of the eyes you can accurately determine the distance to the potential victim.
The tongue of the Yemeni chameleons is long and thin. Its length is about 20-23 centimeters. The tongue has a sticky surface that allows you to grab and hold prey. At the tip of the tongue there is a kind of suction cup that attracts insects and prevents them from slipping away.
Where does the Yemeni chameleon live?
Photo: Adult Yemeni Chameleon
This representative of chordate reptiles lives in natural conditions exclusively on the Yemen Peninsula, the island of Madagascar, in Saudi Arabia. Lizards prefer moist forests, low shrubs and thickets of various types of vegetation. However, zoologists argue that the Yemeni chameleon also feel comfortable in dry regions, in mountainous areas.
It can easily be found where vegetation is very scarce, or, conversely, in the tropics or subtropics. This area of the globe is characterized by very diverse climatic conditions. The most numerous populations are located on the plateaus that are located between Yemen and Saudi Arabia. This part of the continent is characterized by desert and lack of diversity of vegetation, however, chameleons choose coastal areas in which they feel as comfortable as possible.
Mammals were later introduced to Florida and the Hawaiian Islands, where they took root well and quickly acclimatized.
Lizards like to spend a lot of time on the branches of trees and shrubs. However, with a wide variety of chooses from the available species, the most popular types of vegetation. These include acacia, succulent and cactus-like plants and shrubs of the euphorbia family. Often lizards settle near human settlements, choosing gardens and park thickets.
What does a Yemeni chameleon eat?
Photo: Yemeni Chameleon Male
The basis of the diet of reptiles is small insects, or other animals. To catch prey, they have to hunt. To do this, reptiles climb onto a secluded branch of shrubs or trees, and freeze for a long time, waiting for the right moment. At the time of waiting, the body of the lizard is completely immobilized, only the eyeballs rotate.
At such a moment, it is extremely difficult, almost impossible to notice in the foliage of a chameleon. When the prey approaches a fairly close distance, he throws out his tongue with a suction cup at the end and captures the prey. If they come across a large prey, they capture it with their whole mouth.
Interesting fact.Yemeni chameleon is the only representative of this species, which, after reaching puberty, almost completely switches to food vegetation.
What is included in the diet of Yemeni chameleons:
- Small lizards
- Small rodents
- Food of plant origin.
Surprisingly, it is Yemeni chameleons that are herbivores. They eat ripe fruit, as well as succulent leaves and young shoots of various vegetation. When kept in artificial conditions, reptiles gladly eat pears, apples, zucchini, peppers, clover leaves, dandelion, and other vegetation.
To make up for the body’s need for fluids, reptiles lick droplets of morning dew from the vegetation. That is why it is very important when keeping the reptile in artificial conditions, it is necessary to irrigate the terrarium and all surfaces with water to provide the lizards with a source of liquid. A prerequisite is the provision of calcium and vitamins necessary for the full functioning of the Yemeni chameleons.
Features of character and lifestyle
Photo: Yemeni Chameleon
Reptiles tend to spend most of the time on shrubs or trees. They descend to the surface of the earth in the event that they want to change their habitat or need to take shelter under intense heat under stones or other shelters. They go hunting in search of food during daylight hours. For these purposes, choose thick, long branches. Choosing a place and position for hunting, he tries as much as possible to get to the stem or trunk at a distance of at least three meters. In the dark and during the daytime rest climb thin branches of trees and shrubs.
Male individuals tend to be aggressive towards other individuals that appear on their territory. The natural instinct motivates them to defend and defend their territory. Yemeni chameleons seek to scare their potential adversary, forcing him to voluntarily leave someone else's territory. Opponents swell, hiss menacingly, fall flat on a hard, flat surface, open their mouths, nod their heads, turn their tails and turn them around.
In the process of confrontation, reptiles slowly wiggle the body from side to side and change color. If such attempts to scare the enemy were unsuccessful, then you have to resort to a fight. In the process of fighting, reptiles inflict serious injuries and injuries to a friend. In rare cases, such collisions can be fatal.
This happens when there is no way for the weaker opponent to retreat. Starting from the age of four months, males can be aggressive towards each other. Female individuals are distinguished by a humble disposition and do not show aggression to their associates.
Social structure and reproduction
Photo: Animal Yemeni Chameleon
The period of puberty in Yemeni chameleons begins after reaching one to two years of age. The period of marriage depends on climatic conditions and in most cases falls on the period from April to September. With the onset of the mating season, each male tries to attract the attention of a female he likes. To do this, he nods his head, slowly swings his whole body, folds and turns his tail. At this period, males tend to change color to bright and saturated.
A female who is ready to create a pair is covered in turquoise on her back. She calls the male, which pleased her, with her open mouth. The one she does not like, she desperately drives away.
Individuals mate for 15-30 minutes several times a day for 3-5 days. Then the couple breaks up, and the male leaves to look for another pair to enter into a marriage. In some cases, the period of the marriage lasts up to 10-15 days.
Pregnancy of females lasts from 30 to 45 days. During this period of time, females on the body appear spots of turquoise or yellow on a dark green or black background. At the end of the gestation period, the female makes a long, tunnel-shaped hole in which she lays several tens of eggs and gently closes the entrance to the mink. The incubation period lasts 150-200 days.
The sex of hatched chameleons depends on the ambient temperature. If the temperature is approximately 28 degrees, then mainly females will hatch from the eggs, and if the temperature reaches 30 degrees, then predominantly males will appear. All babies are born at a time. The length of their body is 5-7 centimeters. The average life expectancy in natural conditions is 4-7 years.
Natural Enemies of Yemeni Chameleons
Photo: Yemeni Chameleon Adult
When living in natural conditions, Yemeni chameleons have quite a few enemies. They become prey more than large, strong and cunning predators.
- Large predatory mammals,
- Larger reptiles, lizards,
- Feathered predators - raven, herons.
The peculiarity of the chameleon is that instead of hiding and taking flight, by nature he is endowed with the ability to try to scare a possible opponent. That is why when approaching a deadly enemy, the lizard swells, hisses, the more it betrays itself.
Zoologists call the enemies of Yemeni chameleons parasitic worms. When these are started in the body of lizards, they multiply quite quickly, which leads to weakening and exhaustion of the body. In some cases, the number of parasites is so large that they literally eat a lizard alive.
It is worth noting that lizards are very sensitive to lack of fluid, vitamin deficiency, lack of calcium. When dehydrated, the eyes of Yemeni chameleons are constantly closed in the daytime.
A significant contribution to reducing the number of reptiles was made by humans. This is due to the development of new territories, the destruction and destruction of their natural habitat. Deforestation and expansion of agricultural land leads to a reduction in the number of representatives of these flora and fauna.
Population and species status
Photo: Yemeni chameleon female
Despite the fact that chameleons, like no one else, know how to disguise themselves and hide, they cannot be guaranteed to be protected from complete disappearance. At the moment, not only the helmet-bearing species of the chameleon is threatened with extinction, but also other subspecies. It is becoming increasingly difficult for them to survive in natural conditions. Numerous diseases, the destruction of eggs and young individuals, human activity, predators - all these are the reasons for the reduction in their population.
Yemeni chameleons are successfully bred at home in a terrarium, subject to the creation of optimal conditions and the required amount of food supply. It is this subspecies of lizards that is most in demand among breeders of exotic animals.
Zoologists say that the majority of individuals that exist today are found in national parks, zoos, and not in natural conditions. Researchers confidently claim that this species has not completely disappeared due to its ability to quickly adapt to new conditions of detention, tolerate acclimatization and eat plant foods. This allows you to breed them almost everywhere.
Guard Yemeni Chameleons
Photo: Yemeni Chameleon Red Book
For protection purposes, Yemeni or helmet-bearing chameleons are listed in the International Red Book as a species that is on the verge of extinction. This subspecies is not the only one threatened with extinction. All species of chameleons, without exception, are listed in the Red Book, and almost two dozen of them also run the risk of completely disappearing in the near future.
To prevent this, lizards are successfully bred in terrariums in national parks. In the region of their habitat in natural conditions, illegal capture and trade in reptiles is officially prohibited. When propagating and keeping in artificial conditions, the reptiles are provided with all the necessary conditions - the level of lighting, temperature, as well as the prevention of vitamin deficiency, rickets, and parasite infection.
Zoologists make a lot of efforts to create optimal conditions, prevention and treatment of reptile diseases. However, if you do not take into account the veil chameleons that are kept in artificial conditions, the proportion of lizards living in natural, natural conditions is negligible.
Chameleons are recognized as one of the most striking, mysterious and unusual creatures on planet Earth. Only they are characterized by such an unusual ability to change color depending on social status, or psychological state. However, these amazing reptiles may soon disappear from the face of the earth due to human influence and other factors.
Chameleon - Chameleon
|Indian chameleon Chamaeleo zeylanicus , at Mangaon, Maharashtra, India|
Chameleons or chamaeleons (family Chamaeleonidae ) are a distinctive and highly specialized treasure from the Old World of lizards with 203 species described in June 2015, these species come in a range of colors, and many species have the ability to change color.
Chameleons are distinguished by their legs, their very extensive, highly modified, rapidly extrudable tongues, their cerebellar gait, and crests or horns on their forehead and muzzle. Most species, larger, in particular, also have a tenacious tail. The eyes of the chameleons are independently mobile, but aimed at the victim’s position, they are focused forward in coordination, providing the animal with stereoscopic vision.
Chameleons are adapted for climbing and visual hunting. They live in warm habitats that range from rainforests to desert conditions, with various species occurring in Africa, Madagascar, Southern Europe and throughout South Asia as far as Sri Lanka. They have also been introduced to Hawaii, California, and Florida, and are often kept as pets.
English word chameleon (/ to ə m i l i ə n / Kuh-Meel-yun ) is a simplified spelling of Latin Chameleon borrowing the Greek χαμαιλέων ( khamailéōn ), And the compound from χαμαί ( khamaí ) “To the ground” and λέων ( Leon )"a lion". A group of chameleons are called the collective noun "camp."
The Chamaeleonidae family was divided into two subfamilies, Brookesiinae and Chamaeleoninae, according to Claire and Boehme in 1986. In accordance with this classification, Brookesiinae included genera brukesia and african dwarf chameleons as well as childbirth later separated from them ( Palleon and Rippeleon ), while Chamaeleoninae included childbirth Bradypodion , Calumma , Chamaeleo , Furcifer and Trioceros as well as childbirth later separated from them ( Archaius , Nadzikambia and Kinyongia ) Since then, however, the validity of this designation subfamily has been the subject of much discussion, although most phylogenetic studies support the idea that the dwarf chameleons of the Brookesiinae subfamily are not a monophyletic group.
While some authorities previously preferred to use this subfamilial classification on the basis of a lack of evidence of principle, these authorities subsequently did not abandon this subfamilial unit, which no longer recognizes any subfamily with the Chamaeleonidae family.
In 2015, however, Gl reworked the subfamilial separation by accommodating only labor brukesia and Palleon in the Brookesiinae subfamily, with all other genera being placed in Chamaeleoninae.
Some types of chameleons are able to change their skin color. Different species of chameleons are able to change their color and pattern through a combination of pink, blue, red, orange, green, black, brown, light blue, yellow, turquoise, and purple. The chameleon skin has a surface layer that contains pigments, and under a layer of cells with guanine crystals. Chameleons change color by changing the space between the guanine crystals, which changes the wavelength of light reflected from crystals that change the color of the skin.
Color changes in chameleons have functions in camouflage, but most often in social signaling and reactions from temperature and other conditions. The relative importance of these functions varies depending on the circumstances as well as the species. A color change signals the physiological state and intentions of other chameleon chameleons. Chameleons tend to show brighter colors when displaying aggression of other chameleons, and darker colors when they serve or “refuse”. Some species, in particular those from Madagascar and some African genera in tropical rainforest habitats, have blue fluorescence in their skulls of tubercles, leading out of bones and, possibly, serve as signaling.
Some species, such as Smith's dwarf chameleon, adjust their colors to mask according to the vision of specific predator species (birds or snakes) by which they are threatened.
The desert-inhabiting desert chameleon also uses color change as an aid to thermoregulation, turning black in cooler mornings more efficiently absorbs heat, and then light gray to reflect light in the middle of the day. It can show both colors at the same time, gently detached to the left of right on the spine.
Color change mechanism
It has long been believed that chameleons change color by dispersing pigment-containing organelles within their skin. However, a study conducted in 2014 on a panther of chameleons showed that pigment movement is only part of the story.
Chameleons have two superimposed layers within their skin that control their color and thermoregulation. The top layer contains a guanine lattice of nanocrystals, and the distance between the nanocrystals capturing this lattice can be manipulated, which in turn affects which light wavelengths are reflected and which are absorbed. The gripping lattice increases the distance between the nanocrystals, and the skin reflects longer wavelengths of light. Thus, in a relaxed state, crystals reflect blue and green, but in an excited state, longer wavelengths, such as yellow, orange, green, and red, are reflected.
The skin of the chameleon also contains some yellow pigments, which in combination with blue, reflected by the relaxed results of the crystal lattice in the characteristic of green color, which is common to many chameleons in their relaxed state.
Oldest described chameleon Anqingosaurus brevicephalus from the Middle Paleocene (about 58.7-61.7 Ma) from China.
Other chameleon fossils include Chamaeleo caroliquarti from the Lower Miocene (about 13-23 Ma) from the Czech Republic and Germany, as well as Chamaeleo Intermedius from the Upper Miocene (about 5-13 Ma) from Kenya.
Chameleons are probably much older than this, possibly sharing a common ancestor with the iguanids and agamide over 100 million years ago (agamide being more closely related). Since fossils were found in Africa, Europe and Asia, chameleons were, of course, once again widespread than they are today.
Although almost half of all species of chameleons today live in Madagascar, this does not give any reason to assume that chameleons can come from there. In fact, it has recently been shown that chameleons most likely originated in continental Africa. It turns out there are two different oceanic migrations from the mainland to Madagascar.The varied speciation of chameleons was theorized to have directly reflected an increase in open habitats (Savannah, grassland and wasteland) that accompanied the Oligocene period. Monophilia family is supported in several studies.
Daza and other (2016) described a small (10.6 mm long ventilating muzzle), probably a neonatal lizard preserved in the Cretaceous (Alb - Cenomanian border) amber from Myanmar. The authors note that the lizard has a “short and wide skull, large orbits, an elongated and reliable process of the lingual, frontal with parallel edges, starting the prefrontal host, a smaller opener, absent retroarticular process, low presacral and retrosacral vertebrae (from 15 to 17) and extremely short, curled tail, "according to the authors, these traits are indicative of the lizard with Chamaeleonidae. Phylogenetic analysis by the authors showed that the lizard was -ch stem amaeleonid.
Although the exact evolutionary history of color changes in chameleons is still unknown, there is one aspect of the evolutionary history of color changes of a chameleon that has already been fully studied: effects of signal efficiency. The efficiency signal, or how well the signal can be seen against its background, has been shown to correlate directly to the spectral properties of chameleon displays. Dwarf chameleons, a research chameleon, occupies a wide variety of habitats from forests to meadows to shrubs. It has been shown that chameleons in bright areas, as a rule, represent brighter signals, but chameleons in dark areas, as a rule, represent relatively more contrasting signals against their background. This finding suggests that signal efficiency (and thus habitat) influenced the evolution of the chameleon's signaling. Stuart Fox et al. Note that it makes sense that selection on crypsis is not seen to be as important as the choice for signal efficiency, since signals are only output for a short time, chameleons are almost always in muted, mysterious colors.
Chameleons vary greatly in size and body structure, with a maximum length of just 15 mm (0.59 in) in men brukesia micra (one of the world's smallest reptiles) to 68.5 cm (27.0 inches) in the male Furcifer oustaleti . Many of them have a head or face ornament, such as nasal protrusions or horny protrusions in case of Trioceros jacksonii or large crests on the top of the head, like Chamaeleo calyptratus . Many types of sexual dimorphism, and males, are usually much larger than decorated female chameleons.
Typical sizes of chameleon species commonly held in captivity or as pets are:
|Scientific name||Common name||Length (men)||Length (female)||color||Life span (years)|
|Chamaeleo calyptratus||Hidden Chameleon||35-60 cm||25-33 cm||Green and light colors||around 5|
|Trioceros jacksonii||Jackson's Chameleon||23-33 cm||25-33 cm||Green and light colors||5-10|
|Furcifer pardalis||Panther Chameleon||38-53 cm||23-33 cm||dark colors||about 5 (2-3 for maternity women)|
|Rippeleon brevicaudatus||Bearded Dwarf Chameleon||5-8 cm||5-8 cm||Brown, beige, green||3-5|
|spectrum of african dwarf chameleons||Spectral Dwarf Chameleon||8-10 cm||5-10 cm||Tan and gray||3-5|
|African dwarf chameleons temporal||Usambar fossa dwarf chameleon||6-10 cm||5-9 cm||Gray and brown||5-11|
Chameleon legs are highly adapted to wood locomotion, and species such as Chamaeleo namaquensis who re-adopted the earthly habit retained the same foot morphology with minor changes. On each leg, five distinctly distinguished fingers are grouped in two bunches. The toes in each head are connected in a flattened group, either two or three, giving each leg a forceps-like appearance. On the front legs, the outer, lateral, group contains two fingers, while the inner, medial, group contains three. On the hind legs, this arrangement is inverted, the medial group containing two toes, and the lateral group of three. These specialized legs allow the chameleon to grip tightly on narrow or roughened twigs. In addition, each toe is provided with a sharp claw to allow traction on surfaces such as the cortex when lifting. It is common to designate chameleon legs as didactyl or zygodactyl, although neither member is completely satisfactory, and both are used in the description of completely different legs, such as the zygodactyl leg of parrots or didactyl legs of laziness or ostriches, none of which is significantly like a chameleon legs. Although "zygodactyl" is a reasonably descriptive chameleon of foot anatomy, their foot structure does not resemble parrots to which the term was first applied. As for didactyly, chameleons obviously have five toes on each foot, not two.
Some chameleons have a crest of small spikes running along the spine from the proximal part of the tail to the neck, as the degree and size of the spikes depend on the species and individuals. These spikes help break down the final outline of the chameleon, which helps him when trying to fit into the background.
Chameleons have the most distinctive eyes of any reptile. The upper and lower eyelids are connected with only a point eyelid large enough for the student to see to the end. Each eye can rotate independently and focus, allowing the chameleon to observe two different objects simultaneously. This gives them full 360-degree arcs of vision around their bodies. Prey is sought through a monocular of depth of perception, rather than stereopsis. Chameleons have very good eyesight for reptiles, allowing them to see small insects at a distance of 5-10 meters. In fact, chameleons have the largest increase (per size) of any vertebrate.
Like snakes, chameleons have no outer or middle ear, so neither opening the ear nor eardrum. However, chameleons are not deaf: they can detect sound frequencies in the range of 200-600 Hz.
Chameleons can see in visible and ultraviolet light. Chameleons exposed to ultraviolet light show an increase in social levels of behavior and activity, are more prone to bask and feed, and are also more likely to reproduce, as it has a positive effect on the pineal gland.
All chameleons are mostly insectivores, feeding on ballistic projection of their long tongues from their mouths to capture prey located at some distance. Although the languages of the chameleons are generally considered to be one and a half to two times the length of their body (their length excluding the tail), small chameleons have recently been found (as small species and smaller individuals of the same species) to have a proportionately larger tongue devices and their larger counterparts. Thus, small chameleons are able to project their tongues over long distances than larger chameleons, which are the subject of most studies and estimates of the length of the tongue, and can project their tongues more than twice their body length.
The device of the tongue chameleon consists of a highly modified hyoid bone, tongue muscles and collagen elements. The hyoid bone has an elongated, parallel-sided protrusion, called the entoglossal process, over which the tubular muscle, the muscle accelerator, sits. The muscle accelerator contracts around the entoglossal process and is responsible for creating work for projecting the power of the tongue, both directly and through loading collagen elements located between the entoglossal process and the muscle accelerator. The tongue retractor, then hyoglossus, connects the sublingual and accelerator muscles, and is responsible for drawing the tongue back into the mouth of the following projections of the tongue.
Projection language occurs at very high productivity, reaching production in as little as 0.07 seconds, when launched in accelerations exceeding 41 g . The force with which the tongue starts, as you know, exceeds 3000 W kg -1, exceeds what the muscles are able to produce, which indicates the presence of an elastic power amplifier to the projection power of the tongue. The recoil of the elastic elements in the device of the tongue is thus responsible for a large percentage of the total productivity of the projection of the tongue.
One of the consequences of the inclusion of an elastic return mechanism to the projection mechanism of the tongue with respect to thermal insensitivity of the projection of the tongue relative to the retraction tongue, which is powered by muscle contractions at rest, and is largely thermosensitive. While other ectothermic animals become lethargic, as their body temperature decreases, due to a decrease in the speed of contractile muscles, chameleons are able to project their tongues at high productivity even at low body temperatures. The thermal sensitivity of the tongue retraction in the chameleons, however, is not a problem, since chameleons have a very effective mechanism for carrying them out after the tongue comes into contact with it, including surface phenomena such as wet adhesion and blockage, as well also suction. The thermal insensitivity of the tongue projection, thus, allows the chameleons to eat effectively on a cold morning before being able to behaviorally raise their body temperature through thermoregulation, while other sympatric species of lizards are still inactive, probably temporarily expanding their thermal niche as a result.
Some species of chameleons have bones that glow when exposed to ultraviolet light, also known as biogenic fluorescence. Some 31 different kinds Calumma chameleons all growing in Madagascar are displayed in this fluorescence CT scan. The bones emitted a bright blue glow, and can even shine through four layers of skin chameleon. It was found that the face, in order to have a different shine, appears in the form of points otherwise known as tubercles on the facial bones. The results of the glow from the proteins, pigments, chitin and other materials that make up the skeleton of the chameleon, possibly giving the Chameleons a secondary signaling system that does not interfere with their color change ability, and may have evolved from sexual selection.
Distribution and habitat
Chameleons mainly live in mainland sub-Saharan Africa and on the island of Madagascar, although some species live in North Africa, Southern Europe, the Middle East, southern India, Sri Lanka, as well as several small islands in the western Indian Ocean . There are introduced wild populations of veiled and Jackson chameleons in Hawaii, and individual pockets of Jackson's feral chameleons have been recorded in California and Florida.
Chameleons live all kinds of tropical and mountain rainforests, savannas, and sometimes deserts and steppes. Typical chameleons from the subfamily Chamaeleoninae are arboreal, as a rule, live on trees or shrubs, although some of them (in particular, the desert chameleon) are partially or largely terrestrial. Most species from the Brookesiinae subfamily, which includes genera brukesia , Rippeleon and african dwarf chameleons live low vegetation or on the ground among fallen leaves. Many species of chameleons are endangered. The decline in chameleon numbers is due to habitat loss.
Chameleons are mainly oviparous, some of them ovoviviparous.
In egg-laying species, eggs are laid three to six weeks after copulation. The female digs a hole - from 10-30 cm (4-12 inches), deep depending on the species - and lays eggs. Coupling dimensions vary significantly depending on the type. Small brukesia the species can only lay two to four eggs, while large veiled chameleons ( Chamaeleo calyptratus ), as you know, lay a vise of 20-200 (veiled chameleons) and 10-40 (Panther chameleons) eggs. Clutch dimensions can also vary significantly depending on the same type. Eggs are usually hatched after four to 12 months, again depending on the species. Parsons Chameleon Eggs ( Calumma parsonii ), a species that is rarely found in captivity, is believed to take more than 24 months to hatch.
In ovoviviparous species such as the Jackson chameleon ( Trioceros jacksonii ) have a five to seven month pregnancy period. Each young chameleon is born in the sticky transparent membrane of its yolk. Mother presses each egg on the branch where he sticks. Membrane bursts and the hatched chameleon are freed and rise away to hunt for themselves and hide from predators. A female can have up to 30 live young from one pregnancy.
Chameleons usually eat insects, but larger species, such as the common chameleon, can also take other lizards and young birds. The range of diets can be seen from the following examples:
- Veiled Chameleon Chamaeleo calyptratus from Arabia, is an insectivore, but eats sheets when other sources of water are absent. It can be saved on a diet of crickets. They can eat as much as 15-50 large crickets per day.
- Jackson's Chameleon ( Trioceros jacksonii ) from Kenya and northern Tanzania eats a wide variety of small animals, including ant, butterfly, caterpillar, snail, worm, lizard, gecko, amphibian and other chameleon, as well as plant materials such as leaves, tender shoots and berries. It can be stored on a mixed diet, including cabbage, dandelion leaves, lettuce, bananas, tomatoes, apples, crickets and waxworms.
- A common chameleon in Europe, North Africa and the Middle East, Chameleon Chamaeleo , mainly eats wasps and praying mantises, such arthropods form more than three-quarters of their diet. Some experts advise that a common chameleon should not be fed exclusively to crickets, they should be no more than half the diet, with the rest a mixture of waxworms, earthworms, grasshoppers, flies and plant materials such as green leaves, oats, and fruits.
- Temperature affects the amount of food eaten.
- Some chameleons, like a chameleon from Madagascar, regulate their vitamin D3 levels, of which their insect diet is a bad source, exposing itself to sunlight, as its UV - components increase internal production.
Chameleons parasitize worm nematodes, including threadworms (Filarioidea). Threadworms can be transmitted through insect bites such as ticks and mosquitoes. Other roundworms are transmitted through food from contaminated roundworm eggs, larvae burrow through the intestinal wall into the bloodstream.
Chameleons are prone to several protozoan parasites, such as Plasmodium that causes malaria, Trypanosoma that causes sleeping sickness, and Leishmania that causes leishmaniasis.
Chameleons are susceptible to parasitism from coccidia, including genera Chooleoeimeria , Eimeria , and Isospora .