Aokigahara

The area around Mount Fuji is one of Japan's leading bird breeding grounds and a treasure trove of mammals.

An excerpt from the article 15 facts about Aokigahara

42 species of mammals have been confirmed to exist there. The Aokigahara area is characterized by a particularly high population density of the Asian black bear. Other mammals living there include Japanese macaques, deer, wild boars, Japanese weasels, Japanese squirrels, and others.