Japanese giant salamander

Japanese giant salamander
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Caudata
Family: Cryptobranchidae
Genus: Andrias
Species: A. japonicus
Binomial name
Andrias japonicus
(Temminck, 1837)
Synonyms

Megalobatrachus japonicus (Reviewed by Sato 1943)[1]

The Japanese giant salamander (Andrias japonicus) is endemic to Japan, where it is known as Ōsanshōuo (オオサンショウウオ/大山椒魚), literally meaning "giant pepper fish". With a length of up to almost 1.5 m (5 ft),[2] it is the second-largest salamander in the world, only being surpassed by the very similar and closely related Chinese giant salamander (A. davidianus).

Behavior

A pair of captive Japanese giant salamanders
Andrias japonicus Skull

The Japanese giant salamander, being restricted to streams with clear, cool water, is entirely aquatic and nocturnal. Unlike other salamanders, which lose their gills early in their lifecycles, they only breach their heads above the surface to obtain air without venturing out of the water and onto land. Also due to their large size and lack of gills, they are confined to flowing water where oxygen is abundant.[3] When threatened, these salamanders can excrete a strong-smelling, milky substance with an odor resembling Japanese pepper (hence its common Japanese name, giant pepper fish). It has very poor eyesight, and possesses special sensory cells covering its skin, running from head to toe, the lateral line system. These sensory cells' hair-like shapes detect minute vibrations in the environment, and are quite similar to the hair cells of the human inner ear. This feature is essential for its hunting because of its poor eyesight. It feeds mainly on insects, frogs and fish. It has a very slow metabolism and lacks natural competitors. It is a long-lived species, with the captive record being an individual that lived in the Natura Artis Magistra, the Netherlands, for 52 years.[2] In the wild, they may live for nearly 80 years.

History

The Japanese giant salamander was first catalogued by Europeans when the resident physician of Dejima Island in Nagasaki, Philipp Franz von Siebold, captured an individual and shipped it back to Leiden in the Netherlands, in the 1820s. The species was designated as a special natural monument in 1951, and has been protected.[4]

Status

The Japanese giant salamander is threatened by pollution, habitat loss (among other changes, by the silting up of the rivers where it lives), and overcollection. It is considered near threatened by IUCN, and is included on CITES Appendix I.[5] It can be found on the islands of Kyushu, Honshu, and Shikoku in Japan. In the past, they were fished out of rivers and streams as a source of food, but hunting has ceased because of protection acts.

Lifecycle

Japanese giant salamanders remain in bodies of water their entire lives. During mating season, sexually mature adults go up stream into the mountains to spawn and lay eggs. Large males guard a den and are known as denmasters. They mate with several females throughout the season. Smaller males who do not have a den may attempt to enter the den and fertilize some of the eggs. The male releases milt over the eggs laid by the female. The denmaster displays parental care and guards the eggs and fans water over them to increase oxygen flow.[6] Larvae emerge from the fertilized eggs, and lose their gills once they metamorphose into adults.

Cultural references

Ukiyo-e print by Utagawa Kuniyoshi depicting a giant salamander being stabbed by the samurai Hanagami Danjō no jō Arakage

The Japanese giant salamander has been the subject of legend and artwork in Japan, for example, in the ukiyo-e work by Utagawa Kuniyoshi. The well-known Japanese mythological creature known as the kappa may be inspired by the Japanese giant salamander.[7]

See also

References

  1. ↑ "Amphibian Species of the World - Andrias japonicus (Temminck, 1836)". Research.amnh.org. Retrieved 2010-02-04.
  2. 1 2 Andrias japonicus - Amphibiaweb
  3. ↑ The Encyclopedia of Reptiles and Amphibians. Facts on File Inc. 1986. ISBN 0-8160-1359-4.
  4. ↑ オオサンショウウオ (in Japanese). The Agency for Cultural Affairs. Retrieved 2011-09-24.
  5. ↑ Japanese giant salamander. ARKive. Retrieved 2008-09-19.
  6. ↑ Okada, Fukuda, Takahashi, Sumio, Yukihiro, Mizuki (12 November 2014). "Paternal care behaviors of Japanese giant salamander Andrias japonicus in natural populations". Journal of Ethology.
  7. ↑ "River Monsters" programme 6 Series 3 directed by Duncan Chard, screened in UK on ITV1 14.02.2012 at 19.30

External links

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