A photo of the "last" Japanese river otter
The 2009 sketch
The 2020 infrared trail camera possibly showing an otter
Japanese river otter
Lutra lutra whiteleyi
The Japanese River Otter (Lutra lutra whiteleyi) is a supposedly extinct subspecies (or arguably its own species) of otter that lived throughout Japan. The Japanese river otter had round eyes, webbed paws, brownish tea-coloured fur, a body length of about 70 centimetres and a thick tail about 45 centimetres long. It inhabited the ocean as well as rivers and marshes, where it fed on fish, crayfish, and crabs. They were nocturnal, only leaving the den after dark for food.
Due to overhunting and habitat destruction, Japanese river otters were declared extinct in 2012. The last "official" sighting was in 1979, when a Japanese river otter was photographed at the mouth of the Shinjo River in the sparsely populated Kōchi Prefecture.
In December of 1991, the Japanese ministry of environment and the Kōchi Prefectural government started a search for Japanese river otters. Although they were unsuccessful in photographing or capturing a specimen, they found three different trackways and 10 excrement samples. DNA testing on the hair showed it did come from an otter.
Two years after the hair and excrement samples were found, a group of zoologists found a sample of otter urine. This is important since otters tend to urinate during mating, implying there is more than one remaining otter.
In 2009, an artist from Shikoku claimed to have witnessed a Japanese river otter and drew it in detail. Yoshihiko Machida, a professor from the University of Kōchi believed him to be "highly trustable." His drawing also included very obscure details about the Japanese river otter's appearance, like its wide, conical tail.
In the 2010s, sightings increased across southern Japan, particularly around the Ehime and Nagasaki Prefectures, with more than 15 sightings in 2012 alone. In 2017, an otter was filmed on a trail camera on Tsushima Island, in the Nagasaki Prefecture. Some dismissed the video as showing a sea otter, but this is unlikely, as they don't live in the area. A more likely explanation is a vagrant Eurasian otter, which could have been blown off course from South Korea.
In October of 2020, the Japanese Otter Club, a group of amateur naturalists and researchers set up a series of infrared trail cameras near a group of claw marks and burrows on a bank off the Niyudo River. Burrowing is a known behaviour in otters, though no other animals in the area build burrows. Surprisingly, they managed to photograph what appears to be an otter (above).