178-507: Megalobatrachus davidianus (Reviewed by Liu, 1950) The Chinese giant salamander ( Andrias davidianus ) is one of the largest salamanders and one of the largest amphibians in the world. It is fully aquatic, and is endemic to rocky mountain streams and lakes in the Yangtze river basin of central China . It has also been introduced to Kyoto Prefecture in Japan , and possibly to Taiwan . It
356-414: A bow hook is one of the preferred methods used by hunters to catch the salamander. This hunting tool is made with a combination of bamboo and sharp hooks baited with frogs or smaller fish. This is used to capture the salamander and keep it alive. Some hunters use pesticides to kill the salamander. Farmers often poach wild salamanders to stock their breeding programs, while others are hunted as food. In
534-478: A buffalo in Jamestown, North Dakota , and inspiration for Herman Melville 's novel Moby-Dick , a sperm whale known as Mocha Dick . The most important pigments that determine plumage colouration in birds are melanines and carotenoids. The latter are ingested in food and transformed into colour pigments by enzymes. Aberrations in this pigmentation are mostly caused by food deficiencies and usually do not have
712-428: A junior synonym ) – a name otherwise restricted to an extinct species described from Swiss fossils. It has also been given the moniker of "living fossil" for being part of the family Cryptobranchidae which dates back 170 million years. It is one of only five to six known extant species of the family, the others being the slightly smaller, but otherwise very similar Japanese giant salamander ( Andrias japonicus ),
890-512: A toque macaque ( M. sinica ), rhesus macaque ( M. mulatta ), and bonnet macaque ( M. radiata ). Albinism was observed in jungle cats ( Felis chaus ) and jackals ( Canis aureus ) along the coastline of the southern Western Ghats (Kerala and Kanyakumari coast, India). Albinism was observed in jungle cats from the Amaravila area of Trivandrum district in the Kerala State. Albinism in jackals
1068-530: A "semi-lethal mutation". Pigmentation disorders such as albinism are occasionally associated with hearing impairments in mice, rats, guinea pigs and cats. Intentionally bred albinistic strains of some animal species are commonly used as model organisms in biomedical research and also as pets. Examples include the BALB/c mouse and Wistar and Sprague Dawley rat strains, laboratory rabbits and ferrets. Some researchers have argued that albino animals are not always
1246-644: A 2018 study, the Zoological Society of London and the Kunming Institute of Zoology in China reported on their surveys for giant salamanders in 16 Chinese provinces over four years. The researchers had been unable to confirm survival of wild salamanders at any of the 97 sites they surveyed. The study also brought up worries that commercial farms and conservation programs were crossbreeding what they described as five distinct species of Chinese giant salamanders. All
1424-634: A Chinese giant salamander on display. Since May 2014, 33 Chinese giant salamanders, including three adults, have been held in Prague Zoo . The main attraction is the largest individual in Europe, which is 155 cm (5 ft 1 in) long. In the past, the Chinese giant salamander was fairly common and widespread in China. Since the 1950s, the population has declined rapidly due to habitat destruction and overhunting. It has been listed as Critically Endangered in
1602-450: A bone which usually lies along the upper cheek region of most salamanders, which gives them a much stronger bite force. The bite force of the adult Chinese giant salamander is much stronger than the bite force of the maturing Chinese giant salamander due to differences in cranial structure. Chinese giant salamanders esophaguses are made up of four different layers, one of which being a strong muscular tissue used to help move food through to
1780-655: A colour resulting from selective colour absorption . What is perceived as a plant or animal's "colour" is the wavelengths of light that are not absorbed by the pigment, but instead are reflected. Biological pigments include plant pigments and flower pigments . Animals can appear coloured due to two mechanisms, pigments and structural colours . Animals may have both biological pigments and structural colours, for example, some butterflies with white wings. Many animal body-parts, such as skin , eyes , feathers , fur , hair , scales and cuticles, contain pigments in specialized cells called chromatophores . These cells are found in
1958-413: A concealed site in flowing water, and these are usually guarded by an adult, normally the female. Many of the tropical climbing salamanders ( Bolitoglossa ) and lungless salamanders (Plethodontinae) lay a small number of large eggs on land in a well-hidden spot, where they are also guarded by the mother. Some species such as the fire salamanders ( Salamandra ) are ovoviviparous , with the female retaining
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#17328560574702136-490: A condition called agouti , they make multi-coloured individual hairs. The production of melanin occurs in melanocytes in a complex process involving the enzyme tyrosinase . Mammals have a gene that codes for the presence of tyrosinase in cells – called the TYR gene. If this gene is altered or damaged, melanin cannot be reliably produced and the mammal becomes an albino. Besides the TYR gene, several other genes can cause albinism. This
2314-458: A dominant albinism in the rainbow trout . Albinism occurs throughout the animal kingdom. The condition is most commonly seen in birds, reptiles and amphibians, but more rarely seen in mammals and other taxa. It is often difficult to explain occasional occurrences, especially when only one documented incidence has occurred, such as only one albino gorilla and one albino koala . In mammals, albinism occurs once in every 10,000 births, but in birds,
2492-585: A farm in Zhangjiajie , was 1.8 m (5.9 ft) in 2007. At 59 kg (130 lb), both this individual, and a 1.4 m (4.6 ft) long, 52 kg (114 lb) individual found in a remote cave in Chongqing in December 2015, surpassed the species' typically reported maximum weight. The giant salamander is known to vocalize, making barking, whining, hissing, or crying sounds. Some of these vocalizations bear
2670-586: A flash of warning hue on its underside. The red eft, the brightly colored terrestrial juvenile form of the eastern newt ( Notophthalmus viridescens ), is highly poisonous. It is avoided by birds and snakes, and can survive for up to 30 minutes after being swallowed (later being regurgitated). The red salamander ( Pseudotriton ruber ) is a palatable species with a similar coloring to the red eft. Predators that previously fed on it have been shown to avoid it after encountering red efts, an example of Batesian mimicry . Other species exhibit similar mimicry. In California,
2848-531: A fungus, such as Lacazia loboi . Famous albino mammals include Migaloo , a humpback whale living off the coast of Australia; Pinky , a bottlenose dolphin living in and around in Calcasieu Lake , Louisiana; Carolina Snowball, a popular albino bottlenose dolphin displayed at the Miami Seaquarium in the early 1960s; Snowflake , a Barcelona Zoo gorilla , and Mahpiya Ska , ( Sioux for White Cloud),
3026-437: A genetic basis. Well-known examples are flamingos , which owe their distinct pink colour to the presence of red carotenoids in their natural food. When these carotenoids are in short supply, these birds appear white after the next moult . Mutations causing changes in carotenoid-based colour pigments are rare; melanine mutations occur much more frequently. Two types of melanin, eumelanin and phaeomelanin, are present in birds. In
3204-403: A good diagnostic feature with which to distinguish leucistic and albino individuals – the colour of the eye." However, there are multiple forms of albinism – currently seven types recognised for humans – most of which do not result in red or pink pupils. The term "partial albino" is sometimes used in the literature. However, it has been stated that "A common misnomer is 'partial albino' – this
3382-447: A great impact overall due to the massive overhunting of the species. No matter how many members of the species they manage to save through the reserves, the poachers still manage to capture and kill that many more. Although habitat destruction is certainly not assisting in the perpetuation of the species, it is certainly not the biggest obstacle that the Chinese giant salamander faces in its quest to avoid extinction. Like other amphibians,
3560-511: A group of amphibians typically characterized by their lizard -like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela from the group Caudata . Urodela is a scientific Latin term based on the Ancient Greek οὐρά δήλη : ourà dēlē "conspicuous tail". Caudata
3738-416: A hissing sound, while the sirens sometimes produce quiet clicks, and can resort to faint shrieks if attacked. Similar clicking behaviour was observed in two European newts Lissotriton vulgaris and Ichthyosaura alpestris in their aquatic phase. Vocalization in salamanders has been little studied and the purpose of these sounds is presumed to be the startling of predators. Respiration differs among
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#17328560574703916-627: A lack of protection. Albino humans must use an excessive amount of sunscreen, even if the sun is hidden behind the clouds. Animals with albinism may lack protective camouflage in some environments, and are therefore less able to conceal themselves from their predators or prey. However, in other environments albino animals are less likely to be killed, and selection may favor them. The lower survival rate of animals with albinism in certain environments has been documented, however, it has been stated that in studies where animals had many places to hide, predators captured albino and normally coloured animals at
4094-438: A lateral row. This may provide an aposematic signal that makes the spines more visible. When the danger has passed, the ribs retract and the skin heals. Although many salamanders have cryptic colors so as to be unnoticeable, others signal their toxicity by their vivid coloring . Yellow, orange, and red are the colors generally used, often with black for greater contrast. Sometimes, the animal postures if attacked, revealing
4272-429: A length of about 20 cm (8 in) at an age of 3 years. The external gills start to slowly decrease in size around 9 to 16 months, the rate of this phenomenon occurs in relation to the rate of dissolved oxygen, breeding density, water temperatures, and individual differences. Maturity is reached at an age of 5 to 6 years and a length of 40–50 cm (16–20 in). The maximum age reached by Chinese giant salamanders
4450-572: A line on the body from head to tail. It is capable of sensing the slightest vibrations around it with the help of these nodes. Based on a captive study, most activity is from the earlier evening to the early night. Most individuals stop feeding at water temperatures above 20 °C (68 °F) and feeding ceases almost entirely at 28 °C (82 °F). Temperatures of 35 °C (95 °F) are lethal to Chinese giant salamanders. Adult Chinese giant salamanders and maturing Chinese giant salamanders with nonexistent or shrinking gill slits have developed
4628-652: A long body, a laterally flattened tail with dorsal and ventral fins and in some species limb-buds or limbs. Pond-type larvae may have a pair of rod-like balancers on either side of the head, long gill filaments and broad fins. Stream-type larvae are more slender with short gill filaments—in Rhyacotriton and Onychodactylus, and some species in Batrachuperus, the gills and gill rakers are extremely reduced, narrower fins and no balancers, but instead have hind limbs already developed when they hatch. The tadpoles are carnivorous and
4806-420: A medical condition that they were born with" and "a person or animal with white skin and hair and pink eyes" do not include feathers, scales or cuticles of birds, fish and invertebrates, nor do they include plants. Some definitions are too broad to be of much use, e.g. "an animal or plant with a marked deficiency in pigmentation". Other definitions of albinism encompass most of the major animal taxa, but ignore
4984-517: A minute fragment of skin is deadly. In feeding trials, fish, frogs, reptiles, birds, and mammals were all found to be susceptible. Mature adults of some salamander species have "nuptial" glandular tissue in their cloacae , at the base of their tails, on their heads or under their chins. Some females release chemical substances , possibly from the ventral cloacal gland, to attract males, but males do not seem to use pheromones for this purpose. In some plethodonts , males have conspicuous mental glands on
5162-595: A reasonable size. Large species such as the Japanese giant salamander ( Andrias japonicus ) eat crabs, fish, small mammals, amphibians, and aquatic insects. In a study of smaller dusky salamanders ( Desmognathus ) in the Appalachian Mountains , their diet includes earthworms , flies , beetles , beetle larvae, leafhoppers , springtails , moths , spiders , grasshoppers , and mites . Cannibalism sometimes takes place, especially when resources are short or time
5340-499: A recent survey of the species in the Qinghai Province, none were found indicating the population size is at a significantly low number or the species is locally extinct in the province. This is believed to be due to the increased mining in the region. In recent years populations have also declined with an epizootic Ranavirus infection. The disease causes severe hemorrhaging in both juveniles and adult salamanders. The virus
5518-433: A second. In some species, the tongue is attached anteriorly to the floor of the mouth, while in others, it is mounted on a pedicel. It is rendered sticky by secretions of mucus from glands in its tip and on the roof of the mouth. High-speed cinematography shows how the tiger salamander ( Ambystoma tigrinum ) positions itself with its snout close to its prey. Its mouth then gapes widely, the lower jaw remains stationary, and
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5696-678: A short period of time and involves the closing of the gill slits and the loss of structures such as gills and tail fins that are not required as adults. At the same time, eyelids develop, the mouth becomes wider, a tongue appears, and teeth are formed. The aqueous larva emerges onto land as a terrestrial adult. Not all species of salamanders follow this path. Neoteny , also known as paedomorphosis, has been observed in all salamander families, and may be universally possible in all salamander species. In this state, an individual may retain gills or other juvenile features while attaining reproductive maturity. The changes that take place at metamorphosis are under
5874-509: A simplified retinal structure, and in cave dwellers such as the Georgia blind salamander , they are absent or covered with a layer of skin. In amphibious species, the eyes are a compromise and are nearsighted in air and farsighted in water. Fully terrestrial species such as the fire salamander have a flatter lens which can focus over a much wider range of distances. To find their prey, salamanders use trichromatic color vision extending into
6052-407: A small lizard, having a basal tetrapod body form with a cylindrical trunk, four limbs, and a long tail. Except in the family Salamandridae, the head, body, and tail have a number of vertical depressions in the surface which run from the mid-dorsal region to the ventral area and are known as costal grooves . Their function seems to be to help keep the skin moist by channeling water over the surface of
6230-407: A species. These algal blooms also deplete the levels of oxygen in the water, and a lesser supply of oxygen can quite easily hold the potential to kill off many members of the dwindling species. Many efforts have been undertaken to create reserves and faux habitats for the Chinese giant salamander so that they can reproduce without worry of soiled water, but many of these reserves have failed in having
6408-487: A sticky, white skin secretion that repels predators. The average adult salamander weighs 25–30 kg (55–66 lb) and is 1.15 m (3.8 ft) in length. It can reach up to 50 kg (110 lb) in weight and 1.8 m (5.9 ft) in length, making it the second-largest amphibian species, after the South China giant salamander ( Andrias sligoi ). The longest recently documented Chinese giant salamander, kept at
6586-561: A striking resemblance to the crying of a young human child, and as such, it is known in the Chinese language as the "infant fish" (娃娃鱼 / 鲵 - Wáwáyú/ ní). The Chinese giant salamander has been recorded feeding on insects, millipedes , horsehair worms , amphibians (both frogs and salamanders), freshwater crabs , shrimp, fish (such as Saurogobio and Cobitis ), and Asiatic water shrew . Presumably ingested by mistake, plant material and gravel have also been found in their stomachs. Cannibalism
6764-465: A system for bidirectional flow suction feeding under water. They start by moving to their prey very slowly, then once close enough to them the Chinese giant salamander abruptly gapes its mouth open. The gaping motion of their mouth causes a great increase in the velocity of the water straight ahead of them compared to water coming in from the sides of their mouth. This is possible because of their large, wide, and flat upper and lower jaws. This process causes
6942-437: A top predator since the introduction of locally exotic species such as Nile tilapia and carp. Tilapia and carp directly compete with axolotls by consuming their eggs, larvae, and juveniles. Climate change has also immensely affected axolotls and their populations throughout the southern Mexico area. Due to its proximity to Mexico City , officials are currently working on programs at Lake Xochimilco to bring in tourism and educate
7120-496: A white beak, white plumage, non-coloured skin, white talons and pink or red eyes. Albinism is only seen in about 1 of every 1,800 birds. The two most common species of albino birds are the common house martin and the American robin . Famous albino birds include " Snowdrop ", a Bristol Zoo penguin . In one study, albinism in birds has been categorised according to the extent of pigment absence. However, it has been argued that
7298-449: A wide range of animals including amphibians , fish , reptiles , crustaceans and cephalopods . Mammals and birds , in contrast, have a class of cells called melanocytes for colouration. The term chromatophore can also refer to coloured, membrane-associated vesicles found in some forms of photosynthetic bacteria . Chromatophores are largely responsible for generating skin and eye colour in poikilothermic animals and are generated in
Chinese giant salamander - Misplaced Pages Continue
7476-458: Is a clearly defined set of seven types of genetic mutations which reduce or completely prevent the synthesis of eumelanin or pheomelanin , resulting in reduced pigmentation. Type I oculocutaneous albinism (OCA1a) is the form most commonly recognised as 'albino' as this results in a complete absence of melanin in the skin, hair/fur/feathers, and pink pupils, however this has led many to assume that all albinos are pure white with pink pupils, which
7654-404: Is a common misconception that all albino animals have characteristic pink or red eyes (resulting from the lack of pigment in the iris allowing the blood vessels of the retina to be visible); this is not the case for some forms of albinism. Familiar albino animals include in-bred strains of laboratory animals (rats, mice and rabbits), but populations of naturally occurring albino animals exist in
7832-520: Is advanced into the salamander's mouth, the teeth tips relax and bend in the same direction, encouraging movement toward the throat, and resisting the prey's escape. Many salamanders have patches of teeth attached to the vomer and the palatine bones in the roof of the mouth, and these help to retain prey. All types of teeth are resorbed and replaced at intervals throughout the animal's life. A terrestrial salamander catches its prey by flicking out its sticky tongue in an action that takes less than half
8010-433: Is also a great factor in the habitat destruction of the Chinese giant salamander; the immense decline in their population can be traced to, among the other major problems of over-hunting and failed conservation efforts, the tainting of the water that they live in. Mining activity in particular in areas near their streams often causes runoff that sullies the water, and farming—and all of the pesticides and chemicals that affect
8188-592: Is also the museum's mascot. As of 2019, London Zoo holds four individuals (one of them on display) that were seized from an illegal importation of amphibians in 2016. A medium-sized individual, approximately 0.9 m (3 ft) long, was kept for several years at the Steinhart Aquarium in San Francisco , California , and is now on display again in the "Water Planet" section of the new California Academy of Sciences building. There are also two in residence at
8366-555: Is another large, long-lived species with dwindling numbers and fewer juveniles reaching maturity than previously. Another alarming finding is the increase in abnormalities in up to 90% of the hellbender population in the Spring River watershed in Arkansas. Habitat loss, silting of streams, pollution and disease have all been implicated in the decline and a captive breeding programme at Saint Louis Zoo has been successfully established. Of
8544-640: Is because other hormones and proteins are involved in melanin production, the presence of which is genetically determined. In mice, a total of 100 genes are known to affect albinism. Most forms of albinism follow a recessive pattern of inheritance. However, this is not always the case. In palomino horses, genes coding for coat whiteness are dominant, and this is also true for several arctic mammals who possess dominant white colors which are pseudo-albinistic. However, these mammals differ from truly recessive albinos in that they still produce tyrosinase , and have normal eye pigmentation. In Japan, research has identified
8722-453: Is being undertaken to assess the status of these salamanders, and to better understand the factors involved in their population declines, with a view to taking action. Ambystoma mexicanum , an aquatic salamander, is a species protected under the Mexican UMA (Unit for Management and conservation of wildlife) as of April 1994. Another detrimental factor is that the axolotl lost their role as
8900-548: Is considered critically endangered in the wild due to habitat loss , pollution, and overcollection, as it is considered a delicacy and used in traditional Chinese medicine . On farms in central China, it is extensively farmed and sometimes bred, although many of the salamanders on the farms are caught in the wild. It has been listed as one of the top-10 "focal species" in 2008 by the Evolutionarily Distinct and Globally Endangered project. The Chinese giant salamander
9078-680: Is considered to be a " living fossil ". Although protected under Chinese law and CITES Appendix I, the wild population has declined by more than an estimated 80% since the 1950s. Although traditionally recognized as one of two living species of Andrias salamander in Asia, the other being the Japanese giant salamander , evidence indicates that the Chinese giant salamander may be composed of at least five cryptic species , further compounding each individual species' endangerment. The correct scientific name of this species has been argued to be Andrias scheuchzeri (in which case Andrias davidianus would be
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#17328560574709256-510: Is frequent; in a study of 79 specimens from the Qinling – Dabashan range, the stomach content of five included remains of other Chinese giant salamanders and this made up 28% of the combined weight of all food items in the study. The most frequent items in the same study were freshwater crabs (found in 19 specimens), which made up 23% of the combined weight of all food items. It has very poor eyesight, so it depends on special sensory nodes that run in
9434-482: Is guarded by the male until the eggs hatch after 50–60 days. They have a variety of different courtship displays including knocking bellies, leaning side-to-side, riding, mouth-to-mouth posturing, chasing, rolling over, inviting, and cohabiting. When laid, the eggs measure 7–8 mm (0.28–0.31 in) in diameter, but they increase to about double that size by absorbing water. When hatching, the larvae are about 3 cm (1.2 in) long and external gills remain until
9612-604: Is internal. As a general rule, salamanders with internal fertilization have indirect sperm transfer, but in species like the Sardinian brook salamander , the Corsican brook salamander , the Caucasian salamander and the Pyrenean brook salamander , the male transfer his sperm directly into the female cloaca. For the species with indirect sperm transfer, the male deposits a spermatophore on
9790-417: Is larger than that of the female, is used during the amplexus embrace to propel the mating couple to a secluded location. In terrestrial species, the tail moves to counterbalance the animal as it runs, while in the arboreal salamander and other tree-climbing species, it is prehensile . The tail is also used by certain plethodontid salamanders that can jump, to help launch themselves into the air. The tail
9968-435: Is limited. Tiger salamander tadpoles in ephemeral pools sometimes resort to eating each other, and are seemingly able to target unrelated individuals. Adult blackbelly salamanders ( Desmognathus quadramaculatus ) prey on adults and young of other species of salamanders, while their larvae sometimes cannibalise smaller larvae. Most species of salamander have small teeth in both their upper and lower jaws. Unlike frogs , even
10146-422: Is listed as a critically endangered species. It has experienced a drastic population decline, which is estimated to be more than 80% in the last 3 generations and due to human causes. Human consumption is the main threat to the Chinese giant salamander. They are considered to be a luxury food item and source of traditional medicines in China. According to a recent study, 90% of the Chinese giant salamanders' habitat
10324-465: Is not just limited to limbs but extends to vital organs such as the heart, jaw, and parts of the spinal cord, showing their uniqueness compared to different types of vertebrates. This ability is most remarkable for occurring without any type of scarring. This has made salamanders an invaluable model organism in scientific research aimed at understanding and achieving regenerative processes for medical advancements in human and animal biology. Members of
10502-549: Is not possible since albinism affects the whole plumage of a bird, not just part" and the definition of albinism precludes the possibility of "partial albinism" in which a mostly white bird shows some form of melanin pigmentation. "It is simply impossible, just like being 'partially pregnant' ". Conditions that are commonly termed "partial albino" include neural crest disorders such as piebaldism , Waardenburg syndrome , or other depigmentation conditions such as vitiligo . These conditions result from fundamentally different causes to
10680-530: Is not the case. In plants, albinism is characterised by partial or complete loss of chlorophyll pigments and incomplete differentiation of chloroplast membranes. Albinism in plants interferes with photosynthesis , which can reduce survivability. Some plant variations may have white flowers or other parts. However, these plants are not totally devoid of chlorophyll. Terms associated with this phenomenon are "hypochromia" and "albiflora". Biological pigments are substances produced by living organisms that have
10858-831: Is now highly fragmented. Their range spans the area from Qinghai east to Jiangsu and south to Sichuan , Guangxi , and Guangdong ; notably in the basins of the Yangtze , Yellow , and Pearl Rivers . One clade is from the Pearl River basin (at least in Guangxi), two from the Yellow River basin, one from the Yangtze River basin (at least in Chongqing and Guizhou ), and the final from the Qiantang River (at least in Anhui ). Two additional clades were only known from captivity (their wild range
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#173285605747011036-433: Is occasionally associated with hearing impairments. However, when tested, there was no differences in responses between wild-type and albinistic European wels catfish ( Silurus glanis ) and South American bronze catfish ( Corydoras aeneus ). Similarly, Mexican blind cave fish ( Astyanax mexicanus ) do not differ in hearing sensitivity from the normally pigmented and eyed surface-dwelling populations. Fish lack melanin in
11214-544: Is possible because of their metabolic reserves as well as their liver, which is capable of up regulating and down regulating certain proteins according to how long they have been fasting for. Both sexes maintain a territory , averaging 40 m (1,400 cu ft) for males and 30 m (1,100 cu ft) for females. The reproductive cycle is initiated when the water temperature reaches 20 °C (68 °F) and mating occurs between July and September. The female lays 400–500 eggs in an underwater breeding cavity, which
11392-450: Is restricted to the slightly cooler and wetter conditions in north-facing cove forests in the southern Appalachians, and to higher elevations above 900 m (3,000 ft), while the former is more adaptable, and would be perfectly able to inhabit these locations, but some unknown factor seems to prevent the two species from co-existing. One species, the Anderson's salamander , is one of
11570-758: Is the Latin for "tailed ones", from cauda : "tail". Salamander diversity is highest in eastern North America , especially in the Appalachian Mountains ; most species are found in the Holarctic realm , with some species present in the Neotropical realm . Salamanders never have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to
11748-598: Is unknown) and no samples are available for the population in the Tibetan Plateau . A 2019 study has identified that the Yangtze River clade comprises the "true" A. davidianus , the Pearl River clade comprises A. sligoi , and the Qiantang clade comprises the Huangshan Mountains species (described as A. cheni in 2023). A 2022 study identified one of the two clades known only from captivity as A. jiangxiensis , found in
11926-513: Is unknown, but it is at least 60 years based on captive individuals. Undocumented claims have been made of 200-year-old Chinese giant salamanders, but these are considered unreliable. The Chinese giant salamander species complex comprises five clades, with multiple possibly worthy of species recognition. Their native ranges differ, but release of Chinese giant salamanders from captivity has complicated this picture. They were widespread in central, south-western, and southern China, although their range
12104-413: Is used in courtship and as a storage organ for proteins and lipids. It also functions as a defense against predation, when it may be lashed at the attacker or autotomised when grabbed. Unlike frogs, an adult salamander is able to regenerate limbs and its tail when these are lost. The skin of salamanders, in common with other amphibians, is thin, permeable to water, serves as a respiratory membrane, and
12282-407: Is well-supplied with glands. It has highly cornified outer layers, renewed periodically through a skin shedding process controlled by hormones from the pituitary and thyroid glands. During moulting, the skin initially breaks around the mouth, and the animal moves forward through the gap to shed the skin. When the front limbs have been worked clear, a series of body ripples pushes the skin toward
12460-675: The Alaska Panhandle . They had an exclusively Laurasian distribution until Bolitoglossa invaded South America from Central America, probably by the start of the Early Miocene , about 23 million years ago. They also lived on the Caribbean Islands during the early Miocene epoch, confirmed by the discovery of Palaeoplethodon hispaniolae , found trapped in amber in the Dominican Republic . Vertebrae fossils recovered from
12638-641: The Chinese Red Book of Amphibians and Reptiles . Despite the Chinese Government listing the salamander as a Class II Protected Species, 100 salamanders are hunted illegally every year in the Hupingshan Natural Nature Reserve alone. Since the 1980s, 14 nature reserves have been established as an effort to conserve the species. Despite this, the population continues to decline with the salamanders becoming increasingly difficult to find. In
12816-900: The Holarctic and Neotropical regions, not reaching south of the Mediterranean Basin , the Himalayas , or in South America the Amazon Basin . They do not extend north of the Arctic tree line , with the northernmost Asian species, Salamandrella keyserlingii , which can survive long-term freezing at −55 °C, occurring in the Siberian larch forests of Sakha and the most northerly species in North America, Ambystoma laterale , reaching no farther north than Labrador and Taricha granulosa not beyond
12994-609: The Los Angeles Zoo . Additional individuals are likely kept in non- Species360 zoos and animals parks in its native China, such as Shanghai Zoo . Several of them are kept in the aquaria of Shanghai and Xi'an . The Osaka Aquarium Kaiyukan in Japan has both a Chinese and a Japanese giant salamander on display, as does the Saitama aquarium in Hanyū, Saitama . The Ueno Zoological Gardens also has
13172-600: The Murgon fossil site have been tentatively attributed to that of a Salamander, though its true identity is disputed. If the vertebrae truly belong to a Salamander, they would represent the only Salamanders in Australia . There are about 760 living species of salamander. One-third of the known salamander species are found in North America. The highest concentration of these is found in the Appalachian Mountains region, where
13350-449: The amphiumas , metamorphosis is incomplete, and they retain one pair of gill slits as adults, with fully functioning internal lungs. Some species that lack lungs respire through gills. In most cases, these are external gills, visible as tufts on either side of the head. Some terrestrial salamanders have lungs used in respiration, although these are simple and sac-like, unlike the more complex organs found in mammals . Many species, such as
13528-401: The cloud forests of Guatemala and Mexico during the 1970s were found by 2009 to be rare. Few data have been gathered on population sizes over the years and, by intensive surveying of historic and suitable new locations, it has been possible to locate individuals of other species, such as Parvimolge townsendi , which had been thought to be extinct . Currently, the major lines of defense for
13706-495: The family Salamandridae are mostly known as newts and lack the costal grooves along the sides of their bodies typical of other groups. The skin of some species contains the powerful poison tetrodotoxin ; these salamanders tend to be slow-moving and have bright warning coloration to advertise their toxicity. Salamanders typically lay eggs in water and have aquatic larvae, but great variation occurs in their lifecycles . Some species in harsh environments reproduce while still in
13884-586: The lens or retina of the eye. Within only a few weeks of losing a piece of a limb, a salamander perfectly reforms the missing structure. Salamanders split off from the other amphibians during the mid- to late Permian, and initially were similar to modern members of the Cryptobranchoidea . Their resemblance to lizards is the result of symplesiomorphy , their common retention of the primitive tetrapod body plan, but they are no more closely related to lizards than they are to mammals. Their nearest relatives are
14062-449: The neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour under white light: Animals can also appear coloured due to structural colour , the result of coherent scattering perceived as iridescence . The structures themselves are colourless. Light typically passes through multiple layers and is reflected more than once. The multiple reflections compound one another and intensify
14240-633: The olm , have both lungs and gills as adults. In the Necturus , external gills begin to form as a means of combating hypoxia in the egg as egg yolk is converted into metabolically active tissue. Molecular changes in the mudpuppy during post-embryonic development primarily due to the thyroid gland prevent the internalization of the external gills as seen in most salamanders that undergo metamorphosis. The external gills seen in salamanders differs greatly from that of amphibians with internalized gills. Unlike amphibians with internalized gills which typically rely on
14418-502: The ultraviolet range, based on three photoreceptor types that are maximally sensitive around 450, 500, and 570 nm. The larvae, and the adults of some highly aquatic species, also have a lateral line organ, similar to that of fish, which can detect changes in water pressure. All salamanders lack middle ear cavity, eardrum and eustachian tube , but have an opercularis system like frogs, and are still able to detect airborne sound. The opercularis system consists of two ossicles:
14596-464: The 20 species of minute salamanders ( Thorius spp.) in Mexico, half are believed to have become extinct and most of the others are critically endangered. Specific reasons for the decline may include climate change, chytridiomycosis, or volcanic activity, but the main threat is habitat destruction as logging, agricultural activities, and human settlement reduce their often tiny, fragmented ranges. Survey work
14774-515: The Albino Squirrel Preservation Society. They have also been protected in studies on their ecology, sociology and behaviour. Studies on medaka fish in the laboratory, i.e. with no predators, sufficient food supply, controlled temperatures, etc., found that albinos had considerably reduced viability; from 800 albino embryos, only 29 survived to full adulthood. Early studies on fish led some researchers to describe albinism as
14952-494: The California newt has many large poison glands in its skin, is diurnal, and is avoided by snakes. Some salamander species use tail autotomy to escape predators. The tail drops off and wriggles around for a while after an attack, and the salamander either runs away or stays still enough not to be noticed while the predator is distracted. The tail regrows with time, and salamanders routinely regenerate other complex tissues, including
15130-453: The Chinese giant salamander is ectothermic . Most Chinese giant salamanders stop feeding at water temperatures above 20 °C (68 °F) and feeding ceases almost entirely at 28 °C (82 °F). Temperatures of 35 °C (95 °F) are lethal to Chinese giant salamanders. As a consequence, the species is vulnerable to global warming . One of the main reasons that the Chinese giant salamander, Andrias davidianus , has been placed on
15308-548: The Convention of Endangered Species of Wild Fauna.). But the salamander populations have continued to decline. The domestic demand for salamander meat and body parts greatly exceeds what can sustainably be harvested from the wild. Commercial captive breeding operations so far still rely on the regular introduction of new wild-caught breeding adults, because captive-bred animals have proven difficult to mate. In addition, salamander farms would need to increase their yield manifold before
15486-510: The Plethodontidae are thought to have originated in mountain streams. Here, vegetation zones and proximity to water are of greater importance than altitude. Only species that adopted a more terrestrial mode of life have been able to disperse to other localities. The northern slimy salamander ( Plethodon glutinosus ) has a wide range and occupies a habitat similar to that of the southern gray-cheeked salamander ( Plethodon metcalfi ). The latter
15664-405: The animal of an approaching predator. Salamanders are usually considered to have no voice and do not use sound for communication in the way that frogs do. Before mating, they communicate by pheromone signaling; some species make quiet ticking, clicking, squeaks or popping noises, perhaps by the opening and closing of valves in the nose. Most salamanders lack vocal cords, but a larynx is present in
15842-422: The animal slippery and more difficult for predators to catch. Granular glands scattered on the upper surface, particularly the head, back, and tail, produce repellent or toxic secretions. Some salamander toxins are particularly potent. The rough-skinned newt ( Taricha granulosa ) produces the neurotoxin tetrodotoxin , the most toxic nonprotein substance known. Handling the newts does no harm, but ingestion of even
16020-404: The axolotl does not account for the overall lack of diversity. Evidence points toward a historical bottlenecking of Ambystoma that contributes to the variation issues and no longer a large genetic pool for it to pull from, thus raising concern for inbreeding due to lack of gene flow. One way researchers are looking into maintaining genetic diversity within the population is via cryopreservation of
16198-903: The banks. It is usually found in forested regions at altitudes of 100 to 1,500 m (300 to 4,900 ft), with most records between 300 and 800 m (1,000 and 2,600 ft). There is an isolated population at an altitude of 4,200 m (13,800 ft) in Qinghai (Tibetan Plateau), but its taxonomic position is uncertain and the site likely does not support giant salamanders anymore due to pollution. The salamanders prefer to live in streams of small width (on average, 6.39 m or 21 ft across), quick flow, and little depth (on average, 1.07 m or 3 ft 6 in deep). Water temperature varies depending on season, with typical range at low elevation sites being from 10 to 25 °C (50 to 77 °F) and at high elevation sites from 3 to 20 °C (37 to 68 °F). Although they prefer to have quick flow in
16376-484: The behaviour of albinos in the wild, e.g. leaping from branch to branch, is similar to pigmented squirrels. A 2012 survey of the literature reported that in India, there were several records of albino mammals including the tiger , lesser mouse-tailed bat , chital , common palm civet , northern palm squirrel , five-striped palm squirrel and wild boar . Albino macaques have been reported in several occasions including
16554-476: The best choice for scientific studies due to the consequences of albinism (e.g. hearing and visual impairments). Many individual albino mammals are in captivity and were caught while young. However, the survival prospects of these creatures into adulthood outside of captivity are uncertain. It is doubtful whether these individuals would have survived to become adults without the protection and care they receive in captivity. It has been claimed that "Squirrels are
16732-464: The black-market price of poached salamander drop significantly, meaning that a stricter enforcement of anti-poaching law is still very much the future for the Chinese giant salamander. China's penalty for illegally hunting these creatures is very low and only comes to 50 yuan , or about US$ 6, which is less than one hundred times the black-market price. Establishments such as restaurants can charge up to US$ 250–US$ 400 per kilogram. A hunting tool known as
16910-402: The body. Some aquatic species, such as sirens and amphiumas , have reduced or absent hind limbs, giving them an eel -like appearance, but in most species, the front and rear limbs are about the same length and project sideward, barely raising the trunk off the ground. The feet are broad with short digits, usually four on the front feet and five on the rear. Salamanders do not have claws, and
17088-424: The breeding season. Cave species dwelling in darkness lack pigmentation and have a translucent pink or pearlescent appearance. Salamanders range in size from the minute salamanders , with a total length of 27 mm ( 1 + 1 ⁄ 8 in), including the tail, to the Chinese giant salamander which reaches 1.8 m (6 ft) and weighs up to 65 kg (145 lb). All the largest species are found in
17266-413: The centre of the retina is under-developed and there is a deficit of rod cells, which detect light levels; the central ganglion cell density is approximately 25% below normal (except for the eastern gray squirrel ). In nearly all mammals, the overwhelming majority of photoreceptors are rods rather than cones, which detect color. Albinism specifically affects the rod cells, but the number and distribution of
17444-455: The changing of pressures within the buccal and pharyngeal cavities to ensure diffusion of oxygen onto the gill curtain, neotenic salamanders such as Necturus use specified musculature, such as the levatores arcuum, to move external gills to keep the respiratory surfaces constantly in contact with new oxygenated water. Salamanders are opportunistic predators . They are generally not restricted to specific foods, but feed on almost any organism of
17622-452: The chin which are pressed against the females' nostrils during the courtship ritual. They may function to speed up the mating process, reducing the risk of its being disrupted by a predator or rival male. The gland at the base of the tail in Plethodon cinereus is used to mark fecal pellets to proclaim territorial ownership. Olfaction in salamanders plays a role in territory maintenance,
17800-468: The cloacae of females. The results of this research may be used in captive-breeding programmes for endangered species. The order name Urodela comes from the name Urodèles given by André Marie Constant Duméril in 1805, it is derived from the Greek words οὐρά ourā́ "tail" and δῆλος dēlos "visible, conspicuous" because of their "persistent" tails. Disagreement exists among different authorities as to
17978-416: The colours. Structural colour differs according to the observer's position whereas pigments appear the same regardless of the angle-of-view. Animals that show iridescence include mother of pearl seashells, fish, and peacocks. These are just a few examples of animals with this quality, but it is most pronounced in the butterfly family. The primary function of pigments in plants is photosynthesis , which uses
18156-424: The columella (equivalent to the stapes of higher vertebrates ) which is fused to the skull, and the operculum. An opercularis muscle connects the latter to the pectoral girdle, and is kept under tension when the animal is alert. The system seems able to detect low-frequency vibrations (500–600 Hz), which may be picked up from the ground by the fore limbs and transmitted to the inner ear. These may serve to warn
18334-422: The condition are referred to as albinos . Varied use and interpretation of the terms mean that written reports of albinistic animals can be difficult to verify. Albinism can reduce the survivability of an animal; for example, it has been suggested that albino alligators have an average survival span of only 24 hours due to the lack of protection from UV radiation and their lack of camouflage to avoid predators. It
18512-407: The cones is unaffected. In contrast, the retinas of birds are cone rich, meaning that the vision of albino birds is affected less than albino mammals. Melanin protects the skin from ultra-violet radiation in sunlight. Melanosomes block harmful electromagnetic radiation from the sun while allowing beneficial frequencies to enter the body. This means some animals may die from UV radiation due to
18690-608: The conservation of Salamanders includes both in situ and ex situ conservation methods. There are efforts in place for certain members of the Salamander family to be conserved under a conservation breeding program (CBP) but there should be research done ahead of time to determine if the Salamander species is actually going to value from the CBP, as researchers have noted that some species of amphibians completely fail in this environment. Various conservation initiatives are being attempted around
18868-498: The control of thyroid hormones and in obligate neotenes such as the axolotl ( Ambystoma mexicanum ), the tissues are seemingly unresponsive to the hormones. In other species, the changes may not be triggered because of underactivity of the hypothalamus-pituitary-thyroid mechanism which may occur when conditions in the terrestrial environment are too inhospitable. This may be due to cold or wildly fluctuating temperatures, aridity, lack of food, lack of cover, or insufficient iodine for
19046-690: The costs, some individuals do reach adult age and breeding status. Albino dolphins were first sighted in the Gulf of Mexico in 1962. Since 1994, three further individuals have been seen. These tend to be pink in colour due to blood vessels showing through the blubber and unpigmented skin. A report published in 2008 stated that in marine mammals, "anomalously white" individuals have been reported for 21 cetacean species and seven pinniped species but there were no known reports of anomalously white sea otters ( Enhydra lutris ) or sirenians . Whales and dolphins also may appear white if extensively scarred, or covered with
19224-460: The critically endangered list by the International Union for Conservation of Nature is overhunting. 75% of native species in China are harvested for food. The salamander is also used for traditional medicinal purposes. In 1989, the Chinese government placed legal protection on the salamander (category II due to its population decline by The Wild Animal Protection Law of China and Appendix I in
19402-896: The definition of albinism precludes the possibility of "partial albinism" in which a mostly white bird shows some form of melanin pigmentation. "It is simply impossible, just like being 'partially pregnant'. As with other animals, it has been stated that for fish to be properly described as "albino", they must have a white body and pink or red eyes. Zebrafish have three types of chromatophores—iridophores, melanophores, and xanthophores—which produce silver, black, and yellow pigmentation respectively. Zebrafish that lack iridophores are known as roy mutants , those that lack melanophores as albino mutants , and those which lack both melanophores and iridophores are ruby mutants . The gross eye morphology, feeding and swimming behaviours between wild-type and albino zebrafish were indistinguishable, except under dim or bright light or low contrast. In mammals, albinism
19580-650: The definition of the terms Caudata and Urodela. Some maintain that the Urodela should be restricted to the crown group , with the Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article. Albinism in biology Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. Individuals with
19758-407: The degradation of their habitats by soiling the water. Deforestation in areas near the streams can worsen soil erosion and create runoff into the streams as well, which reduces the water quality to a great extent. The reduced water quality makes it much more difficult for the salamanders to absorb oxygen through their skin and can often bring death to those within the species. Water pollution
19936-603: The different species of salamanders, and can involve gills, lungs, skin, and the membranes of mouth and throat. Larval salamanders breathe primarily by means of gills , which are usually external and feathery in appearance. Water is drawn in through the mouth and flows out through the gill slits. Some neotenic species such as the mudpuppy ( Necturus maculosus ) retain their gills throughout their lives, but most species lose them at metamorphosis . The embryos of some terrestrial lungless salamanders, such as Ensatina , that undergo direct development, have large gills that lie close to
20114-406: The egg's surface. When present in adult salamanders, lungs vary greatly among different species in size and structure. In aquatic, cold-water species like the torrent salamanders ( Rhyacotriton ), the lungs are very small with smooth walls, while species living in warm water with little dissolved oxygen, such as the lesser siren ( Siren intermedia ), have large lungs with convoluted surfaces. In
20292-750: The eggs are laid. In the Asiatic salamanders , the giant salamanders and Sirenidae , which are the most primitive groups, the fertilization is external. In a reproductive process similar to that of typical frogs, the male releases sperm onto the egg mass. These salamanders also have males that exhibit parental care , which otherwise only occur in females with internal fertilization. Three different types of egg deposition occur. Ambystoma and Taricha spp. spawn large numbers of small eggs in quiet ponds where many large predators are unlikely. Most dusky salamanders ( Desmognathus ) and Pacific giant salamanders ( Dicamptodon ) lay smaller batches of medium-sized eggs in
20470-437: The eggs inside her body until they hatch, either into larvae to be deposited in a water body, or into fully formed juveniles. In temperate regions, reproduction is usually seasonal and salamanders may migrate to breeding grounds. Males usually arrive first and in some instances set up territories . Typically, a larval stage follows in which the organism is fully aquatic. The tadpole has three pairs of external gills, no eyelids,
20648-575: The entire countrywide wild population estimated at less than 50,000 individuals. Shaanxi farms (mainly in the Qinling Mountain region) accounted for about 70% of the total output in China in 2012, but there are also many farms in Guizhou and several in other provinces. Among 43 south Shaanxi farms surveyed, 38 bred the species in 2010 and each produced an average of c. 10,300 larvae that year. Farming of Chinese giant salamanders, herbs , and mushrooms are
20826-530: The few species of living amphibians to occur in brackish or salt water. Many salamanders do not use vocalisations, and in most species the sexes look alike, so they use olfactory and tactile cues to identify potential mates, and sexual selection occurs. Pheromones play an important part in the process and may be produced by the abdominal gland in males and by the cloacal glands and skin in both sexes. Males are sometimes to be seen investigating potential mates with their snouts. In Old World newts, Triturus spp.,
21004-481: The formation of thyroid hormones. Genetics may also play a part. The larvae of tiger salamanders ( Ambystoma tigrinum ), for example, develop limbs soon after hatching and in seasonal pools promptly undergo metamorphosis. Other larvae, especially in permanent pools and warmer climates, may not undergo metamorphosis until fully adult in size. Other populations in colder climates may not metamorphose at all, and become sexually mature while in their larval forms. Neoteny allows
21182-406: The four families giant salamanders , sirens , Congo eels and Proteidae , who are all aquatic and obligate paedomorphs. Some of the largest terrestrial salamanders, which goes through full metamorphosis, belongs to the family of Pacific giant salamanders , and are much smaller. Most salamanders are between 10 and 20 cm (4 and 8 in) in length. An adult salamander generally resembles
21360-680: The frogs and toads, within Batrachia . The oldest known total-group ( Caudata ) salamander is Triassurus from the Triassic of Kyrgyzstan . Further salamander fossils are known from the Middle Jurassic of England , Scotland , China , and Kazakhstan . The oldest known crown-group salamander ( Urodela ) remains uncertain but recent analyses suggest it is Valdotriton from the Late Jurassic of Spain . Salamanders are found only in
21538-449: The future. Skin secretions of the tiger salamander ( Ambystoma tigrinum ) fed to rats have been shown to produce aversion to the flavor, and the rats avoided the presentational medium when it was offered to them again. The fire salamander ( Salamandra salamandra ) has a ridge of large granular glands down its spine which are able to squirt a fine jet of toxic fluid at its attacker. By angling its body appropriately, it can accurately direct
21716-505: The genus, the Chinese Andrias species introduced to Japan and hybridizing with A. japonicus is the "true" A. davidianus (the Yangtze River clade, or lineage B), although at least one genetically pure individual of the captive-only lineage U1 was also detected in the wild. The Chinese giant salamander is entirely aquatic and lives in rocky hill streams and lakes with clear water. It typically lives in dark, muddy, or rocky crevices along
21894-632: The government (8,000 were released in Shaanxi in 2011 alone), but represent a potential risk to the remaining wild population, as diseases such as Ranavirus are known from many farms. The vast majority of the farmed Chinese giant salamanders, almost 80% based on a study published in 2018, are of Yellow River origin (the so-called haplotype B), although those from other regions also occur. Farms have generally not considered this issue when releasing giant salamanders and Yellow River animals now dominate in some regions outside their original range, further endangering
22072-590: The green pigment chlorophyll along with several red and yellow pigments including porphyrins , carotenoids , anthocyanins and betalains . Definitions of albinism vary and are inconsistent. While they are clear and precise for humans and other mammals, this is because the majority of mammals have only one pigment, melanin. Many animals have pigments other than melanin, and some also have structural colours. Some definitions of albinism, whilst taking most taxa into account, ignore others. So, "a person or animal with very pale skin, white hair or fur, and pink eyes caused by
22250-437: The ground or in the water according to species, and the female picks this up with her vent. The spermatophore has a packet of sperm supported on a conical gelatinous base, and often an elaborate courtship behavior is involved in its deposition and collection. Once inside the cloaca, the spermatozoa move to the spermatheca , one or more chambers in the roof of the cloaca, where they are stored for sometimes lengthy periods until
22428-403: The larvae of salamanders possess these teeth. Although larval teeth are shaped like pointed cones, the teeth of adults are adapted to enable them to readily grasp prey. The crown , which has two cusps (bicuspid), is attached to a pedicel by collagenous fibers. The joint formed between the bicuspid and the pedicel is partially flexible, as it can bend inward, but not outward. When struggling prey
22606-404: The larval stage may last from days to years, depending on species. Sometimes this stage is completely bypassed, and the eggs of most lungless salamanders (Plethodontidae) develop directly into miniature versions of the adult without an intervening larval stage. By the end of the larval stage, the tadpoles already have limbs and metamorphosis takes place normally. In salamanders, this occurs over
22784-612: The larval state. The word salamander comes from Old French salamandre from Latin salamandra from Greek σαλαμάνδρα : salamándra, of uncertain, possibly, pre-Greek origin. The Greek word is used for the fire salamander . The skin lacks scales and is moist and smooth to the touch, except in newts of the Salamandridae, which may have velvety or warty skin, wet to the touch. The skin may be drab or brightly colored, exhibiting various patterns of stripes, bars, spots, blotches, or dots. Male newts become dramatically colored during
22962-804: The last few decades of the 20th century, although no direct link between the fungus and the population decline has yet been found. The IUCN made further efforts in 2005 as they established the Amphibian Conservation Action Plan (ACAP), which was subsequently followed by Amphibian Ark (AArk), Amphibian Specialist Group (ASG), and finally the umbrella organization known as the Amphibian Survival Alliance (ASA). Researchers also cite deforestation , resulting in fragmentation of suitable habitats, and climate change as possible contributory factors. Species such as Pseudoeurycea brunnata and Pseudoeurycea goebeli that had been abundant in
23140-727: The local population on the restoration of the natural habitat of these creatures. This proximity is a large factor that has impacted the survival of the axolotl, as the city has expanded to take over the Xochimilco region in order to make use of its resources for water and provision and sewage. It is farmed for use in research facilities and so may one day return to its natural habitat. The recent decline in population has substantially impacted genetic diversity among populations, making it difficult to further progress scientifically. Some genetic indiversity due to paedeomorphism in Ambystoma species such as
23318-410: The lungless salamanders ( family Plethodontidae and the clawed salamanders in the family of Asiatic salamanders ), no lungs or gills are present, and gas exchange mostly takes place through the skin, known as cutaneous respiration , supplemented by the tissues lining the mouth. To facilitate this, these salamanders have a dense network of blood vessels just under the skin and in the mouth. In
23496-471: The males are sexually dimorphic and display in front of the females. Visual cues are also thought to be important in some Plethodont species. Except for terrestrial species in the three families Plethodontidae , Ambystomatidae , and Salamandridae , salamanders mate in water. The mating varies from courtship between a single male and female to explosive group breeding. In the clade Salamandroidea , which makes up about 90% of all species, fertilization
23674-521: The males compared to the wild-type; albino males had higher mount frequencies than wild-type males. In addition, the albinos had greater differential fertilizing capacity. Albinism can also occur in marsupials and monotremes , such as echidnas , kangaroos , koalas , possums , wallabies and wombats . The costs of albinism for marine mammals may include reduced heat absorption in colder waters, poor camouflage from predators, increased sensitivity to sunlight, and impaired visual communication. Despite
23852-510: The mudpuppy (Necturus) and some other species, and the Pacific giant salamanders and a few others have a large larynx and bands known as plicae vocales. The California giant salamander can produce a bark or rattle, and a few species can squeak by contracting muscles in the throat. The arboreal salamander can squeak using a different mechanism; it retracts its eyes into its head, forcing air out of its mouth. The ensatina salamander occasionally makes
24030-587: The native types. Additionally, release of untreated wastewater from farms may spread diseases to wild Chinese giant salamanders. As of early 2008, Species360 records show only five individuals held in US zoos ( Zoo Atlanta , Cincinnati Zoo , and Saint Louis Zoological Park ), and an additional four in European zoos ( Dresden Zoo and Rotterdam Zoo ); as well as one in the State Museum of Natural History Karlsruhe, where it
24208-613: The normal development of various parts of the eye, including the iris, retina, eye muscles, and optic nerve. The absence of melanin results in abnormal development of eyes and leads to problems with focusing, and depth perception. The eyes of albino animals appear red because the colour of the red blood cells in the retina can be seen through the iris, which has no pigment to obscure this. Some albino animals may have pale-blue eyes due to other colour generating processes. Albino vertebrates exposed to intense light typically lose photoreceptors due to apoptosis . In all albino mammals studied,
24386-425: The only known albino mammal to survive successfully in the wild". The retina of the squirrel ( Sciurus carolinensis ) is unusual for mammals as it is rich in cones. Central cell densities are less than 5% lower in albino squirrels than in pigmented individuals. This relatively minor disruption to vision is thought to assist in the survivability of albino squirrels in the wild. This is supported by observations that
24564-438: The other clades. It has a large head, small eyes and dark wrinkly skin. Its flat, broad head has a wide mouth, round, lidless eyes, and a line of paired tubercles that run around its head and throat. Its color is typically dark brown with a mottled or speckled pattern, but it can also be other brownish tones, dark reddish, or black. Albinos , which are white or orange, have been recorded. All species of giant salamanders produce
24742-537: The palatable yellow-eyed salamander ( Ensatina eschscholtzii ) closely resembles the toxic California newt ( Taricha torosa ) and the rough-skinned newt ( Taricha granulosa ), whereas in other parts of its range, it is cryptically colored. A correlation exists between the toxicity of Californian salamander species and diurnal habits: relatively harmless species like the California slender salamander ( Batrachoseps attenuatus ) are nocturnal and are eaten by snakes, while
24920-517: The prey to shoot back into their mouths as well as a copious amount of water. They then close their mouths, but leave a small gap between their upper and lower lips so that the captured water can escape. The Chinese giant salamander catches its prey on land with an asymmetrical bite, in such a way that the force created by their jaws will be maximized in the anterior region where their prey is located. After capture they use their bite to subdue and kill their prey, both on land and in water. They are missing
25098-579: The prey, which is then swallowed. Though frequently feeding on slow-moving animals like snails , shrimps and worms , sirenids are unique among salamanders for having developed herbivory speciations, such as beak-like jaw ends and extensive intestines. They feed on algae and other soft-plants in the wild, and easily eat offered lettuce . Salamanders have thin skins and soft bodies, move rather slowly and might appear vulnerable to opportunistic predation, but have several effective lines of defense. Mucus coating on damp skin makes them difficult to grasp, and
25276-403: The rate is once in every 1,764 births. Some species, such as white peacocks, swans and geese, are not believed to be true albinos, as they do not have red eyes, rather, their colouration is suggested to be the expression of a white fur or feather gene, not a lack of melanin. Melanin has several functions in most mammals and other animals; these are disrupted by albinism. Melanin functions in
25454-488: The rear. The hind limbs are extracted and push the skin farther back, before it is eventually freed by friction as the salamander moves forward with the tail pressed against the ground. The animal often then eats the resulting sloughed skin. Glands in the skin discharge mucus which keeps the skin moist, an important factor in skin respiration and thermoregulation. The sticky layer helps protect against bacterial infections and molds, reduces friction when swimming, and makes
25632-410: The recognition of predators, and courtship rituals, but is probably secondary to sight during prey selection and feeding. Salamanders have two types of sensory areas that respond to the chemistry of the environment. Olfactory epithelium in the nasal cavity picks up airborne and aquatic odors, while adjoining vomeronasal organs detect nonvolatile chemical cues, such as tastes in the mouth. In plethodonts,
25810-480: The salamander family. Research is being done on the environmental cues that have to be replicated before captive animals can be persuaded to breed. Common species such as the tiger salamander and the mudpuppy are being given hormones to stimulate the production of sperm and eggs, and the role of arginine vasotocin in courtship behaviour is being investigated. Another line of research is artificial insemination , either in vitro or by inserting spermatophores into
25988-559: The same rate. Furthermore, in certain species, albino animals may be excluded from families or other groups, or rejected as mates. On the other hand, there is also evidence for positive selection for albinism in some animals, as well as cultural selection favoring albino people in some human societies, which results in the increase of genes associated with albinism. The founder effect may explain why some animal populations become selected for albinism. The novelty of albino animals has occasionally led to their protection by groups such as
26166-448: The sensory epithelium of the vomeronasal organs extends to the nasolabial grooves , which stretch from the nostrils to the corners of the mouth. These extended areas seem to be associated with the identification of prey items, the recognition of conspecifics , and the identification of individuals. The eyes of most salamanders are adapted primarily for vision at night. In some permanently aquatic species, they are reduced in size and have
26344-600: The seven types of oculocutaneous albinism that have been identified in humans (and confirmed in some other animals) and the use of the term "partial albino" is therefore misleading. One definition states that "albinism, (from the Latin albus, meaning "white"), hereditary condition characterized by the absence of pigment in the eyes, skin, hair, scales, or feathers", however, this does not encompass invertebrates, nor does it include plants. Furthermore, it could be interpreted that "...absence of pigment..." does not include an absence of structural colours. The lack of clarity about
26522-413: The several other pigments that non-mammalian animals have and also structural colouration. For example, "Absence of the pigment melanin in the eyes, skin, hair, scales, or feathers." refers only to the pigment melanin. Because of the various uses of different terms applied to colouration, some authors have indicated that the colour of the eyes is the defining characteristic of albinism, e.g. "This leads to
26700-462: The shape of the foot varies according to the animal's habitat. Climbing species have elongated, square-tipped toes, while rock-dwellers have larger feet with short, blunt toes. The tree-climbing salamander ( Bolitoglossa sp.) has plate-like webbed feet which adhere to smooth surfaces by suction, while the rock-climbing Hydromantes species from California have feet with fleshy webs and short digits and use their tails as an extra limb. When ascending,
26878-420: The skin and eyes, only eumelanin is present. In some bird species, the colour is completely caused by eumelanin, however, both types of melanin are found in most species. In birds, albinism has been defined as "a total lack of both melanins in feathers, eyes and skin as a result of an inherited absence of tyrosinase", however, this ignores the effects of other pigments and structural colours. An albino bird has
27056-529: The slightly larger South China giant salamander ( A. sligoi ), the Jiangxi giant salamander ( Andrias jiangxiensis ), the Qimen giant salamander ( Andrias cheni ), and the far smaller North American hellbender ( Cryptobranchus alleganiensis ). A 2018 study of mitochondrial DNA revealed that there are five wild clades of the Chinese giant salamander, as well as two only known from captives (their possible wild range
27234-429: The slimy coating may have an offensive taste or be toxic. When attacked by a predator, a salamander may position itself to make the main poison glands face the aggressor. Often, these are on the tail, which may be waggled or turned up and arched over the animal's back. The sacrifice of the tail may be a worthwhile strategy, if the salamander escapes with its life and the predator learns to avoid that species of salamander in
27412-549: The soil that come with it—has a vastly negative effect on the areas near the streams as well. The presence of macronutrients in the streams can also cause algal blooms , which cloud the water and force the temperature to rise. The salamanders reside primarily in very cold underwater cavities and follow a specific nesting requirement, which means that they will only reproduce and care for their eggs in areas such as these, so changes in temperature are incredibly detrimental to their health and well-being as well as to their perpetuation as
27590-454: The species to survive even when the terrestrial environment is too harsh for the adults to thrive on land. A general decline in living amphibian species has been linked with the fungal disease chytridiomycosis . A higher proportion of salamander species than of frogs or caecilians are in one of the at-risk categories established by the IUCN . Salamanders showed a significant diminution in numbers in
27768-432: The spermatophores from the male axolotl. It is a safe and non-invasive method that requires the collection of the spermatophores and places them into a deep freeze for preservation. Most importantly, they have found that there is only limited damage done to the spermatophores upon thawing and thus it is a viable option. As of 2013, it is a method that is being used to save not only the axolotl but also numerous other members of
27946-439: The spray for a distance of up to 80 cm (30 in). The Iberian ribbed newt ( Pleurodeles waltl ) has another method of deterring aggressors. Its skin exudes a poisonous, viscous fluid and at the same time, the newt rotates its sharply pointed ribs through an angle between 27 and 92°, and adopts an inflated posture. This action causes the ribs to puncture the body wall, each rib protruding through an orange wart arranged in
28124-460: The stomach. The outer most layer has ciliated cells that move mucous from mucous glands over the surface of the esophagus to lubricate it and reduce friction from large foods such as whole crabs. The ciliated structure and flexibility of the Chinese giant salamander's esophagus is hypothesized to be the reason why it is capable of swallowing such large foods. Chinese giant salamanders are also capable of fasting for several years if they need to. This
28302-415: The stream, the burrows in which they lay their eggs often have much slower flow. Furthermore, their habitat often possesses very rocky, irregular stream beds with a lot of gravel and small rocks as well as some vegetation. Chinese giant salamanders are also known from subterranean rivers . As populations in aboveground rivers and lakes are more vulnerable to poaching , there are some parts of China where only
28480-552: The study supporting its revival as a distinct taxon. Another then-undescribed species was also identified that formerly inhabited rivers originating from the Huangshan mountains in eastern China; this was described as Andrias cheni in 2023. In 2022, one of the captive-only clades was described as Andrias jiangxiensis , and was found to have maintained genetically pure wild populations in Jiangxi Province , in contrast to most of
28658-516: The subterranean populations remain. Very large numbers are being farmed in China, but most of the breeding stock are either wild-caught or first-generation captive-bred. This is partially explained by the fact that the industry is relatively new, but some farms have also struggled to produce second-generation captive-bred offspring. Registrations showed that 2.6 million Chinese giant salamanders were kept in farms in 2011 in Shaanxi alone, far surpassing
28836-478: The surveys had been performed in provinces that were only selected by habitat suitability modeling and had no actual historic records of giant salamanders. Based on this, the extent of extirpation of Chinese Andrias remains uncertain, especially as a natural population of Andrias jiangxiensis was discovered during the Chai et al. study. Salamander Cryptobranchoidea Salamandroidea Salamanders are
29014-406: The tail props up the rear of the body, while one hind foot moves forward and then swings to the other side to provide support as the other hind foot advances. In larvae and aquatic salamanders, the tail is laterally flattened, has dorsal and ventral fins, and undulates from side to side to propel the animal through the water. In the families Ambystomatidae and Salamandridae, the male's tail, which
29192-594: The term is furthered when the name of an animal includes the term "albino" although the animals (clearly) do not have the condition. For example, the albino gaur has this name because it is ash-grey whereas other gaur are almost black. A clear definition appears to be – "Congenital absence of any pigmentation or colouration in a person, animal, or plant, resulting in white hair and pink eyes in mammals." Whilst this does not state specifically that non-mammalian albino animals (or plants) are white, this can be inferred from "...absence of any pigmentation or colouration..." Due to
29370-401: The three most important economic activities in Shaanxi's Qinling Mountain region, and many thousands of families rely on the giant salamander farms for income. The giant salamander farming mainly supplies the food market, but whether this can be achieved to an extent where the pressure on the wild populations is reduced is doubtful. Release of captive-bred Chinese giant salamanders is supported by
29548-413: The throat, assisted by depression of the eyeballs into the roof of the mouth. Many lungless salamanders of the family Plethodontidae have more elaborate feeding methods. Muscles surrounding the hyoid bone contract to store elastic energy in springy connective tissue, and actually "shoot" the hyoid bone out of the mouth, thus elongating the tongue. Muscles that originate in the pelvic region and insert in
29726-431: The tongue are used to reel the tongue and the hyoid back to their original positions. An aquatic salamander lacks muscles in the tongue, and captures its prey in an entirely different manner. It grabs the food item, grasps it with its teeth, and adopts a kind of inertial feeding. This involves tossing its head about, drawing water sharply in and out of its mouth, and snapping its jaws, all of which tend to tear and macerate
29904-487: The tongue bulges and changes shape as it shoots forward. The protruded tongue has a central depression, and the rim of this collapses inward as the target is struck, trapping the prey in a mucus-laden trough. Here it is held while the animal's neck is flexed, the tongue retracted and jaws closed. Large or resistant prey is retained by the teeth while repeated protrusions and retractions of the tongue draw it in. Swallowing involves alternate contraction and relaxation of muscles in
30082-521: The varied use and interpretation of the term "albino", written reports of albinistic organisms can often not be verified. Melanin is an organic pigment that produces most of the colour seen in mammals. Depending on how it is created, melanin comes in two colour ranges, eumelanin (producing dark browns and blacks) and pheomelanin (producing light reddish tans and blondes). The dark and light melanins have their influence either alone or in conjunction, making either plain or multi-coloured coats. Sometimes, in
30260-455: The water intermittently, and others are entirely terrestrial as adults. This group of amphibians is capable of regenerating lost limbs as well as other damaged parts of their bodies. Researchers hope to reverse engineer the regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or preventing harmful scarring during heart surgery recovery. The remarkable ability of salamanders to regenerate
30438-508: The wild only in Jiangxi Province . Finds in Taiwan may be the result of introduction , though their exact taxonomic identity is unknown. Chinese giant salamanders have been introduced to the Kyoto Prefecture in Japan where they present a threat to the native Japanese giant salamander , as the two hybridize. A 2024 genetic study confirmed that in spite of the recent taxonomic changes within
30616-465: The wild populations studied were found "critically depleted or extirpated" by the study. A related study found that some of the five distinct genetic lineages were probably already extinct in the wild. However, the exhaustiveness of these surveys was questioned in a 2022 study by Chai et al ., who noted that over a third of the surveys had been performed only in Guizhou Province , and another third of
30794-423: The wild, e.g., Mexican cave tetra . Albinism is a well-recognized phenomenon in molluscs, both in the shell and in the soft parts. It has been claimed by some that albinism can occur for a number of reasons aside from inheritance, including genetic mutations, diet, living conditions, age, disease, or injury. However, this is contrary to definitions where the condition is inherited. Oculocutaneous albinism (OCA)
30972-473: The world. The Chinese giant salamander , at 1.8 m (6 ft) the largest amphibian in the world, is critically endangered , as it is collected for food and for use in traditional Chinese medicine . An environmental education programme is being undertaken to encourage sustainable management of wild populations in the Qinling Mountains and captive breeding programmes have been set up. The hellbender
31150-428: Was destroyed by the year 2000, and there are many human-related causes of such massive destruction. Because the salamander dwells in free-flowing streams, industrialization is a large problem for many stream-dwelling species. The construction of dams greatly disturbs their habitat by either causing these streams to dry up or to stand still, thus making it uninhabitable by the salamanders. Siltation also contributes to
31328-451: Was named the Chinese giant salamander iridovirus (GSIV). Its natural range has suffered in the past few decades due to habitat loss and overharvesting . Consequently, many salamanders are now farmed in mesocosms across China. Furthermore, previously built concrete dams that destroyed the salamander's habitat are now fitted with stairs so that the animal can easily navigate the dam and make it back to its niche. The Chinese giant salamander
31506-524: Was observed from the Polooni area in Malappuram district and Chaliyam area of Calicut district (Kerala). As albinism is observed in those areas where the density of these mammals is comparatively low, it is concluded that continuous inbreeding could be the reason for expression of albinism. A study on albinistic prairie voles ( Microtus ochrogaster ) found that albinism in this species conferred an advantage for
31684-476: Was previously unknown). They diverged from each other 4.71–10.25 million years ago and should possibly be recognized as cryptic species . Despite this deep divergence, they can hybridize among each other, and also with the Japanese giant salamander. One of these clades was identified in 2019 as Andrias sligoi , a species described in 1924 by Edward George Boulenger and later synonymized with A. davidianus , with
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