Skip to Main Contents

Japanese River Otter

Papercraft kit : The Japanese riverotter, urgent efforts are going on to verify the existence.

Rare Animals of Japan

Return to index

The Japanese River Otter, a member of the weasel family, reaches approximately 70 centimeters (28 inches) in length. The creature once widely inhabited midstream and downstream regions along rivers throughout Japan. However, its number has drastically diminished due to excessive pelt hunting.
The last official sighting of the Japanese River Otter was in the southern part of Kochi Prefecture in 1979, and since that time, no sighting of the otter has ever been confirmed. An official search to ensure its survival has recently gone under way.
The Japanese River Otter is currently classified as a ,Extinct [EX], species in the Red List.

The species was eventually considered to be the real source of the Japanese mythological figure, “Kappa”. Assembly instructions for paper sculptures of the Japanese River Otter as well as photo images of completed sculptures may be downloaded at this web site.

Sightings of Witness of Japanese River Otter have not been recorded since 1979.
However, research to verify of its existence is still being continued today.

Download - Parts sheet & InstructionsThis data was released in September, 1999.

Japanese River Otter - Animal Guide

  • Japanese River Otter - Mustelidae
  • Lutra nippon
  • 65 to 80 cm (26 to 32 in.) long
  • RED DATA BOOK (RDB) categories : Extinct [EX]

The Japanese River Otter (Lutra nippon), a member of the weasel family, is a nocturnal carnivore reaching 65 to 80 centimeters (26 to 30 inches) in length at maturity. The animal is characterized by its webbed-feet and streamlined body with dark brown back and light brown belly, as well as by its thick, long tail, which is very common to the weasel family. The species inhabits midstream and downstream regions along rivers and becomes active at night, searching for fish, shrimp, and crabs for prey. While the animal hunts for food mainly in the water, it spends the rest of its time on land sleeping and rearing its young.
Once abundantly dispersed throughout Japan, the Japanese River Otter was reduced to very small numbers during the Meiji and Taisho eras due to the hunting of its fur and liver, which was applied as a medicine for patients with Tuberculosis. Moreover, environmental changes, such as the decrease of habitats, breeding grounds, and prey due to large-scale river-related construction and industrial and agricultural water contamination, have accelerated the decrease of the animal. Many of the species were also killed by dogs, their natural enemies, as well as by cars.
Due to serious concerns about its possible extinction, the Japanese River Otter was designated as a special natural treasure of Japan in 1965. However, the last official sighting of the otter was in Kochi Prefecture in 1979, and the existence of the creature has not been corroborated since then. Non-governmental organizations as well as the Environment Agency and prefecture and city governments have commissioned searches by specialists in the field to ensure its survival. Recent sightings of the Japanese River Otter have been reported by various sources, but have not yet been officially confirmed.

The Back of Lutra nippon.
Lutra nippon catches its main meal, fish.

Habitat

The Japanese River Otter has widely inhabited river regions throughout Japan, encompassing the main islands, Hokkaido, Honshu, Shikoku, and Kyushu. It mainly inhabits midstream and downstream regions. In order to meet the needs of its active life and high energy consumption, which require a large amount of food, the otter travels over 10 kilometers (6.25 miles) along rivers and seashores where prey is plentiful. Although it is believed to live only in the southern region of Shikoku island, sightings of the animal have not been officially confirmed.

Main habitats of Japanese River Otter.

Photographed by Tetsushi Toyonaga

About RED DATA BOOK

The Red Data Book is a report compiled by the Environment Agency classifying various threatened animals in Japan and their present status. From a biological viewpoint, the Environment Agency has evaluated the extinction risk level of each individual taxon and compiled a list for the Red Data Book. However, the Book possesses no legal power to enforce regulations concerning threatened species.

The Red Data Book is broadly employed as fundamental information for advancing the preservation of threatened wild animals.

JAPANESE RED DATA BOOK CATEGORIES - based on IUCN Red List of Threatened Animals
EXTINCT EX A taxon considered to have become extinct in Japan.
EXTINCT IN THE WILD EW A taxon known to survive only under conservation or in captivity.
CRITICALLY ENDANGERED CR A taxon facing an extremely high risk of extinction in the wild in the immediate future.
ENDANGERED EN A taxon facing a very high risk of extinction in the wild in the near future though not critically endangered.
VULNERABLE VU A taxon facing a high risk of extinction in the wild in the medium-term future though not critically endangered or endangered.
NEAR THREATENED NT A taxon which can qualify for VULNERABLE in the future depending on its habitat conditions, although it is not facing a high risk of extinction at this present stage.
DATA DEFFICIENT DD A taxon about which there is not adequate information to make a direct, or indirect, assessment of its risk of extinction.
THREATENED LOCAL POPULATION LP A taxon facing a high risk of extinction in a certain locality among its limited specific habitats.

From Environment Agency press materials

Back to
Top