The raccoon dog (Nyctereutes procyonoides), also known as the mangut (after its Evenk name) or tanuki (after its Japanese name), is a canid indigenous to East Asia. It is the only extant species in the genus Nyctereutes. It is considered a basal canid species, resembling ancestral forms of the family. The raccoon dog shares the habit of regularly climbing trees only with the North American gray fox, another basal species. Raccoon dogs are the only canids known to hibernate.
In reflection of their omnivorous diets, raccoon dogs have small and weak canines and carnassials, flat molars and relatively long intestines (1.5–2 times longer than other canids). They have long torsos and short legs. The winter fur is long and thick with dense underfur and coarse guard hairs measuring 120 mm in length. It is of a dirty, earth-brown or brownish-grey colour with black guard hairs. The abdomen is yellowish-brown, while the chest is dark brown or blackish. The summer fur is brighter and reddish-straw colored. A rare, white color phase occurs in this species in Japan and in China.
In early winter, they increase their subcutaneous fat by 18–23% and their internal fat by 3–5%. Animals failing to reach these fat levels usually do not survive the winter. During their hibernation, their metabolism decreases by 25%. In December, their physical activity decreases once snow depth reaches 15–20 cm, and will limit the range from their burrows to no more than 150–200 m. Their daily activities increase during February when the females become receptive and when food is more available.
Raccoon dogs are omnivores that feed on insects, rodents, amphibians, birds, fish, reptiles, molluscs, carrion and insectivores as well as fruits, nuts and berries. Raccoon dogs are able to eat toads which have toxic skin secretions by producing copious amounts of saliva to dilute the toxins. Raccoon dogs will modify their diets seasonally; in late autumn and winter, they feed mostly on rodents, carrion and feces, while fruit, insects and amphibians predominate in spring. In summer, they eat fewer rodents, and mainly target nesting birds and fruits, grains and vegetables.
