Nyctereutes procyonoides

Geographic Range

Nyctereutes procyonoides is native to eastern Siberia, northern China, North Vietnam, Korea, and Japan. Between 1927 and 1957, the fur-farming industry introduced from 4,000 to 9,000 raccoon dogs to the European and Asian U.S.S.R. Today, N. procyonoides is widespread throughout northern and western Europe in countries including Finland, Sweden, Norway, Poland, Romania, Czech Republic, Slovakia, Germany, France, Austria, and Hungary.

• Biogeographic Regions
• palearctic palearctic
  • introduced introduced
  • native native

Habitat

Nyctereutes procyonoides is found in subarctic and subtropical climates. It prefers forest, forest borders, or dense vegetation— areas of thick underbrush, marshes, and reedbeds— for dense cover. Regions bordering water are also favored. Raccoon dogs are found from near sea level to greater than 3,000 m. Nyctereutes procyonoides also has been known to encroach upon human habitats while scavenging for food.

• Habitat Regions
• temperate temperate
• polar polar
• terrestrial terrestrial

• Terrestrial Biomes
• taiga taiga
• forest forest
• mountains mountains

• Other Habitat Features
• suburban suburban
• riparian riparian

Physical Description

Nyctereutes procyonoides has the appearance of a small fox-like canid with the fur markings similar to those of raccoons ( Procyon lotor ). They have small heads (greatest length 133 mm) with pointed, low-profile rostra. The dental formula is i 3/3, c 1/1, p 4/4, m 2 or 3/3, total 42 or 44. Raccoon dogs have reduced carnassials and relatively large molars. Height ranges from 38.1 to 50.8 cm. Length from head to rump is 50 to 68 cm with a tail length of 13 to 25 cm. Legs are short, and overall the body is stocky. Body weight ranges from 4 to 6 kg in the summer to 6 to 10 kg in the winter before hibernation. On average, individuals in Europe tend to be larger than those in China and Japan. The existence of several subspecies of N. procyonoides may account for this discrepancy. Mass of adult females in China and Japan is 0.5kg greater than males.

The fur of N. procyonoides is dense and soft. Markings on the head include a white muzzle, white face, and black fur surrounding the eyes. A black marking runs across both shoulders and down the back, forming the shape of a cross. Ears are rounded and short; black hair one the ears trims the white hair inside. Body color is dusky brown to yellow-brown dorsally but varies greatly. Long guard hairs, found throughout the dorsal side, are tipped black. On the belly, the fur is lighter brown or tan. Limbs and chest are blackish-brown. Raccoon dogs have thick, bushy tails that are black dorsally and light-yellow ventrally with a black tip. Winter pelage is thicker and darker than summer pelage.

Nyctereutes procyonoides goes through a molt in the summer between July and October. The winter pelage grows in during September, October, and November. Raccoon dogs also have a spring molt that begins in April when the underfur is shed. The summer coat is in by mid-June.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Not much is known about the mating behavior of N. procyonoides . Studies have shown that raccoon dogs form mating pairs from year to year, and monogamy among pairs has been reported in raccoon dogs found in Finland. In regions of home-range overlap, pairs do not interact. Polygamy has been reported in captive individuals.

During mating, females are courted by 3 to 4 males. There is little fighting among males for mates. In captivity, both scent marking and male-female interaction increased during proestrus. Pair bonds form before copulation and remain until after offspring have become independent. An inverted U-shaped tail posture in males is associated sexual arousal and expresses dominance. After pairs mate and the female gives birth, males and females spend a significant amount of time together raising the pups.

• Mating System
• monogamous monogamous
• polygynous polygynous

Females come into heat once a year, after hibernation. Data from raccoon dogs in captivity show that estrus lasts from 3 to 5 days. Copulation occurs at the end of the cold part of winter in January, February, or March, depending on geographic location. Copulation ties are an average of 6 minutes. Gestation period ranges from 59 to 64 days. Nyctereutes procyonoides usually gives birth in dense vegetation or in burrows that have been abandoned by foxes or badgers. Average litter size is 5 to 7, with the highest of 19 pups reported. Pups are born blind and have soft, black fur. Weight ranges from 60 to 115 g at birth depending on subspecies. Between the 9th and 10th day, pups' eyes open and teeth are visible by 14 to 16 days. Mothers wean their pups between 30 to 40 days of age. At this time, the typical face mask and the guard hairs are fully developed. Mass and size increase in a linear fashion until 50 to 60 days. Offspring are the size of small adults at 80 to 85 days of age. The offspring will reach sexual maturity at 9 to 11 months.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

During late pregnancy, a female’s mate brings her food. After she gives birth, the male also has a role in postnatal care. The young are weaned at 30 to 40 days; the male typically watches over them while the female hunts for food. The male may also hunt while the female watches the young. At 4 months, the pups begin learning how to hunt by watching their parents. In a short time, they are self-supporting although they may remain with their parents, and hunt as a family, until the fall. At that point, they are independent. Between 9 to 11 months the offspring will have reached sexual maturity.

• Parental Investment
• altricial altricial
• pre-hatching/birth
  • provisioning
    • male
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

The lifespan of N. procyonoides in the wild is not known. In a study of trapped animals, the oldest males were in an age class of 5.5 years, and the oldest females were in an age clasee of 7.5 years. Of 320 raccoon dogs captured, 68.4% of the population was younger adults. In captivity, longevity can be greater than 14 years.

Behavior

Radiotelemetry studies show that raccoon dogs live and hunt in pairs or small family groups. In most sightings by humans, however, they are solitary. It is unknown whether the duration of the pair bond formed during reproduction lasts the entire year. When sleeping or resting, pairs usually remain in contact with one another. Social grooming is also important in raccoon dogs. This behavior is linked to the dark facial mask in both this species and bat-eared foxes ( Otocyon ).

Although some studies have shown the species to be primarily nocturnal, recent studies show regular diurnal, crepuscular, and nocturnal activity. Increased duration of activity is probably due to the need to find enough small food items to eat. Raccoon dogs are not cursorial. These animals forage on the ground or on low vegetation. They also are able to swim or dive for food. Nyctereutes procyonoides relies on its sense of smell while hunting and foraging because it has relatively poor vision for a member of the family Canidae . With its nose at the ground level, it wanders in search for food. Raccoon dogs are not fast animals, but they are relentless in their search for food. They are typified as collectors or gatherers.

Raccoon dogs hibernate in pairs. Hibernation begins in November and may extend through early April, depending on the local climate. An individual may gain as much as 50% of its body weight before hibernation. Hibernation is not absolutely necessary for this species. If an individual is unable to store enough fat beforehand, it will have to emerge from the den on warm winter days to forage. For this reason, some individuals may not hibernate at all. In the southernmost part of the range, raccoon dogs do not hibernate.

• Key Behaviors
• terricolous
• natatorial natatorial
• diurnal diurnal
• nocturnal nocturnal
• crepuscular crepuscular
• motile motile
• hibernation hibernation
• social social

Home Range

A male-female pair will share the same home range and may remain close together when active. In areas of home-range overlap, neighbors do not interact. This confirms that N. procyonoides is not territorial. Overall home range of this species varies from 2.8 to 200 ha. Population density of Japanese raccoon dogs (ranging from 0.46 to 0.86/ha) is greater than in Europe (ranging from 0.0014 to 0.048/ha). This disparity is due to environmental differences and the existence of a different subspecies in each area.

Communication and Perception

Nyctereutes procyonoides uses latrines to communicate with other members of the species. A latrine is a definite site where an entire group of raccoon dogs will both urinate and defecate. Research has suggested that raccoon dogs use the latrine for information exchange among family members as well strangers. The animals modify their behavior based on olfactory recognition of conspecific individuals when they encounter one another.

Raccoon dogs are vocal canids. However, they do not, like all other representatives of the order, bark. They may whine, whimper, or mew; these are all responses coupled with friendly or submissive behavior. They may growl when frightened or when being aggressive.

In addition to scent cues and vocal communication, these animals use some body postures--such as tail position--to indicate dominance and readiness to mate. Tactile communication if probably important between parents and offspring, as well as between mates.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Nyctereutes procyonoides is an opportunistic omnivore. On land, it hunts insects, small rodents, amphibians, birds, and eggs. It also fishes in lakes, rivers, and streams using its paws to scoop prey out of the water. It also dives underwater in search for its meal. In addition, raccoon dogs eat mollusks, snakes, and lizards; on the seashore, crabs, sea urchins, and sea carrion are also consumed.

Raccoon dogs also eat plant material— including stems, roots, leaves, bulbs, fruits, nuts berries, and seeds— according to the season and location. During the fall, they eat mainly vegetables, including a variety of fruits, wild berries, and seeds such as oats. In the winter, when food sources are limited, they may survive on human garbage and carrion. In Japan, raccoon dogs rely heavily on garbage, insects, fish, crabs, and plants such as buckthorn ( Rhamnus ), hornbeam ( Carpinus ), and a shrub ( Aucuba japonica ). In Finland, during the summers, they rely on small mammals ( Mus musculus ), plants, and amphibians; during the winter, they rely on carrion, small mammals, and plants.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• fish
• eggs
• carrion carrion
• insects
• mollusks
• aquatic crustaceans
• echinoderms

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts
• fruit

Predation

Not much is known about the antipredator adaptations of N. procyonoides . Wolves, lynx, wolverines, martens, golden eagles, sea eagles, eagle owls, and domestic dogs are all predators of this species. In the former U.S.S.R. and Finland, humans are also major predators of raccoon dogs. Raccoon dogs are used for commercial trapping and fur farming by humans. In Japan, raccoon dogs are also eaten by humans.

Ecosystem Roles

Raccoon dogs are an important food source for various larger canids as well as humans. They are also responsible for controlling insect and rodent populations, but, because they are generalists, they do not affect any one species on a large scale. Nyctereutes procyonoides is prone to infections including mange, rabies, piroplasmosis, and helminths.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Japan, Finland, and the former U.S.S.R. benefit from the trading of the fur of N. procyonoides . Pelts are used for necklets, collars, and fur coats. In Japan, people eat raccoon dogs as well as use their fur for bristles for calligraphy brushes. The bones have also been used medicinally and as an aphrodisiac.

• Positive Impacts
• body parts are source of valuable material
• source of medicine or drug source of medicine or drug

Economic Importance for Humans: Negative

Raccoon dogs are capable of living in areas close to humans. They are often exterminated because they are carriers of diseases that can be trasmitted to humans and other animals. They are also killed for preying on small-game animals and other wildlife.

• Negative Impacts
• injures humans
  • carries human disease
• causes or carries domestic animal disease causes or carries domestic animal disease

Conservation Status

Nyctereutes procyonoides is not an endangered species.

Other Comments

The success of N. procyonoides is in part due to its great adaptability, high reproductive rate, tolerance of human presence, and opportunistic foraging behavior. Nyctos means "night" and ereuna means "seeking." Prokyon means "before dog" and eidos means "form." The species is not closely related to any other member of Canidae. It has the unusual characteristic of supernumerary chromosomes and shares homologous chromosomes with members of Felidae. For these reasons, the taxonomic position of N. procyonoides is not clear. Taxonomists recognize five to six subspecies of N. procyonoides .

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Kelly Carr (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Colby, C. 1965. Wild Dogs . New York: Duell, Sloan, Pearce.

Kauhala, K., E. Helle, K. Taskinen. 1993. Home range of the raccoon dog ( Nyctereutes procyonoides ) in southern Finland. Journal of Zoology , 231: 95-106.

Sheldon, J. 1992. Wild Dogs : The Natural History of the Nondomestic Canidae . San Diego: Academic Press.

Ward, O., D. Wurster-Hill. 1990. Mammalian Species: Nyctereutes procyonoides . The American Society of Mammalogists , No. 358: 1-5. Accessed February 02, 2004 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/ .

Ward, O., D. Wurster-Hill. 1989. Ecological studies of Japanese raccoon dogs, Nyctereutes procyonoides. Journal of Mammalogy , 70: 330-334.

Yamamoto, I. 1984. Latrine Utilization and Feces Recognition in the Raccoon Dog. Journal of Ethology , 2: 47-54.