Japanese Giant Salamander: Size, Range and Status
The Japanese giant salamander (Andrias japonicus) is a huge, fully aquatic salamander from the rivers of western Japan. The Detroit Zoo reports lengths of more than 4 feet and weights up to 88 pounds, with a median life expectancy of over 50 years. It is listed as Vulnerable by the IUCN and is a Special Natural Monument in Japan. It is not the world’s largest amphibian. That title belongs to the Chinese giant salamander.
The Japanese giant salamander is one of only three living giant salamander species. It spends its whole life in cold, clean rivers, and it takes about 15 years to reach sexual maturity.
Many pages call it the largest amphibian in the world. That is not correct. This guide covers its real size, where it lives, what it eats and why it is declining. For its larger cousin, see our Chinese giant salamander guide.
How this was made: prepared with AI assistance and checked against the sources listed at the end. Images are AI-generated illustrations, not photographs of real animals or products.
Key Takeaways
- It is more than 4 feet long and can weigh up to 88 pounds, per the Detroit Zoo.
- The Chinese giant salamander is the largest living amphibian, not the Japanese one.
- It lives in rivers of southwest Honshu, Kyushu and Shikoku.
- It is Vulnerable on the IUCN Red List and a Special Natural Monument in Japan.
- Weirs, dams, pollution and hybridization with introduced Chinese giant salamanders are major threats.
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How big is the Japanese giant salamander?
The Detroit Zoo reports a length of more than 4 feet (about 1.2 m) and a weight of up to 88 pounds (about 40 kg). Some pages online give other figures, such as 5 feet and 55 pounds, but we could not trace those to a primary source, so we do not use them.
The animal has a wide, flat head, small eyes and a wrinkled body built for life on a river bottom. It is fully aquatic and never leaves the water.
Is it the largest amphibian?
No. Smithsonian Magazine reports that the largest Chinese giant salamander on record, a London Zoo animal now in the Natural History Museum, measures 5 feet 9 inches. The Zoological Society of London calls it the largest of the roughly 8,000 amphibian species alive today.
Edge of Existence gives up to 1.8 m for the Chinese species. The Japanese species is very large, but the Chinese species is larger.
| Species | Reported size | IUCN status |
|---|---|---|
| Japanese giant salamander | More than 4 ft, up to 88 lb (Detroit Zoo) | Vulnerable |
| Chinese giant salamander | Up to 1.8 m; London specimen 5 ft 9 in | Critically Endangered |
Where it lives
The species lives in southwest Honshu, Kyushu and Shikoku. It needs rivers with clean water and nest banks where adults can shelter and breed.
In good habitat with little pollution, few barriers and suitable nest banks, a Frontiers paper estimates 40 to 69 animals per kilometer of river. That figure shows how thinly spread even healthy populations are.
What it eats and how long it lives
The Detroit Zoo lists fish, small mammals and small invertebrates as its diet.
The same zoo reports a median life expectancy of more than 50 years. Animals reach sexual maturity at about 15 years, according to the Frontiers paper, so a lost adult takes a very long time to replace.
Protection and status
The IUCN lists the species as Vulnerable (2022). In Japan it is designated a Special Natural Monument. Killing or collecting one can bring a fine of up to 300,000 yen and up to five years in prison.
It is also listed in CITES Appendix I, and collection is prohibited throughout its range. It is not an animal for private keeping.
Why it is declining
The Frontiers paper says populations have declined for close to a century, with the steepest fall between the 1950s and 1970s. Dams, weirs and concrete embankments split rivers into pieces. Some stretches of the Nawa River have up to 15 weirs within one kilometer.
Pollution matters too. Downstream of a pig farm, the paper recorded ammonium of 6.83 mg/L, compared with 3.57 mg/L upstream, and dissolved oxygen of 2.6 to 2.7 mg/L, compared with 4.6 to 5.5 mg/L upstream.
- Dams, weirs and concrete banks block movement and remove nest sites.
- Runoff from animal farms lowers oxygen and adds ammonium.
- Habitat loss remains a threat for some local populations.
- Hybridization with introduced Chinese giant salamanders is increasingly common.
Frequently Asked Questions
How big is a Japanese giant salamander?
The Detroit Zoo reports more than 4 feet (about 1.2 m) and up to 88 pounds. Other sites give different figures, which we could not verify.
Is the Japanese giant salamander the biggest amphibian?
No. The Chinese giant salamander is larger. The largest on record measured 5 feet 9 inches.
Where does it live?
In rivers of southwest Honshu, Kyushu and Shikoku in Japan.
How long does it live?
The Detroit Zoo reports a median life expectancy of more than 50 years.
Is it endangered?
The IUCN lists it as Vulnerable. In Japan it is a Special Natural Monument, and CITES Appendix I covers it.
Can you keep one?
No. Collection is prohibited throughout its range, and Japanese law punishes killing or collecting one with fines and prison.
Bottom Line
The Japanese giant salamander survives in the same rivers it has used for millions of years, but dams and pollution now cut those rivers into pieces. Because the animals mature slowly, recovery is also slow.
To compare it with other giants, read our guides to the Asian giant salamander and the giant salamander group.
Sources
- Detroit Zoo: Japanese Giant Salamander, accessed 31 October 2026
- Frontiers in Amphibian and Reptile Science (2024): Japanese giant salamander conservation perspective, accessed 31 October 2026
- Smithsonian Magazine: New giant salamander species, accessed 31 October 2026
- Edge of Existence: Chinese giant salamander, accessed 31 October 2026
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