Known as Lutra lutra whiteleyi (日本川獺 Nihon-kawauso), the Japanese River Otter had not been sighted since 1979.
A nocturnal mammal, the adult otter was 65 - 80 centimeters (25 - 31 inches) long, with a long tail measuring 45 - 50 centimeters (17 - 20 inches) and possessing a thick, dark brown fur that made it a target for hunters.
While the exact cause of the Japanese River Otter's demise is not known, it was quite plentiful throughout Japan until the 1930s when numbers rapidly declined. Industrial evolution for land development, pollutants, over-hunting are all being blamed with a big nod towards human industry being thought of as the chief culprit.
Foraging for food after dark, the otter eat lots of fish, shrimps, crabs, eels, beetles, sweet potatoes and watermelons.
It had multiple nests (homes) under rocks and bushes, and would visit a different one every few days. Territorial, it would mark its 16-kilometer (10-mile) diameter area with feces droppings every few miles. It would also apparently urinate in an area to show that it was courting a female.
It's the urine and feces, however which causes Machida Yoshiko (surname first), a professor emeritus at Kochi University, to believe that the otter may still be alive.
Although no one has seen a Japanese River Otter since 1979 in Niyodagawa (Niyodo River) near Susaki-shi (Susaki City), Kochi-ken (Kochi Prefecture)—see You Tube video below—he says there was a confirmed case of otter poop back in 1999.
"There was a case of otter droppings being confirmed in 1999. I think it is possible that they still exist, and I want to continue my investigations," he offers.
In fact, back in December of 1991, the prefectural government of Kochi-ken and Japan's environment agency searched Kochi-ken and not only found otter fur, but found three otter footprints and 10 poo samples. They did analyze the hair, and it did indeed come from a Japanese River Otter.
So visual proof of an otter or not, it appears as though the Japanese River Otter still existed at least into 1991. No sh!t. And that's the straight poop. So Professor Machida may have a point.
More poop was found in 1994 - along with the urine. Hoping to capture the otter on film, Kochi-ken's government set-up an infra-red camera (just a single one) in the area, but aside from some tanuki raccoon dogs - nothing. That was for a six month-period between October 1994 - April 1995.
But do you really need visual proof to know it is extinct? I've never been to Australia or seen Australia, but I'm pretty sure it exists because there is other physical proof. I once saw an Australian woman urinate after we performed some courting ritual.
Pee-pee jokes aside, and extinct or not, it's a crying shame this poor creature (and others on the Endangered list) even got to this point.