Andrias davidianus

Geographic Range

Habitat

Chinese giant salamanders spawn in freshwater cavities or caves that are protected by an adult male. After hatching, larvae move into the streams to which these caves and cavities are connected. They spend the rest of their lives in those streams and rivers and occasionally move into larger lakes. These bodies of waters are fast-running with a large amount of bank-side vegetation and are found in temperate mountainous regions. Chinese giant salamanders are usually found in elevations between 300 and 800 m, but they can be found in streams 190 to 1,330 m high. These waters are, on average, 1.07 m deep. (Chen, et al., 2018; Liang, et al., 2004; Sparreboom and Chang, 2019)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • Other Habitat Features
  • caves
  • Range elevation
    300 to 800 m
    984.25 to 2624.67 ft
  • Average depth
    1.07 m
    3.51 ft

Physical Description

Chinese giant salamanders are the largest living member of the class Amphibia. They average 1 m in length and weigh approximately 11 kg, though individuals as long as 1.8 m have been found in the past. Their bodies are heavily built and flat, with short limbs, a dorsal fin running from their bodies to their tails, and large compressed tails that make up 59% of their total body length. Their heads are flat and have two small, rounded, lidless eyes and large arched mouths. Like all members of the class Amphibia, Chinese giant salamanders have vomerine teeth. Their skin is rough and porous and can be dark brown, green, or black in color. Irregular marbled markings are found on the skin. Larvae resemble adult individuals in shape. There is no geographic or seasonal variation reported. (Nickerson, 2004; Sparreboom and Chang, 2019)

There is little sexual dimorphism in Chinese giant salamanders. Slight dimorphism is only seen around mating season, when the cloacal glands of adult males exhibit enlarged swelling. (Nickerson, 2004)

  • Sexual Dimorphism
  • sexes shaped differently
  • Average mass
    11 kg
    24.23 lb
  • Average length
    1 m
    3.28 ft

Development

Chinese giant salamanders grow continuously throughout their lives and exhibit three stages: egg, larval, and adult. Eggs hatch 40 to 60 days after fertilization. Tadpoles are 3.5 cm long with developed branchia. A month after hatching, they have fully developed forelimbs and posterior limbs. Toe differentiation in the limbs develops gradually. Lungs start to develop and after eight months, branchia start to degenerate and metamorphosis begins. One or two years after branchial degeneration begins, their branchia are completely gone and they are completely reliant upon their lungs.

Metamorphosis ends when Chinese giant salamanders are around 2.5 or 3 years old. They reach maturity and enter adulthood at approximately 5 or 6 years of age and 40 to 50 cm in length. Chinese giant salamanders exhibit indeterminate growth. This means once they reach maturity, they continue growing at a set pace. (Browne, et al., 2014; Jian, et al., 2007; Nickerson, 2004)

Reproduction

Chinese giant salamanders breed yearly. They are usually monogamous, but males have been observed to mate with more than one female in a single breeding season. Males enter individual dens in August. These dens are usually pre-existing aquatic caves or cavities.

Males engage in a behavior called 'sand-pushing' where they push sand and gravel out of their dens. Sand-pushing can last for 8 days and, once completed, their dens are smooth and clean. Clean dens attract females. Males also 'shower' themselves. They leave their dens and rinse their bodies, which promotes testis development and initiates courtship.

Courtship, which occurs about one month before eggs are laid, is made up of eight behaviors: knocking bellies, side-by-side behavior, cohabitating, riding, mouth-to-mouth posturing, chasing, inviting, and rolling over. Cohabitating - where males and females live in the same den - occurs about 88.32% of the time and is the mating behavior used most frequently. After courtship occurs and Chinese giant salamanders have found ideal partners, oviposition is accomplished. Males fertilize eggs produced by females. (Browne, et al., 2014; Luo, et al., 2018; Nickerson, 2004)

The breeding season for Chinese giant salamanders spans from August to September. After mating, females lay their eggs in an underwater cavity or cave, which is protected by their male mate. Females lays 300 to 560 eggs that are 7 to 8 mm in diameter. After fertilization, male salamanders protect and care for the eggs. After hatching, larvae develop in the streams that they will reside in once they reach adulthood. (Browne, et al., 2014; Luo, et al., 2018)

  • Breeding interval
    Chinese giant salamanders breed once yearly.
  • Breeding season
    The breeding season for Chinese giant salamanders is in August and September.
  • Range number of offspring
    300 to 560
  • Average number of offspring
    350
  • Range time to hatching
    40 to 60 days
  • Average time to independence
    1 days
  • Range age at sexual or reproductive maturity (female)
    5 to 7 years
  • Range age at sexual or reproductive maturity (male)
    5 to 7 years

Parental care observed in Chinese giant salamanders takes place during pre-hatching. Once eggs are hatched, larvae are independent of their parents. During the pre-hatching phase, fathers protects their eggs and the den in which they are laid. Males are referred to as den masters.

Fathers observe their eggs to make sure they develop correctly. They do this by tail-fanning, agitating the eggs, shaking, and egg eating. Tail-fanning is the dominant behavior and is done to increase the water flow and amount of dissolved oxygen in the water, which is needed for proper embryonic development. Agitating eggs accomplishes the same goal. Shaking, which is when fathers shake the trunks of their bodies, prevents the eggs from becoming infected by water mold and prevents yolks from sticking to the shells. Males eat unfertilized, yolk-stuck, and water-mold-infected eggs. This is done to reduce the potential for contamination of healthy eggs. Female individuals have not been observed to participate in parental care. (Luo, et al., 2018)

  • Parental Investment
  • male parental care
  • pre-hatching/birth
    • provisioning
      • male
    • protecting
      • male

Lifespan/Longevity

The maximum lifespan of Chinese giant salamanders is unknown. However, based on specimens in captivity, they can live for at least 60 years. The other extant species in the same genus, Japanese giant salamanders (Andrias japonicus), have a maximum lifespan of 72 years. (Browne, et al., 2014)

  • Average lifespan
    Status: wild
    60 years
  • Average lifespan
    Status: captivity
    60 years

Behavior

Little is known about the behavior of Chinese giant salamanders. They are primarily nocturnal animals and are extremely territorial. They are most active during the mid-evening. This behavior of territoriality increases during breeding season. Conflicts causing injury or death of Chinese giant salamanders are common if an individual enters the home range of a competitor. (Browne, et al., 2014)

  • Range territory size
    30 to 40 m^2

Home Range

Home ranges of Chinese giant salamanders average around 1,150 m^2. Females usually have a smaller home ranges than males. Though they are sedentary animals, they frequently move around their home range. The average daily distance a salamander moves is 300 m, but they can move up to 700 m in a single day. If displaced from their home range due to natural disasters like floods, Chinese giant salamanders will keep moving until they find another suitable habitat. Chinese giant salamanders maintain a territory within their home range. Male individuals hold a territory of about 40 m^2. Female individuals hold a territory of 30 m^2. (Browne, et al., 2014)

Communication and Perception

Chinese giant salamanders vocalize using barks, hisses, whistles, and cries. They have poor eyesight, so they rely on vibrations that they sense using nodes found on the sides of their bodies. These vibrations help them sense prey and other salamanders in their environment. During the breeding season, males secrete hormones during showering behaviors that attract females. (Browne, et al., 2014; Luo, et al., 2018)

Food Habits

Like other salamanders in the family Cryptobranchidae, Chinese giant salamanders are ambush predators. They are carnivorous generalists and eat crabs, frogs, water shrews, fish, other invertebrates, and other giant salamanders. Chinese giant salamanders are highly cannibalistic and have been found to supplement 27% of their diet by weight with other members of their species. Twigs, leaves, and gravel have also been found in their stomachs, though that is thought to be ingested while capturing prey. Chinese giant salamanders feed using buccal suction. The elastic cartilage in their jaws is shaped so that one side of their mandible becomes severely depressed, which causes asymmetrical suction. Prey is then sucked into their mouths. (Browne, et al., 2014; Nickerson, 2004)

  • Animal Foods
  • mammals
  • amphibians
  • fish
  • insects
  • terrestrial non-insect arthropods
  • other marine invertebrates

Predation

Chinese giant salamanders are apex predators of their ecosystem. Their only known natural predators are other members of their species. They are cryptids and use camouflage and skin secretion to fend off predators. These skin secretions are an acidic, sticky substance that repels predators. (Browne, et al., 2014)

Chinese giant salamanders are hunted extensively by humans (Homo sapiens). This practice, along with habitat loss and fragmentation, has caused a sharp population decline in the last 70 years. (Wang, et al., 2004)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • Chinese giant salamanders (Andrias davidianus)
    • Humans (Homo sapiens)

Ecosystem Roles

Chinese giant salamanders play an important role in Chinese freshwater river systems. They are top predators in these ecosystems and their extinction would harm the health of freshwater rivers and the overall biodiversity of their environment. Without Chinese giant salamanders, Chinese river systems would lose the top predator of freshwater crustaceans, insects, frogs, and fish. This could cause overpopulation in many of these species, resulting in a general decline in ecosystem health. A decline in ecosystem health, if this were to happen, would affect the millions of people in China that rely on these waters. (Browne, et al., 2014; Wang, et al., 2004)

Economic Importance for Humans: Positive

Chinese giant salamanders are a source of food and medicine in China. They are considered a delicacy and are both poached and farmed for food. The acidic skin secretion that Chinese giant salamanders make to repel predators is used for traditional medicinal purposes in China. (Browne, et al., 2014; Cunningham, et al., 2016)

Economic Importance for Humans: Negative

There are no known adverse of Chinese giant salamanders on humans.

Conservation Status

Chinese giant salamanders are listed as Critically Endangered on the IUCN Red List. They are also listed as a Class II Protected Species by the Wildlife Protection Law in China. This is due to overexploitation, habitat loss, habitat fragmentation, and loss of genetic diversity. Since 1980, Chinese giant salamander populations have declined rapidly and by 2000, 80% of their population had been eradicated.

Another factor going into the decline of wild populations is the wildlife trade. Chinese giant salamanders are easy targets for poachers and can be offered at restaurants for 200 to 450 USD per kg. Additionally, climate change and warming temperatures will affect their ability to find suitable home ranges. There are multiple facilities that farm and breed Chinese giant salamanders. This can be detrimental to populations of Chinese giant salamanders, as this depletes the genetic diversity of the species. Depleted genetic diversity can cause disease outbreaks like Ranavirus to be more common. (Browne, et al., 2014; Cunningham, et al., 2016; Liang, et al., 2004; Wang, et al., 2004; Zhang, et al., 2020)

There are many domestic and international efforts to conserve Chinese giant salamanders. Groups like EDGE, Shaanxi Normal University, the Zoological Society of London, and the Darwin Initiative are working on ways to spread public knowledge of Chinese giant salamander conservation. These institutes are looking for ways to conserve the habitats and populations of Chinese giant salamanders. (Cunningham, et al., 2016; Liang, et al., 2004)

Contributors

Lauren Hatch (author), Colorado State University, Brooke Berger (editor), Colorado State University, Galen Burrell (editor).

Glossary

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

keystone species

a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).

male parental care

parental care is carried out by males

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

piscivore

an animal that mainly eats fish

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

vibrations

movements of a hard surface that are produced by animals as signals to others

References

Browne, R., H. Li, Z. Wang, S. Okada, P. Hime, A. McMillan, M. Wu, R. Diaz, D. McGinnity, J. Briggler. 2014. The giant salamanders (Cryptobranchidae): Part B. Biogeography, ecology and reproduction. Amphibian and Reptile Conservation, 5/4: 30-50.

Chen, S., A. Cunningham, G. Wei, J. Yang, Z. Liang, J. Wang, M. Wu, F. Yan, H. Xiao, X. Harrison, N. Pettorelli, S. Turvey. 2018. Determining threatened species distributions in the face of limited data: Spatial conservation prioritization for the Chinese giant salamander (Andrias davidianus). Ecology and Evolution, 8/6: 3098-3108.

Cunningham, A., S. Turvey, F. Zhou, H. Meredith, W. Guan, X. Liu, C. Sun, Z. Wang, M. Wu. 2016. Development of the Chinese giant salamander Andrias davidianus farming industry in Shaanxi Province, China: conservation threats and opportunities. Oryx, 50/2: 265-273.

Jian, L., X. Yamei, L. Kaikun, H. Xiaoxi, P. Liangyue, L. Yun. 2007. Embryonic development and organogenesis of Chinese giant salamander, Andrias davidianus. Progress in Natural Science, 17/11: 1303-1311.

Liang, G., B. Geng, E. Zhao. 2004. "Andrias davidianus" (On-line). IUCN Red List. Accessed February 05, 2020 at https://www.iucnredlist.org/species/1272/3375181.

Liang, Z., W. Chen, D. Wang, S. Zhang, C. Wang, S. He, Y. Wu, P. He, J. Xie, C. Li, J. Merila, Q. Wei. 2019. Phylogeographic patterns and conservation implications of the endangered Chinese giant salamander. Ecology and Evolution, 9/7: 3879-3890.

Luo, Q., F. Tong, Y. Song, H. Wang, M. Du, H. Ji. 2018. Observation of the Breeding Behavior of the Chinese Giant Salamander (Andrias davidianus) Using a Digital Monitoring System. Animals, 8/10: 161. Accessed February 05, 2020 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211081/.

Nickerson, M. 2004. Asiatic Giant Salamanders and Hellbenders (Cryptobranchidae). Pp. 343-347 in M Hutkins, A Evans, J Jackson, D Kleiman, J Murphy, D Thoney, eds. Grzimek's Animal Life Encyclopedia, Vol. 6, 2nd Edition. Detriot: Thomson-Gale.

Sparreboom, M., A. Chang. 2019. "Andrias davidianus: Chinese Giant Salamander" (On-line). AmphibiaWeb. Accessed February 06, 2020 at https://amphibiaweb.org/species/3858.

Wang, X., K. Zhang, Z. Wang, Y. Ding, W. Wu, S. Huang. 2004. The decline of the Chinese giant salamander Andrias davidianus and implications for its conservation. Oryx, 38/2: 197-202. Accessed February 06, 2020 at https://www.cambridge.org/core/journals/oryx/article/decline-of-the-chinese-giant-salamander-andrias-davidianus-and-implications-for-its-conservation/98E36F71CD3FCC78C9E5499CEBBFF48F.

Zhang, Z., S. Mammola, Z. Liang, C. Capinha, Q. Wei, Y. Wu, J. Zhou, C. Wang. 2020. Future climate change will severely reduce habitat suitability of the Critically Endangered Chinese giant salamander. Freshwater Biology, 65/3: 1-10.