Mammals in Kikuchi Gorge
Kikuchi Gorge is a haven for animals that thrive in areas where forest and river ecosystems intersect. The gorge’s mammal residents represent some 20 species and include mice, moles, bats, martens (ten), giant flying squirrels (musasabi), and raccoon dogs (tanuki). As most of these animals are small and active mainly at night, they are seen only infrequently by visitors. Two of the most distinctive mammals in the gorge are dormice (yamane) and water shrews (kawanezumi).
The nocturnal yamane dormouse (Glirulus japonicus) grows to be 6.5 to 8 centimeters long and has a thick and fuzzy tail around 5 centimeters in length. Its fur is pale brown with a black stripe down its back, and it spends most of its time in trees, feeding on berries, nectar, and insects. Thanks to the small curved claws on its fingers and toes, it can run very fast upside down along the underside of tree branches. The dormouse hibernates for up to five months and lives between three and six years. While not a threatened species, it is scarce in Kyushu and has been designated a Natural Monument.
The kawanezumi water shrew (Chimarrogale platycephalus) is the only land mammal in Japan that gets its prey mainly from freshwater sources. Between 11 and 14 centimeters in length, it has dense and short grayish-black fur, and fringes of flattened, stiff hairs on both lateral edges of each finger and toe, which act as paddles. It swims in the river under the cover of darkness, hunting for aquatic insects, small crabs and shrimp, and fish. Rapidly flowing waters interspersed with calm pools, like the environment in Kikuchi Gorge, are its preferred habitat. The water shrew is common throughout Honshu but relatively rare in Kyushu and entirely absent from the island of Shikoku.
