Nyctereutes Procyonoides

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in biology, Vulpes Praeglacialis (Alias:common raccoon dog or Asian raccoon dog)  is a mammal in the family Canidae and the genus Raccoon Dog. Body length 45-66 cm; tail length 16-22 cm; weight 3-6 kg. The body is short and fat, between raccoons and dogs, smaller than dogs and foxes. Body color dark brown. The snout is white; the limbs are short and black; the tail is thick and short; there is a black "pirate-like mask" on the face.

Inhabits open areas in broad-leaved forests, close to water sources or open meadows, dense shrubbery and reed fields; rarely seen in dense forests in high mountains. Live in pairs or temporary family groups. It is nocturnal and forages along river banks, lakes and seashores. It eats a wide range of foods, ranging from birds, small mammals to fruits. She is better at climbing trees and can swim. The raccoon dog is also the only canine animal that hibernates during the winter and feeds heavily in the fall until its weight increases by 50%.

The raccoon dog is an animal endemic to East Asia. It is native to Russia and Asia's North Korea, Japan, China, Mongolia and other countries. It was introduced to northern and eastern Europe between 1927 and 1957. After the raccoon dog was introduced to Europe, it spread rapidly in some areas. It is more numerous in Japan and has become extinct in some places in China. It has been included in China's "List of National Key Protected Wild Animals" and rated as a second-level protected animal.

The raccoon dog is a very ancient species of the canidae family and is considered to be a species similar to the ancestor of the canine family. There are six recognized subspecies: koreensis, orestes, procyonoides, ussuriensis and viverrinus. It has been suggested that the Japanese subspecies (viverrinus) should be classified as an independent species "Nyctereutes viverrinus" (Japanese raccoon dog), which includes two subspecies, namely "N. v. viverrinus" and “Japanese raccoon dog white subspecies” (N. v. albus Sang-In et al. 2015). The classification is based on chromosomal, molecular, and morphological differences between Japanese and mainland populations.

Common 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.

Reflecting their omnivorous diets, common raccoon dogs have small and weak canines and carnassials, flat molars, and relatively long intestines – (1.5–2.0 times longer than other canids). They have long torsos and short legs. Total lengths can range from 45 to 71 cm (18 to 28 in). The tail, at 12 to 18 cm (4.7 to 7.1 in) long, is short, amounting to less than a third 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 (6.6 lb), while in August to early September males average 6.5–7 kg (14–15 lb), with some individuals attaining a maximal weight of 9–10 kg (20–22 lb). 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 millimetres (4.7 in) in length. The winter fur protects common raccoon dogs from low temperatures ranging down to −20 to −25 °C (−4 to −13 °F). 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, whiskery hairs. The summer fur is brighter and reddish straw-coloured.

A rare white colour type occurs in China. They can also come in a yellow colour.

Raccoon dogs live in plains, hills, and some mountains in the subtropical and subtropical regions. They often inhabit sparse weed forests on embankments, riverbanks, and open fields near water sources. The northernmost area of distribution is between 65° north latitude and the Arctic Circle (where the annual average temperature is slightly above 0°C, the snow cover is less than 800 mm, the snow cover duration is less than 175 days, and the growing season is more than 135 days). As the global climate warms, raccoon dogs are constantly expanding their activity range, which has expanded north to between 67° north latitude and the Arctic Circle, and south to southeastern Spain.

The habitat has two typical characteristics: first, raccoon dogs often appear near water; second, in autumn, raccoon dogs rely more or less on fruits and berries, which will affect their habitat selection. In Japan, their habitats include deciduous forests, evergreen broadleaf forests, mixed forests, farmland, and urban areas ranging from coastal to subalpine zones. In rural areas, the species prefers herbaceous habitats and uses fewer cedar plantations throughout the year, often using riparian areas. In urban areas, raccoon dogs inhabit areas with as little as 5% forest cover. In the Russian Far East, raccoon dogs prefer open fields, especially moist meadows and farmland, and avoid shady forests.

Within their introduced range, raccoon dogs prefer moist grasslands and other habitats with rich shrubland, mixed forests, and river and lake shores, especially in early summer. In late summer and fall, raccoon dogs prefer moist heaths and abundant berries. However, in the Finnish archipelago, raccoon dogs live in barren pine forests and feed on the fruits of cyanobacteria. In Finland, generally the raccoon dog's favorite habitats are plots of land with rich shrubland, moist forests, moist meadows, gardens and agricultural areas. It is indeed rare in large coniferous forests.

cluster

Raccoon dogs live in groups or alone. Generally, groups form family units, with pairs living in burrows, adult male raccoon dogs, female raccoon dogs and juvenile raccoon dogs living in the same burrow, and some even cohabiting with juvenile raccoon dogs in other burrows.

Behavior

Social: Raccoon dogs are relatively docile and timid, and generally do not attack each other actively. They will only attack when disturbed or feel threatened. Although raccoon dogs are canines, they do not bark like dogs. They bark low and make "woo" and "meow" sounds to express friendliness; when they growl, they are aggressive. In addition, they communicate through the smell of urine and feces.

Burrowing: They like to live in caves, but they often use abandoned holes of other animals as nests instead of digging them themselves.

Activities: Raccoon dogs are nocturnal animals. They usually sleep in burrows during the day and go out for activities at night. They often bend their waists. They are not fast or flexible, but they can climb high and climb trees. Raccoon dogs generally move within an area of 5-10 square kilometers away from home. They have a fixed excretion place and are accustomed to traveling in a straight line. They often walk randomly around the entrance of the cave, causing confusing footprints to confuse the hunter's vision.

Hibernation: Raccoon dogs that live in higher latitudes in the north have the habit of hibernating in winter, but this hibernation is different from true hibernation. They will occasionally come out to be active when the weather is warmer. This phenomenon is unique to raccoon dogs among canines. The hibernation period is from the end of November to the beginning of August of the following year.

feeding habits

Forage along river banks, lakes and seashores. Raccoon dogs have a mixed diet and mainly feed on various small rodents. They also often prey on fish, frogs, crabs, etc. by the stream. In addition, they also eat plant foods such as fruits, grains, vegetables, etc. Raccoon dogs are more dependent on plants than most other canids, preferring to forage in fern-rich woodlands, eating roots, stems, leaves, buds, berries, seeds and nuts.

world

Origin: China, Japan, North Korea, South Korea, Mongolia, Russia (Primorsky Krai, Amur River, Chita, Khabarovsk).

Introduction: Belgium, Bosnia and Herzegovina, Bulgaria, Austria, Belarus, Czech Republic, Estonia, Finland, France, Germany, Russia (European zone), Slovakia and Sweden.

Uncertain origin: Uzbekistan.

China

In China, raccoon dogs are mainly distributed in Heilongjiang, Jilin, Liaoning, Hebei, Shanxi, Jiangsu, Yunnan, Hunan, Anhui, Sichuan, Zhejiang, Fujian, Jiangxi, Guangdong and Guangxi.

The species' native range extends from northern Indochina (south to northeastern Vietnam, east of the Red River, and southern Yunnan Province in China) through the eastern provinces of China and the Korean Peninsula to the tip of southeastern Russia and Mongolia. In the Japanese archipelago, the species is found in Hokkaido, Honshu, Shikoku, Kyushu, Awaji Island, Sado Island, and other small islands of Japan south of Kyushu (such as the Okinawa Islands, Nansei Islands, Miyako Islands, and Ogasawara Islands). Introducing Yakushima. Does not exist in Hainan, China and Taiwan.

Reproduction and development

The mating season begins from early February to late April, depending on location. Common 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 at dawn, and typically will last 6–9 minutes. Estrus lasts from a few hours to six days, during which females may mate up to five times. Females 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 typically consist of 6–8 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 common raccoon dog's now-extensive introduced European range.

At birth, pups weigh 60–110 g (2.1–3.9 oz), 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 begin eating food brought to them as early as the age of three weeks to one month. They reach their full size at the age of 4.5 months. Pups leave their parents in late August–September. By October, the pups, which by then resemble adults, 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.

Hibernation

Common 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, common raccoon dogs hibernate only during severe snowstorms. In December, their physical activity decreases once snow depth reaches 15–20 cm (5.9–7.9 in), and limit the range from their burrows to no more than 150–200 m (490–660 ft). Their daily activities increase during February when the females become receptive, and when food is more available.

Vocalizations

Like foxes, they do not bark, uttering instead a growl, followed by a long-drawn, melancholy whine. Captive specimens have been known to utter daily a very different kind of sound when hungry, described as a sort of mewing plaint. Males fighting for females may yelp and growl.

There is no information on abundance in its native range outside of Japan, where the species is common. In 2010, raccoon dogs may still exist in the wild in parts of Guangxi and Guangdong in China, but may be threatened elsewhere. Abundance estimates have never been conducted in Japan, but indirect indices (e.g., number of raccoon dogs killed per kilometer of roadway on national highways and harvest density per prefecture) suggest that relative abundance is higher in southwestern Japan (i.e., Kyushu and Shikoku). High, lower in Hokkaido, central and extreme urban areas. There is very little information on their status in Vietnam, the southernmost part of their range. A 2004 survey in five districts in Na Hang District, Tuyen Quang Province recorded the presence of two small animals in captivity in Na Vang village, apparently taken from a small cave (presumably a nest) in Long Noi district (Le Trong Trai et al. 2004), but otherwise there is no other recent information.

Raccoon dogs were introduced to Europe in the early 20th century and were bred as fur animals in Russia and kept as pets in the UK. In 2016, it has become an invasive species in France, the Netherlands, Sweden, Finland, Germany and Poland, causing harm to the natural ecology. In order to control the wild population, Sweden has banned the breeding of raccoon dogs and is trying to completely cull the wild population.

The species is common in introduced areas; in Finland, for example, the adult population consists of 110,000-120,000 individuals (160,000-170,000 individuals per year). The autumn population, including the year's young raccoon dogs, is approximately 320,000.