The twosubspecies are the Chinese water deer (H. i. inermis) and the Korean water deer (H. i. argyropus). The water deer is superficially more similar to amusk deer than atrue deer; despiteanatomical peculiarities, including a pair of prominenttusks (downward-pointingcanine teeth) and its lack ofantlers, it is classified as a cervid, yet its unique anatomical characteristics have caused it to be classified in its owngenus (Hydropotes), as well as historically its own subfamily (Hydropotinae).[3] However, studies of mitochondrialcontrol region andcytochrome b DNA sequences placed it nearCapreolus within anOld World section of the subfamilyCapreolinae,[4][5] and all later molecular analyses show thatHydropotes is a sister taxon ofCapreolus.[6][7][8][9][10]
The genus nameHydropotes derives from the twoancient Greek wordsὕδωρ (húdōr), meaning "water", andπότης (potḗs), meaning "drinker",[11][12] and refers to the preference of this cervid for rivers and swamps.[13]
The etymology of the species name corresponds to theLatin wordinermis meaning unarmed, defenceless, itself constructed from the prefixin- meaning without, and the stemarma meaning defensive arms, armour,[14] and refers to the water deer's lack of antlers.
Archeological studies indicate water deer were once distributed among much broader range than currently during thePleistocene and theHolocene periods; records have been obtained from easternTibet in the west,Inner Mongolia and northeasternChina in the north, southeasternKorean Peninsula (Holocene) andJapanese archipelago (Pleistocene) in the east, southern China and northernVietnam in the south.[15] Water deer also inhabitedTaiwan historically, however this population presumably became extinct as late as the early 19th century.[16]
Water deer are indigenous to the lower reaches of theYangtze River, coastalJiangsu province (Yancheng Coastal Wetlands), and islands ofZhejiang of east-central China, and in Korea, where thedemilitarized zone has provided a protected habitat for a large number. The Korean water deer (H. i. argyropus) is one of the two subspecies of water deer. While the population of Chinese subspecies is critically endangered in China, the Korean subspecies is known to number 700,000 throughout South Korea.[17] In China, water deer are found inZhoushan Islands in theZhejiang (600–800),Jiangsu (500–1,000),Hubei,Henan,Anhui (500),Guangdong,Fujian,Poyang Lake inJiangxi (1,000),Shanghai, andGuangxi. They are now extinct in southern and western China.[1] Since 2006, water deer have been reintroduced in Shanghai, with a population increase from 21 individuals in 2007 to 227–299 individuals in 2013.[18] In Korea, water deer are found nationwide and are known asgorani (고라니).[19]
Water deer inhabit the land alongside rivers, where they are protected from sight by the tall reeds and rushes. They are also seen on mountains,swamps,grasslands, and even open cultivated fields. Water deer are proficient swimmers, and can swim several miles to reach remote river islands. An introduced population of Chinese water deer exists in theUnited Kingdom and another was extirpated fromFrance.[20][21]
Despite a listing of "vulnerable" by the International Union for Conservation of Nature in South Korea, the animal is thriving because of the extinction of natural predators, such asKorean tigers andleopards. Since 1994, Korean water deer have been designated as "harmful wildlife", a term given by theMinistry of Environment to wild creatures that can cause harm to humans or their property. Currently, certain local governments offer bounties from 30,000 to 50,000 won ($30 - 50) during the farming season. However, the hunting of water deer is not restricted to the warm season, as 18 hunting grounds were in operation in the winter of 2018.[22][23]
Chinese water deer (Hydropotes inermis inermis) at theWhipsnade Zoo
Chinese water deer were first introduced intoGreat Britain in the 1870s. The animals were kept in theLondon Zoo until 1896, whenthe Duke of Bedford oversaw their transfer toWoburn Abbey,Bedfordshire. More of the animals were imported and added to the herd over the next three decades. In 1929 and 1930, 32 deer were transferred from Woburn toWhipsnade, also in Bedfordshire, and released into the park. The current population of Chinese water deer at Whipsnade is estimated to be more than 600, while the population at Woburn is probably more than 250.[citation needed]
The majority of the current population of Chinese water deer in Britain derives from escapees, with the remainder being descended from many deliberate releases. Most of these animals still reside close to Woburn Abbey. The deer's apparent strong preference for a particular habitat – tall reed and grass areas in rich alluvial deltas - has restricted its potential to colonize further afield. The main area of distribution is from Woburn east intoCambridgeshire,Norfolk,Suffolk, and NorthEssex, and south towards Whipsnade. Small colonies have been reported in other areas.[citation needed] The British Deer Society coordinated a survey of wild deer in the United Kingdom between 2005 and 2007 and identified the Chinese water deer as "notably increasing its range" since the previous census in 2000.[27]
A small population existed in France originating from animals that had escaped an enclosure in 1960 in western France (Haute-Vienne, nearPoitiers). The population was reinforced in 1965 and 1970 and the species has been protected since 1973. Despite efforts to locate the animals with the help of local hunters, no sightings have occurred since 2000, and the population is assumed to be extinct.[28]
On April 1, 2019, a water deer was spotted using aphoto trap in the"Land of the Leopard" national park in theKhasan district ofPrimorsky Krai, Russia, 4.5 km from the border with China. In 2022, the population of water deer in Primorsky Krai was about 170 individuals. Thus, the water deer became the newest, and 327th, mammal species to be listed among thefauna of Russia.[29]
The water deer has narrow pectoral and pelvic girdles, long legs, and a long neck. The powerful hind legs are longer than the front legs so that the haunches are carried higher than the shoulders. They run with rabbit-like jumps.[citation needed] In the groin of each leg is angland used for scent marking;[32] this deer is the only member of the Cervidae to possess such glands. The short tail is no more than 5–10 cm (2.0–3.9 in) in length and is almost invisible, except when it is held raised by the male during the rut. The ears are short and very rounded, and both sexes lack antlers.[citation needed]
The coat is an overall golden-brown color and may be interspersed with black hairs, while the undersides are white. The strongly tapered face is reddish-brown or gray, and the chin and upper throat are cream-colored. The hair is longest on the flanks and rump. In the fall, the summer coat is gradually replaced by a thicker, coarse-haired winter coat that varies from light brown to grayish brown. Neither the head nor the tail poles are well differentiated as in gregarious deer; consequently, this deer's coat is little differentiated. Young are born dark brown with white stripes and spots along their uppertorsos.[citation needed]
The water deer have developed long canine teeth which protrude from the upper jaw like the canines of musk deer. The canines are fairly large in the bucks, ranging in length from 5.5 cm (2.2 in) on average to as long as 8 cm (3.1 in). Does, in comparison, have tiny canines that are an average of 0.5 cm (0.2 in) in length.[33]
The teeth usually erupt in theautumn of the deer's first year around 6–7 months of age. By early spring, the recently erupted tusks reach about 50% of their final length. As the tusks develop, the root remains open until the deer is about 18 to 24 months old. When fully grown, only about 60% of thetusk is visible below the gum.[citation needed]
These canines are held loosely in their sockets, with their movements controlled by facial muscles. The buck can draw them backwards out of the way when eating. In aggressive encounters, he thrusts his canines out and draws in his lower lip to pull his teeth closer together. He then presents an impressive, two-pronged weapon to rival males. Due to these teeth, this animal is sometimes referred to as a "vampire deer".[34]
Themitochondrial DNA of samples from the native Chinese population and the introduced UK population were analysed to infer each population's genetic structure andgenetic diversity. The UK population was found to display lower levels of genetic diversity, and genetic differentiation exists between the native and introduced populations.[35] The source population of the British deer was found to be likelyextinct.[35] This has implications for the conservation of the different populations, especially asH. inermis is classified asvulnerable in its native range according to theIUCN Red List.
Apart from mating during therutting season, water deer are solitary animals, and males are highlyterritorial. Each buckmarks out his territory with urine and feces. Sometimes a small pit is dug and it is possible that in digging, the male releases scent from the interdigital glands on its feet. The male also scent-marks by holding a thin tree in his mouth behind the upper canines and rubbing hispreorbital glands against it. Males may also bite off vegetation to delineate territorial boundaries.[36]
Water deer use their tusks for territorial fights and are not related to carnivores. Confrontations between males begin with the animals walking slowly and stiffly towards each other, before turning to walk in parallel 10–20 m (33–66 ft) apart, to assess one another. At this point, one male may succeed in chasing off his rival, making clicking noises during the pursuit. However, if the conflict is not resolved at the early stage, the bucks will fight. Each would try to wound the other on the head, shoulders, or back, by stabbing or tearing with his upper canines. The fight is ended by the loser, who either lays his head and neck flat on the ground or turns tail and is chased out of the territory. Numerous long scars and torn ears seen on males indicate that fighting is frequent. The fights are seldom fatal but may leave the loser considerably debilitated. Tufts of hair are most commonly found on the ground in November and December, showing that encounters are heavily concentrated around the rut.[36]
Females do not seem to beterritorial outside the breeding season and can be seen in small groups, although individual deer do not appear to be associated; they will disperse separately at any sign of danger. Females show aggression towards each other immediately before and after the birth of their young and will chase other females from their birth territories.[citation needed]
Water deer are capable of emitting several sounds. The main call is a bark, which has more of a growling tone when compared with the sharper yap of amuntjac. The bark is used as an alarm, and water deer bark repeatedly at people and each other for reasons unknown. If challenged during the rut, a buck emits a clicking sound. How this unique sound is generated is unknown, although it is made possibly by using its molar teeth. During the rut, a buck following a doe makes a weak whistle or squeak. The does emit a soft "pheep" to call to their fawns, whilst an injured deer can emit a screaming wail.
During the annual rut in November and December, the male seeks out and follows females, giving soft, squeaking, contact calls and checking for signs ofestrus by lowering his neck and rotating his head with ears flapping. Scent plays an important part in courtship, with both animals sniffing each other. Mating among water deer ispolygynous, with most females being mated inside the buck's territory. After repeated mountings,copulation is brief.[37]
Water deer have been known to produce up to seven young, but two or three is normal for this species, the most prolific of all deer.[citation needed] The doe often gives birth to her spotted young in the open, but they are quickly taken to concealingvegetation, where they remain most of the time for up to a month. During these first few weeks, fawns come out to play. Once driven from the natal territory in late summer, young deer sometimes continue to associate with each other, later separating to begin their solitary existences. Young water deer are also known to grow faster and be more precocious in comparison to other similar species.[38]
^Park, H., Woo, D., Choi, T. and Hong, S., 2021. Assessment of the Behavioural Response of Korean Water Deer (Hydropotes inermis argyropus) to Different Fence Heights. [online] Available at: <https://www.mdpi.com/2076-2615/11/4/938/htm> [Accessed 26 March 2021]
^Apollonio, Marco; Andersen, Reidar; Putman, Rory, eds. (2010). "20 - Ungulates and their management in France".European ungulates and their management in the 21st century. Cambridge: Cambridge University Press. p. 448.ISBN978-0-521-76061-4.
^abRory Putman; Nicholas Dunn; Endi Zhang; Min Chen; Christian Miquel;Vincent Savolainen (2021). "Conservation genetics of native and European-introduced Chinese water deer (Hydropotes inermis)".Zoological Journal of the Linnean Society.191 (4):1181–1191.doi:10.1093/zoolinnean/zlaa076.
^abCooke, Arnold (1998).Chinese water deer. Lynne Farrell, Mammal Society, British Deer Society. Mammal Society.ISBN0-906282-38-1.OCLC59362218.
^Cooke, Arnold S. (2019).Muntjac and water deer: natural history, environmental impact and management. Exeter, UK.ISBN978-1-78427-192-3.OCLC1110122665.{{cite book}}: CS1 maint: location missing publisher (link)
^Dubost, G., Charron, F., Courcoul, A., & Rodier, A. (2011). The Chinese water deer,Hydropotes inermis — a fast-growing and productive ruminant. Mammalian Biology, 76(2), 190–195.https://doi.org/10.1016/j.mambio.2010.04.001