List of mammals of Japan

This is a list of mammal species recorded in Japan (excluding domesticated and captive populations). Of the 172 species of mammal found—112 native terrestrial mammals (those that are endemic are identified below; this number includes 37 species of bat), 19 introduced species, 40 species of Cetacea, and the dugong—161 are listed for the Japan region on the IUCN Red List of Threatened Species: of these, three taxa are critically endangered (Muennink's spiny rat, Yanbaru whiskered bat, and gloomy tube-nosed bat), twenty-two are endangered, eight are vulnerable, and eleven are near threatened; the Japanese sea lion and Bonin or Sturdee's pipistrelle are evaluated as extinct. Although on a global level the grey wolf is assessed as least concern, the two Japanese subspecies, Hokkaido wolf and Japanese wolf, are further recent extinctions; the 2020 Japanese Ministry of the Environment Red List also lists as extinct the Okinawa flying fox and Japanese river otter, as well as the subspecies Miyako little horseshoe bat [ja].
As of January 2023, for their protection, fifteen species and subspecies have been designated national endangered species by cabinet order in accordance with the 1992 Act on Conservation of Endangered Species of Wild Fauna and Flora.
The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature:
Sirenia is an order of fully aquatic, herbivorous mammals that inhabit rivers, estuaries, coastal marine waters, swamps, and marine wetlands. All four species are endangered.
The order Primates contains humans and their closest relatives: lemurs, lorisoids, monkeys, and apes.
Rodents make up the largest order of mammals, with over 40% of mammalian species. They have two incisors in the upper and lower jaw which grow continually and must be kept short by gnawing. Most rodents are small though the capybara can weigh up to 45 kg (99 lb).
The lagomorphs comprise two families, Leporidae (hares and rabbits), and Ochotonidae (pikas). Though they can resemble rodents, and were classified as a superfamily in that order until the early 20th century, they have since been considered a separate order. They differ from rodents in a number of physical characteristics, such as having four incisors in the upper jaw rather than two.
Eulipotyphlans are insectivorous mammals. Shrews and solenodons resemble mice, hedgehogs carry spines, gymnures look more like large rats, while moles are stout-bodied burrowers.
The bats' most distinguishing feature is that their forelimbs are developed as wings, making them the only mammals capable of flight. Bat species account for about 20% of all mammals.
There are over 260 species of carnivorans, the majority of which feed primarily on meat. They have a characteristic skull shape and dentition. Wolves and otters are now believed to be extinct in Japan.
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 terrestrial artiodactyl species, including many that are of great economic importance to humans. Artiodactyla also includes the infraorder Cetacea, which includes whales, dolphins and porpoises. Cetaceans are the mammals most fully adapted to aquatic life with a spindle-shaped nearly hairless body, protected by a thick layer of blubber, and forelimbs and tail modified to provide propulsion underwater.