Cape dwarf chameleon | |
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moulting male | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Iguania |
Family: | Chamaeleonidae |
Genus: | Bradypodion |
Species: | B. pumilum |
Binomial name | |
Bradypodion pumilum (Gmelin, 1789) | |
The Cape dwarf chameleon (Bradypodion pumilum) is a chameleon native to the South African province of the Western Cape, where it is restricted to the region around Cape Town.
As with most chameleons, its tongue is twice the length of its body and it can be shot out of its mouth using a special muscle in the jaw. This gives the chameleon the ability to catch insects some distance away.
The Cape dwarf chameleon grows to over 15 cm (5.9 in) in length, including the tail, with males and females reaching similar adult sizes. They are ovoviviparous, but examination in controlled captivity has shown the very soft egg-like membrane around the young is discarded immediately on birth. The young resemble miniature versions of the adults, with muted colours, and typically reach no more than 2 cm in length at birth. Adults can vary quite significantly in colour variety, saturation and pattern, some appearing much more vibrant than others. Like most chameleons, the tail is prehensile, and the feet are well evolved to grasping twigs, with minute claws on the end that improve grip.
Normally very slow moving, chameleons have a characteristic shake, which may make them look more like leaves to prey and predators. When provoked, they can speed up to several centimetres a second. When further provoked, they may inflate themselves, hiss, change colour dramatically, and bite. They do not have sharp teeth, so their bites rarely inflict more than a slight pinch.
Male and female are difficult to differentiate. However males tend to have brighter colours, slightly larger head crests, and slightly narrower stomach area around the hips.
The Cape dwarf chameleon is classified as a medium-sized chameleon with an average adult body size of 50–70 mm body size. This species has a restricted distribution within regions of southwestern South Africa that receive rainfall during winter months. This species is viviparous, meaning it gives live birth rather than eggs, and can have one to several clutches of about 10-15 offspring in any given year. Mortality rates of neonates are expected to be high due to an intense reproduction schedule and a high fecundity rate. [3]
Different populations within Cape dwarf chameleons were found to have different preferences regarding perch diameter. The two main populations, Kogelberg and Stellenbosch, were seen to have different behavior. Kogelberg tended to use perches that were significantly wider on average than perches used by the Stellenbosch site which chose perches by random. Hand size has a direct correlation with grip strength on both broad and narrow dowels, rod-like structures, in both populations. The longer the tail length, the greater the strength. This species prefers to sleep on perches of specific diameters that correspond to their specific morphology. Animals from habitats characterized by wider perches are also stronger than their counterparts living in habitats with narrow branches. This has led to sexual selection for chameleons with specific traits like hand size and tail length. [4]
Bradypodion pumilum has two ecomorphs: a large, brightly coloured, ornate version often found in closed habitats, and a small, dull version with less ornamentation often found in open vegetation. Casque size is known to be used to communicate fighting ability, but it is yet to be known whether this size is an honest signal and if it is related to bite force. Bite force is significantly related to head size and the best way to tell the strength of the bite force is measuring the head width. [5] Open habitat males tend to have larger heads thus having stronger bite force. Larger chameleons have a high casque (parietal crest) and are brightly coloured with pink patches on their flank. The smaller chameleons found in open habitats have reduced casques and lack flank colour patches at all. Battles between males can lead to severe injuries through biting. [6]
In the past, most South African dwarf chameleons were considered a subspecies of the Cape species [7] This is now known to be wrong, however; B. pumilum does not appear to have any particularly close living relatives. Like the Knysna dwarf chameleon, it seems to be a basal offshoot of the ancestral stock, which gave rise to all Bradypodion species. [8]
Cape dwarf chameleons have a much higher survival rate in a metropolitan area if they are bigger in size. Their survival rate was dependent on body size, and the larger the size, the greater the chance that the individual would survive a ten-day period. Larger, older chameleons tend to be more sedentary compared to the smaller younger ones which means that the larger ones likely have smaller home ranges. Smaller chameleons inhabit grasses while larger chameleons are found mainly in bushes and trees. This is territorial, because it is believed that larger males would cannibalize smaller ones intruding on their territory. An alternative thought is that the smaller chameleons simply do not have big enough limbs to grasp larger branches correctly. When fighting contests occur, the outcome is influenced by the height of the ornamental casque, the relative size of the pink patch in the center of the flank, and previous experience. The ornamental casque is the protruding head piece of the chameleon, usually with a rounded end. The height of this piece is an honest signal to other male chameleons representing its total size. Similarly with the pink patch in the center of the flank, this is an honest signal showing that the chameleon has a healthy diet correlating to the strength of the individual. [9] The turnover rate in males is thought to be higher than females. [10]
When it comes to foraging, males and juveniles are more active than females. Females are only equally or more active than males during the reproductive season. Males may be more active due to seeking mates and defending territories. Bradypodion pumilum is a sit-and-wait forager which means they will rarely move and wait for prey to cross their paths, only then striking out. Low rates of prey capture are often seen in this species. [11]
The Cape dwarf chameleon is restricted to the area around Cape Town, the Boland, and the mountainous coastline as far as Agulhas.
Like many other reptiles, chameleons are poikilotherms meaning their body temperature is completely dependent on environmental temperature. A large number of lizards are expected to be affected by climate change in the near future, especially in Southern Africa where this species is found. If temperatures rise by 1-3 degrees Celsius, then it is expected that Cape dwarf chameleon running speed will increase as well. Although speed would be better, bite and grip force would become worse. Chameleons are adapted to current habitat temperatures and conditions, but shifting to a higher temperature would actually benefit some of their traits and abilities. This shows that future persistence of this species is very likely even with the advancement of global warming. [12]
This species inhabits a range of different habitats and vegetation types, from fynbos and renosterveld, to indigenous Afrotemperate forest and wetlands.
It is less common in extremely fire-prone and low-growing fynbos, and in open sandy or rocky areas. It is more usually found in areas such as river valleys, which are sheltered to some degree from the region's seasonal fires, and where more dense vegetation has developed. It prefers certain plant species to reside on too, especially favouring Restios. This adaptable species has also diversified into different forms and colours, depending on their habitat. Those that live in open, low-lying fynbos vegetation tend to be smaller and dull-coloured with smaller crests. Those in denser, closed vegetation areas tend to be larger and brightly coloured, with a longer tail and larger casque.
In the wild, its predators are mainly snakes and predatory birds such as fiscal shrikes. [13]
When looking at open habitats, chameleons with smaller body sizes are favored. Differences between habitats include certain traits found in the chameleons. This includes limbs, feet, tail, and head width. Open habitats commonly see longer limbs but smaller feet compared to chameleons found in closed habitats. Smaller feet in the open habitat are more accustomed to grasping the narrower branches. Natural and sexual selection in open and closed habitats have different intensities which directly affects the morphological variation found within the species. [14]
The Cape dwarf chameleon is currently experiencing habitat loss and fragmentation of its natural habitat through causes such as urbanization and agriculture. The historical habitat of Bradypodion pumilum has recently become severely fragmented due to intense urbanization and agricultural transformation. This trend is continuing with approximately 6.5 square kilometers of undeveloped land becoming lost to transformation in the Cape Town municipal area per year. Additional losses are expected to occur because of rapid climatic changes near Cape Town which is where the species is primarily distributed. In urban areas, Cape dwarf chameleons are limited to planted vegetation, usually nonindigenous species, and patches of highly disturbed habitat. Populations are often found living in the overgrowth of exotic vegetation on road verges, abandoned urban ground, riverine thickets, or residential areas. Part of the species distribution lies in habitats that are protected by provincial parks, national parks, and private reserves. This protected area only amounts to 40% of the total area of occupancy. Most of the shrubland found in these protected areas is fire-prone, and natural fires are known to be detrimental to dwarf chameleon populations. [15]
With much of their former habitat now covered in suburbs, this little species has shown itself partially adaptable to suburban gardens. They can serve as a natural insect control for gardens. However, not all gardens are suitable.
Chameleons survive only in sunny gardens with much varied bushy vegetation.
Direct sunlight is a prerequisite for cold-blooded reptiles like chameleons. Chameleons also require vegetation for a habitat—preferably with foliage they can easily grasp with their small claws, and perch on. Therefore, most suitable are bushes and small trees with some fine foliage or thin twigs for climbing. Favoured local shrub species include: Restio reeds, daisy bushes, Leonotis bushes, Cape Honeysuckle, Plumbago, Bitou bushes, Psoralea pinnata and many others. Favoured trees are those which provide low and accessible foliage, such as Karee trees, Willows, Pepper trees, Virgilia and others.
Terrains with no suitable habitat include lawns, paved areas, brickwork, or higher trees with trunks too wide for chameleons to climb. Foliage should also not be pruned or trimmed, or exposed to insecticide poisons, as this usually kills or injures chameleons. [16]
Chameleons naturally wander and, in suburbs with smaller gardens, they also avoid properties that don't connect to larger "green corridors" that join several properties. [17] [18]
In urban areas, its predators are mainly domestic cats. Cats are a non-native, introduced predator that chameleons are defenceless against. More importantly, the growing density of cats kept in suburban areas causes an unnaturally high ratio of predators to prey, leading to the collapse of populations of chameleons and many other species. Other predators include a range of urban and introduced bird species such as crows.
Certain gardening practices such as using insecticides or hedge trimmers can also kill off urban populations. Garden clearing removes habitat, especially when greenery is replaced with paving, brickwork or lawns. Occasionally chameleons are also known to transported on garden waste, to waste disposal sites. [19] [20] [21]
People often think chameleons change their colour for camouflage so to blend into the environment, but this is false. [22] Chameleons change colour as a way of expressing mood and communicating as well as to thermoregulate, turning a darker colour to absorb more heat or very pale pastel colours to reflect light and absorb less heat.
Courtship involves small, quick head twitches by the male, who exhibits brighter courtship colours. If the female rejects the male's advances, she assumes a much darker colour, sway from side to side, and often opens her mouth threateningly. Darker colours are often associated with stress, and lighter colours with relaxation or sleep.
During the night, the species tends to move higher, to the tips of branches (nocturnal predators are primarily terrestrial) and assume a white colour when they sleep. During the day they spend more time lower down in denser vegetation (daytime predators include several species of birds).
They feed primarily on small insects and other arthropods. They drink by licking dew or rain drops from leaves or other surfaces. [23]
The taxonomy of Bradypodion is based largely on morphological characteristics. There is a lack of a comprehensive assessment of sexual ontogenetic and population variation of these characters. Some common characters used to define Bradypodion species is casque development, scale shape and size in crests, lateral tubercles, and others. [24]
While it is not normally legal to keep these chameleons, it is possible to obtain special permission from the South African government to do so. These chameleons are better admired than handled. However, taming is possible through gentle and consistent (almost daily) contact, allowing trust to build up. This is typically achieved through careful and slow hand-based feeding of flies, small spiders, grasshoppers, etc. In cold weather, a sensitively handled B. pumilum commonly becomes eager to perch on a human hand for the warmth. To maintain them out of their natural environment requires advanced skills and is a demanding project; they require the right amount and type of ultraviolet exposure and large supplies of specific types of live food that are not easy to supply. They also require moisture, even just tap water sprayed gently onto the foliage with a hose.
In most urban environments, the amount of naturally occurring suitable insect food is insufficient. They should remain outdoors where they are able to regulate their own body temperatures using sunlight (like most reptiles, they die if deprived of, or overexposed to the sun).
Cat owners should be aware that domestic cats are introduced predators, and usually kill all chameleons in the immediate area. Consequently, one should not bring chameleons into a garden frequented by cats. It also is important to be cautious of the activity of shrikes, in particular the southern fiscal, which, if they get into the chameleon-hunting habit, will rapidly strip a garden.
Chameleons or chamaeleons 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 colors, being capable of shifting to different hues and degrees of brightness. The large number of species in the family exhibit considerable variability in their capacity to change color. For some, it is more of a shift of brightness ; for others, a plethora of color-combinations can be seen.
Bradypodion is a genus of chameleons in the family Chamaeleonidae, collectively called South African dwarf chameleons. All species are found in South Africa and most are endemic to this country, but a few can also be found in Eswatini, Lesotho, southernmost Namibia and possibly southernmost Mozambique. They are quite small chameleons where the different species often can be difficult to separate by appearance, although exact location and the intense breeding colours of males are useful for their identification. They are arboreal, but some species are mostly found low in the vegetation.
Kinyongia is a genus of chameleons found in montane and sub-montane areas in Kenya, Tanzania, Uganda, Rwanda, Burundi, and far eastern DR Congo. They are restricted to forests, woodlands and other wooded habitats, and many species have very small geographic ranges. In most species, at least the males have horns or knobs on their noses. As typical of most chameleons, Kinyongia are oviparous.
Currently, two species are placed in the recently established genus Nadzikambia. They are plesiomorphic, small chameleons from the Ruo Gorge forest on Mount Mulanje in Malawi and Mount Mabu in Mozambique.
Setaro's dwarf chameleon is a species of lizard in the family Chamaeleonidae.
Smith's dwarf chameleon, also known as the Elandsberg dwarf chameleon, is a species of lizard in the family Chamaeleonidae endemic to Fynbos in South Africa's Eastern Cape. As in several species of chameleons in the genus Bradypodion, the Smith's dwarf chameleon can use its color-changing ability to actively camouflage itself depending on the vision of the specific predator species by which it is being threatened.
The Transkei dwarf chameleon or Pondo dwarf chameleon is a chameleon endemic to the Eastern Cape Province of South Africa.
The Robertson dwarf chameleon, also known as the Little Karoo dwarf chameleon, is a chameleon in the genus Bradypodion. It is found in the dry Fynbos and Renosterveld shrub vegetation, in the centre of the Western Cape province, South Africa.
The Swartberg dwarf chameleon is a species of chameleon endemic to South Africa.
The Knysna dwarf chameleon is a species of dwarf chameleon in the Bradypodion genus that is endemic to South Africa. It is a forest dweller, found only in a limited range in the afromontane forests near Knysna, South Africa, and in certain surrounding areas.
The black-headed dwarf chameleon is a lizard of the family Chamaeleonidae endemic to KwaZulu-Natal, South Africa. It is also known as the KwaZulu dwarf chamaeleon and Durban dwarf chameleon.
Bradypodion ventrale, the southern dwarf chameleon, occurs in the Eastern Cape, South Africa. It is also known as the eastern Cape dwarf chameleon. It is a relatively large species of dwarf chameleon, reaching lengths of 14 cm (5.5 in). It has a very prominent casque on the back of its head and a long, beard-like throat crest. It lives in dense thickets and shrub, and is usually very difficult to spot because of its colouring. It adapts very well to living in suburban gardens, but domestic cats – being introduced predators – will usually kill all chameleons in the immediate area. Consequently, one should not bring chameleons into a garden which is frequented by cats. It gives birth to litters of between 10 and 20 babies in the summer.
The Drakensberg dwarf chameleon occurs in the Drakensberg, South Africa, between the latitudes of 27°45′ and 29°15′. Bright green dwarf chameleons found in the Drakensberg south of 29°15′ are now known to be more closely related to the Natal Midlands dwarf chameleon and may yet be described as a separate species.
The Namaqua dwarf chameleon or the western dwarf chameleon occurs in beach vegetation, along the west coast of South Africa and Namibia.
The Karoo dwarf chameleon is a chameleon native to South Africa. It is about 14 cm (6 in) long, mostly colored grey and brown, sometimes olive. The thin skin around the throat is yellow, and it has conical scales along the spine.
The Natal Midlands dwarf chameleon is a chameleon native to woodland habitat in the inland Midlands area of the South African province of KwaZulu-Natal.
Chamaeleoninae is the nominotypical subfamily of chameleons. The Family Chamaeleonidae was divided into two subfamilies, Brookesiinae and Chamaeleoninae, by Klaver and Böhme in 1986. Since its erection in 1986, 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 a monophyletic group. While some authorities have previously preferred to use the subfamilial classification on the basis of the absence of evidence principal, 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 the Brookesiinae subfamily, with all other genera being placed in Chamaeleoninae.
The Mlanje Mountain chameleon is one of two species in the genus Nadzikambia. It is a plesiomorphic, small chameleon from the Ruo Gorge forest on Mount Mulanje in Malawi.
Meroles squamulosa is a species of African lizard originally placed in the genus Ichnotropis, however phylogenetic evidence moves this species to the genus Meroles. The species is commonly called the common rough-scaled lizard or savanna lizard. It is largely found in southern Africa. These lizards are terrestrial and found in the range of mesic savannah. The common rough-scaled lizard is medium in size and well distributed in parts of Namibia, Botswana, Zimbabwe, Angola, Tanzania, and Zambia.
A casque is an anatomical feature found in some species of birds, reptiles, and amphibians. In birds, it is an enlargement of the bones of the upper mandible or the skull, either on the front of the face, or the top of the head, or both. The casque has been hypothesized to serve as a visual cue to a bird's sex, state of maturity, or social status; as reinforcement to the beak's structure; or as a resonance chamber, enhancing calls. In addition, they may be used in combat with other members of the same species, in the gathering of food, or in thermoregulation.