Raccoon dog

Appearance

Raccoon dog skulls greatly resemble those of South American foxes, particularly crab-eating foxes, though genetic studies reveal they are not closely related. Their skulls are small, but sturdily built and moderately elongated, with narrow zygomatic arches. The projections of the skull are well developed, the sagittal crest being particularly prominent in old animals.

In reflection of their omnivorous diets, raccoon dogs have small and weak canines and carnassials, flat molars and relatively long intestines . They have long torsos and short legs. Total lengths can range from 45 to 71 cm . The tail, at 12 to 18 cm long, is short, amounting to less than 1/3 of the animal's total length and hangs below the tarsal joints without touching the ground. The ears are short and protrude only slightly from the fur.

Weights fluctuate according to season: in March they weigh 3 kg , while in August to early September males average 6.5–7 kg , with some individuals attaining a maximal weight of 9–10 kg . Specimens from Japanese and Russian studies have been shown to be on average larger than those from Chinese studies.

The winter fur is long and thick with dense underfur and coarse guard hairs measuring 120 mm in length. The winter fur protects raccoon dogs from low temperatures ranging down to −20° to −25 °C. It is of a dirty, earth-brown or brownish-grey colour with black guard hairs. The tail is darker than the torso. A dark stripe is present on the back which broadens on the shoulders, forming a cross shape. The abdomen is yellowish-brown, while the chest is dark brown or blackish. The muzzle is covered in short hair, which increases in length and quantity behind the eyes. The cheeks are coated with long, whisker-like hairs. The summer fur is brighter and reddish-straw coloured.

A rare, white color phase occurs in this species in Japan and in China.

Naming

The three recognized subspecies of raccoon dog are:
- N. p. orestes Thomas, 1923 - Yunnan (China)

- N. p. ussuriensis Matschie, 1907- Russia (Ussuri and Amur territories), northeastern China and Korea, Europe
Distinguished from N. p. procyonides by its larger size and denser, longer hair.[2] After being introduced to western USSR, it now occurs throughout Northern, Central and Eastern Europe.

- N. p. viverrinus Beard, 1904 - Japan
A small subspecies with smaller teeth and skull compared to those of N. p. ussuriensis, it has the silkiest pelt among raccoon dogs.
There is some debate in the scientific community regarding speciation between the other subspecies of raccoon dog and the Japanese subspecies in that due to chromosome, behavioral and weight differences, the Japanese raccoon dog could be considered a separate species from the other subspecies. Genetic analysis confirmed unique sequences of mtDNA, classifying the Japanese raccoon dog as a distinct isolation species, based on evidence of eight Robertsonian translocations. The International Union for Conservation of Nature Canid Group's Canid Biology and Conservation Conference in September 2001 rejected the classification of the Japanese raccoon dog as a separate species, but its status is still disputed, based on its elastic genome.

Behavior

Raccoon dogs are the only canids known to hibernate. 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 areas such as Primorsky Krai and their introduced range, raccoon dogs only hibernate during severe snowstorms. 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.

Reproduction

The mating season begins from early February to late April, depending on location. Raccoon dogs are monogamous animals, with pair formations usually occurring in autumn. Captive males, however, have been known to mate with four or five females. Males will fight briefly, but not fatally, for mates. Copulation occurs during the night or dawn and will last 6–9 minutes on average. Estrus lasts from a few hours to six days, during which females will mate up to five times. Females will enter estrus again after 20–24 days, even when pregnant.

The gestation period lasts 61–70 days, with pups being born in April–May. Litter sizes on average consist of 6–7 pups, though 15–16 pups can be born in exceptional cases. First-time mothers typically give birth to fewer pups than older ones. Males take an active role in raising the pups. This male role is very significant, as demonstrated by early releases in 1928 of pregnant females without males resulting in very limited success at introduction, while later releases of pairs from 1929 until the 1960s resulted in the raccoon dog's now extensive introduced European range.


At birth, pups weigh 60–110 grams, and are blind and covered in short, dense, soft wool lacking guard hairs. Their eyes open after 9–10 days, with the teeth erupting after 14–16 days. Guard hairs begin to grow after 10 days, and first appear on the hips and shoulders. After two weeks, they lighten in colour, with black tones remaining only around the eyes. Lactation lasts for 45–60 days, though pups will begin eating food brought to them as early as the age of three weeks or one month. They reach their full growth at the age of 4.5 months. Pups will leave their parents in late August–September. By October, the pups, which by then resemble adults, will unite in pairs. Sexual maturity is reached at 8–10 months. Their longevity is largely unknown; animals 6–7 years of age have been encountered in the wild, while captive specimens have been known to live for 11 years.

Food

Raccoon dogs are omnivores that feed on insects, rodents, amphibians, birds, fish, reptiles, molluscs, carrion and insectivores as well as fruits, nuts and berries. Among the rodents targeted by raccoon dogs, voles seem to predominate in swampy areas, but are replaced with gerbils in flatland areas such as Astrakhan. Frogs are the most commonly taken amphibians; in the Voronezh region, they frequently eat fire-bellied toads, while European spadefoot toads are usually taken in Ukraine. Raccoon dogs are able to eat toads which have toxic skin secretions by producing copious amounts of saliva to dilute the toxins. They will prey on waterfowl, passerines and migrating birds. Grouse are commonly hunted in their introduced range, and many instances of pheasant predation are recorded in the Ussuri territory.

Raccoon dogs will eat beached fish and fish trapped in small water bodies. They rarely catch fish during the spawning season, but will eat many during the spring thaw. In their southern range, they eat young tortoises and their eggs. Insectivorous mammals hunted by raccoon dogs include shrews and hedgehogs and, on rare occasions, moles and desmans. In the Ussuri territory, large moles are their primary source of food. Plant food is highly variable, and includes bulbs, rhizomes, oats, millets, maize, nuts, fruits, berries, grapes, melons, watermelons, pumpkins and tomatoes. In Japan, they have been observed to climb trees to forage for fruits and berries, using their curved claws to climb.

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.Raccoon dogs are typically hunted from November until the snow deepens. In the Far East, they are hunted at night using Laikas and mongrels. In the 19th century, the Goldi and Oroch people would fasten bells to the collars of their raccoon dog hounds. In their introduced range, raccoon dogs are usually caught incidentally during hunts for other species. Hunting with dogs is the most efficient method in raccoon dog harvests, having success rates of 80–90%, as opposed to 8–10% with guns and 5–7% with traps. Unless they retreat in their burrows, hunted raccoon dogs can be quickly strangled by hunting dogs. Traps are usually set at their burrows, along the shores of water bodies and around marshes and ponds.

In Finland, 60,000–70,000 raccoon dogs were bagged in 2000, but the take was 170,000 in 2009 and 164,000 in 2010. Hunting of raccoon dogs in Hungary began in 1997, with an annual catch of one to 9 animals. In Poland, 6,200 were shot in 2002–03. Annual Swedish and Danish raccoon dog hunts usually result in the capture of two to seven individuals. Between 18,000 and 70,000 Japanese raccoon dogs were killed in Japan from the post-WWII period to 1982. Japan has intensified its raccoon dog culling since the 1970s, averaging 4,529 kills annually between 1990 and 1998. Harvests have since decreased.

Predators

Wolves are the main predators of raccoon dogs, killing large numbers of them in spring and summer, though attacks have been reported in autumn, too. In Tatarstan, wolf predation can account for 55.6% of raccoon dog deaths, while in northwestern Russia, it amounts to 64%. Red foxes will kill raccoon dog pups, and have been known to bite adults to death.

Both foxes and Eurasian badgers compete with raccoon dogs for food, and have been known to kill them if raccoon dogs enter their burrows. Eurasian lynxes rarely attack them. Birds of prey known to take raccoon dogs include golden eagles, white-tailed eagles, goshawks and eagle owls.