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Monday, September 2, 2013

Species Fact Profile: Japanese Giant Salamander (Andrias japonicus)

Japanese Giant Salamander

Andrias japonicus (Temminck, 1837)

Range:  Japan (N. Kyushu Island, W. Honshu Island)
Habitat:  Mountain Streams
Diet:  Fish, Salamanders, Aquatic Invertebrates
Social Grouping: Solitary
Reproduction: Congregate at nest sites in August, where the females lay 400-500 eggs in strings; these strings are fertilized by multiple males, who protect the eggs until they hatch 12-15 weeks later
Lifespan:  55 Years (Captivity)
Conservation Status: IUCN Near Threatened, CITES Appendix I

  • The second largest salamander in world (after closely related Chinese giant), they can measure up to 1.5 meters long and weigh 25 kilograms.  The large boy size (and lack of gills) are thought to limit the salamander to the coldest, most oxygen-rich streams
  •  Skin - mottled gray, black, and cream - is heavily wrinkled; the tiny eyes are barely visible on top of the broad head
  •  Primarily nocturnal, it has poor vision and finds prey based on smell and touch; days are spent hidden under rocks or in underwater caves
  •  Metabolic rate is extremely slow, allowing the salamander to go for weeks at a time without eating
  • Metamorphosis is incomplete – the species does not develop eyelids, retains a single pair of closed gill slits on the neck, and has vestigial lungs
  • Males are very aggressive towards one another during breeding and nesting; sometimes killing (and subsequently eating) one another during disputes
  •  When threatened, the salamander excretes a quick-hardening gelatinous substance as defense mechanism; this secretion, which is said to smell like pepper, is responsible for the Japanese name of “giant pepper fish”
  •   The meat of this species is considered a delicacy and it is hunted for its flesh; they are also threatened by the pollution of their waterways due to soil erosion and siltation
  • Conservation efforts to save the Japanese giant salamander include the construction of artificial breeding holes incorporated into new waterways

Zookeeper's Journal: I will never forget my first encounter with a Japanese giant salamander... mostly because it is the only time in my life I was ever physically intimidated by an amphibian.  On a college field trip to the Reptile House of the Buffalo Zoo, we were shown around the various exhibit galleries (the building was, at the time, closed to the public for renovation).  At the end of the tour, we were taken into a back area to meet the crown jewels of the collection - the Japanese giant salamanders.  The behemoths were lying in bath tubs beneath screen lids.  The keeper who was guiding us lifted the lid to offer us a better look, and the salamander looked up at us with beady little eyes, barely visible... and began to crawl out of the tub.  For reasons I can't describe, that salamander unnerved me more than most large carnivores ever have.  They can be pretty vicious towards one another, sometimes ripping off limbs during combat or their aggressive mating rituals.  This has partially explained why the species has not bred successful in western zoo collections - zoo curators are unwilling to risk damage to their precious rarities.  Japanese zoos, I am told, let the salamanders rip each other up and breed.

On a completely unrelated side note, this species (and its extinct fossil relatives), served as the inspiration behind one of the greatest, most brilliant pieces of political/social satire ever written, Karel Capek's War with the Newts.

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