Fauna
Amphibian

Japanese Giant Salamander

Andrias japonicus

Also known as Osancho, Hanzaki

Japanese giant salamanders navigate cold mountain riverbeds using chemical sensors and lateral line systems to pinpoint prey in dark waters. Adult males aggressively defend underwater burrows, known as den sites, where females lay long strings of eggs that the male fertilizes and guards for months. With skin so wrinkled it maximizes surface area for underwater cutaneous respiration, these ancient amphibians can remain submerged indefinitely without surfacing for air.

AquaticNocturnalAmphibian
Japanese Giant Salamander reference1 / 7
Salamandra2021 / CC BY-SA 4.0 · cc-by-sa
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VulnerableConservation statusIUCN Red List categoriesLCNTVUENCREWEXVulnerableRed List categories, explained →
Key facts
Diet & preyFreshwater Crabs, Stream Fish, Frogs
Predators
  • Herons (juveniles)
  • Larger Conspecifics
ThreatsDam construction, concrete riverbanks, pollution, and hybridization
HabitatsCold, fast-flowing mountain streams and clear rivers
Life span50–80 years
Classification
  1. OrderCaudata
  2. FamilyCryptobranchidae
  3. GenusAndrias
  4. SpeciesAndrias japonicus
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Delivers a painful bite with powerful jaws if handled or cornered; observe safely from riverbanks.
Why it is dangerous
Possesses exceptionally strong muscular jaws and small sharp teeth that can inflict deep lacerations if grabbed.
How to recognize a risky encounter
Identified by a broad flattened head, wrinkled mottled grey skin, tiny lidless eyes, and a thick paddle-like tail.
What to do
Never reach under submerged rocks or touch salamanders in the wild; observe quietly from dry bank edges.
What to notice
Look for a massive dark brown amphibian resting motionlessly along clean pebble-bottom river stretches.
Support conservation
Avoid revealing precise location coordinates for nesting burrows and stay out of protected spawning waters.
Responsible observation
  • Night Spotting: Look into clear, fast-flowing streams after dusk using a red flashlight to spot active adults.
  • Stream Etiquette: Refrain from disturbing riverbed stones or wading near undercut banks where nesting burrows lie.
  • Keep Distance: Maintain a respectful distance on the shoreline and never attempt to handle wild individuals.
Related species
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