|Genus:|| Hydropotes |
R. Swinhoe, 1870
(R. Swinhoe, 1870)
|Range of Water Deer|
The water deer (Hydropotes inermis) is a small deer species native to China and Korea. Its prominent tusks, similar to those of musk deer, have led to both subspecies being colloquially named vampire deer in English-speaking areas to which they have been imported. It was first described to the Western world by Robert Swinhoe in 1870. 
There are two subspecies: the Chinese water deer (H. i. inermis) and the Korean water deer (H. i. argyropus). The water deer is superficially more similar to a musk deer than a true deer; despite anatomical peculiarities, including a pair of prominent tusks (downward-pointing canine teeth), and its lack of antlers, it is classified as a cervid. Yet, its unique anatomical characteristics have caused it to be classified in its own genus (Hydropotes) as well as historically its own subfamily (Hydropotinae).  However, studies of mitochondrial control region and cytochrome b DNA sequences placed it near Capreolus within an Old World section of the subfamily Capreolinae,   and all later molecular analysis show that Hydropotes is a sister taxon of Capreolus.     
The genus name Hydropotes derives from the two ancient Greek words ὕδωρ (húdōr), meaning "water", and πότης (potḗs), meaning "drinker",   and refers to the preference of this cervid for rivers and swamps.
The etymology of the species name corresponds to the Latin word inermis meaning unarmed, defenceless—itself constructed from the prefix in- meaning without and the stem arma meaning defensive arms, armor—,  and refers to the water deer's lack of antlers.
Archeological studies indicate water deer was once distributed among much broader range than currently during the Pleistocene and the Holocene periods; records have been obtained from eastern Tibet in west, Inner Mongolia and northeastern China in north, southeastern Korean Peninsula (Holocene) and Japanese archipelago (Pleistocene) in east, southern China and northern Vietnam in south.  Water deer also inhabited Taiwan historically, however this population presumably became extinct as late as the early 19th century. 
Water deer are indigenous to the lower reaches of the Yangtze River, coastal Jiangsu province (Yancheng Coastal Wetlands), and islands of Zhejiang of east-central China, and in Korea, where the demilitarized zone has provided a protected habitat for a large number. The Korean water deer (Hydropotes inermis argyropus) is one of the two subspecies of water deer. While the population of Chinese subspecies is critically endangered in China, the Korean subspecies are known to inhabit 700,000 throughout South Korea.  In China, water deer are found in Zhoushan Islands in the Zhejiang (600~800), Jiangsu (500~1,000), Hubei, Henan, Anhui (500), Guangdong, Fujian, Poyang Lake in Jiangxi (1,000), Shanghai, and Guangxi. They are now extinct in southern and western China.  Since 2006, water deer has been reintroduced in Shanghai, with population increased from 21 individuals in 2007 to 227~299 individuals in 2013.  In Korea, water deer are found nationwide and are known as gorani (고라니). 
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 the United Kingdom and another was extirpated from France.  
Despite a listing of 'vulnerable' by the International Union for Conservation of Nature (IUCN), in South Korea, the animal is thriving due to the extinction of natural predators such as Korean tigers and leopards. Since 1994, Korean water deer have been designated as "harmful wildlife", a term given by the Ministry of Environment to wild creatures that can cause harm to humans or their property. Currently, certain local governments offer bounties from 30,000 won($30) to 50,000 won($50) during the farming season. However, the hunting of water deer is not restricted to the warm season, as 18 hunting grounds were currently in operation in the winter of 2018.  
|Density per 100 ha (1 km2) of individuals ||0.4||3.7||5.3||6.2||6.6||7.3||7.5||6.9||8.2||7.8||8.0||8.3|
|Deer kill (bounty hunting) ||11,269||29,756||50,333||58,786||88,041||113,763|
|Deer kill (hunting) ||1,500||13,904||3,943||10,944||14,982|
|Deer kill (car accidents) ||60,000|
Chinese water deer were first introduced into Great Britain in the 1870s. The animals were kept in the London Zoo until 1896, when the Duke of Bedford oversaw their transfer to Woburn 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 to Whipsnade, also in Bedfordshire, and released into the park. The current population of Chinese water deer at Whipsnade is currently 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. It appears that the deer's 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 into Cambridgeshire, Norfolk, Suffolk and North Essex, and south towards Whipsnade. There have been small colonies 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 noted the Chinese water deer as "notably increasing its range" since the last census in 2000. 
A small population existed in France originating from animals that had escaped an enclosure in 1960 in western France (Haute-Vienne, near Poitiers). 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, there have been no sightings since 2000, and the population is assumed to be extinct. 
On April 1, 2019, a water deer was spotted using a photo trap in the "Land of the Leopard" national park in the Khasan district of Primorsky 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 reindeer became the new, 327th, mammal species in the fauna of Russia. 
|Body length||Shoulder height||Tail length||Weight|
|77.5–100 cm ||42–65 cm ||6-7.5 cm ||9–14 kg|
|2.5-3.3 ft||18-22 in||2.4-3 in||20-31 lbs|
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 an inguinal gland used for scent marking;  this deer is the only member of the Cervidae to possess such glands. The short tail is no more than 5–10 cm / 1.9–3.8 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 upper torso.[ 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. 
The teeth usually erupt in the autumn of the deer's first year at approximately 6–7 months of age. By early spring, the recently erupted tusks reach approximately 50% of their final length. As the tusks develop, the root remains open until the deer is about eighteen months to two years old. When fully grown, only about 60% of the tusk 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. It is due to these teeth that this animal is often referred to as a "vampire deer". 
The mitochondrial DNA of samples from the native Chinese population and the introduced UK population was analysed to infer each population's genetic structure and genetic diversity. It was found that the UK population displays lower levels of genetic diversity, and that there is genetic differentiation between the native and introduced population.  It was also found that the source population of the British deer is likely to be extinct.  This has implications for the conservation of the different populations, especially as Hydropotes inermis is classified as Vulnerable in its native range according to the IUCN Red List.
Apart from mating during the rutting season, water deer are solitary animals, and males are highly territorial. Each buck marks 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 his preorbital glands against it. Males may also bite off vegetation to delineate territorial boundaries. 
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 (32–64 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. 
Females do not seem to be territorial 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, and this has more of a growling tone when compared with the sharper yap of a muntjac. The bark is used as an alarm, and water deer will bark repeatedly at people and each other for reasons unknown. If challenged during the rut, a buck will emit a clicking sound. It is uncertain how this unique sound is generated, although it is possibly by using its molar teeth. During the rut, a buck following a doe will make a weak whistle or squeak. The does emit a soft pheep to call to their fawns, whilst an injured deer will emit a screaming wail.
|Gestation period||Young per birth||Sexual maturity||Life span|
|170–210 days ||1–7 (commonly 2–5)||7–8 months (does); 5–6 months (bucks) ||10–12 years |
During the annual rut in November and December, the male will seek out and follow females, giving soft squeaking contact calls and checking for signs of estrus 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 is polygynous, with most females being mated inside the buck's territory. After repeated mountings, copulation is brief. 
Water deer have been known to produce up to seven young, but two to 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 concealing vegetation, where they will 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 existence. Young water deer are also known to grow faster and be more precocious in comparison to other similar species. 
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including muntjac, elk (wapiti), red deer, and fallow deer; and the Capreolinae, including reindeer (caribou), white-tailed deer, roe deer, and moose. Male deer of all species, as well as female reindeer, grow and shed new antlers each year. In this, they differ from permanently horned antelope, which are part of a different family (Bovidae) within the same order of even-toed ungulates (Artiodactyla).
Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on males, with the exception of reindeer/caribou. Antlers are shed and regrown each year and function primarily as objects of sexual attraction and as weapons.
Musk deer can refer to any one, or all seven, of the species that make up Moschus, the only extant genus of the family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, but rather their family is closely related to Bovidae, the group that contains antelopes, bovines, sheep, and goats. The musk deer family differs from cervids, or true deer, by lacking antlers and preorbital glands also, possessing only a single pair of teats, a gallbladder, a caudal gland, a pair of canine tusks and—of particular economic importance to humans—a musk gland.
The North Sulawesi babirusa is a pig-like animal native to Sulawesi and some nearby islands in Indonesia. It has two pairs of large tusks composed of enlarged canine teeth. The upper canines penetrate the top of the snout, curving back toward the forehead. The North Sulawesi babirusa is threatened from hunting and deforestation.
The sika deer, also known as the Northernspotted deer or the Japanese deer, is a species of deer native to much of East Asia and introduced to other parts of the world. Previously found from northern Vietnam in the south to the Russian Far East in the north, it is now uncommon except in Japan, where the species is overabundant.
Muntjacs, also known as the barking deer or rib-faced deer, are small deer of the genus Muntiacus native to South Asia and Southeast Asia. Muntjacs are thought to have begun appearing 15–35 million years ago, with remains found in Miocene deposits in France, Germany and Poland. Most species are listed as Least Concern or Data Deficient by the IUCN, although others such as the black muntjac, Bornean yellow muntjac, and giant muntjac are Vulnerable, Near Threatened, and Critically Endangered, respectively.
The red deer is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of western Asia. It also inhabits the Atlas Mountains of Northern Africa; its early ancestors are thought to have crossed over to Morocco, then to Algeria, Libya and Tunisia via the Strait of Gibraltar, becoming the only species of true deer (Cervidae) to inhabit Africa. Red deer have been introduced to other areas, including Australia, New Zealand, the United States, Canada, Peru, Uruguay, Chile and Argentina. In many parts of the world, the meat (venison) from red deer is used as a food source.
The chital or cheetal, also known as the spotted deer, chital deer, and axis deer, is a deer species native to the Indian subcontinent. It was first described and given a binomial name by German naturalist Johann Christian Polycarp Erxleben in 1777. A moderate-sized deer, male chital reach 90 cm (35 in) and females 70 cm (28 in) at the shoulder. While males weigh 70–90 kg (150–200 lb), females weigh around 40–60 kg (88–132 lb). It is sexually dimorphic; males are larger than females, and antlers are present only on males. The upper parts are golden to rufous, completely covered in white spots. The abdomen, rump, throat, insides of legs, ears, and tail are all white. The antlers, three-pronged, are nearly 1 m long.
The Southern red muntjac is a deer species native to Southeast Asia. It is formely known as the Indian muntjac or the common muntjac before the species was taxonomically revised to represent only populations of Sunda and perhaps Malaysia. The other populations being attributed to this species are now attributed to Muntiacus vaginalis. Muntjacs are also referred to as barking deer. It is listed as Least Concern on the IUCN Red List.
The tufted deer is a small species of deer characterized by a prominent tuft of black hair on its forehead and fang-like canines for the males. It is a close relative of the muntjac, living somewhat further north over a wide area of central China and northeastern Myanmar. Suffering from overhunting and habitat loss, this deer is considered near-threatened. It is the only member of the genus Elaphodus.
Reeves's muntjac, also known as the Chinese muntjac, is a muntjac species found widely in southeastern China and Taiwan. It has also been introduced in the United Kingdom, Ireland, the Netherlands, Belgium, and Japan. It takes its name from John Reeves, a naturalist employed by the British East India Company in the 19th century.
Thorold's deer is a threatened species of deer found in grassland, shrubland, and forest at high altitudes in the eastern Tibetan Plateau. It is also known as the white-lipped deer for the white patches around its muzzle.
The Philippine mouse-deer, also known as the Balabac chevrotain or pilandok, is a small, nocturnal ruminant, which is endemic to Balabac and nearby smaller islands southwest of Palawan in the Philippines. The genus Tragulus means 'little goat' and the Philippine mouse-deer has been named so due to the horizontal pupils of the eyes. This position of the pupil allows for an increase in peripheral depth perception. It has traditionally been considered a subspecies of the greater mouse-deer. In 2004, though, T. nigricans was separated from T. napu as its own species due to differences in skull morphology. Contrary to its common name, the Philippine mouse-deer does not belong to the true deer family (Cervidae), but is rather more closely connected to antelope and antelope-like bovids; it is a member of the chevrotain family, a grouping of some of the world's smallest hoofed mammals.
The black musk deer or dusky musk deer is a species of even-toed ungulate in the family Moschidae. It is found in Bhutan, China, India, Myanmar, and Nepal.
The Capreolinae, Odocoileinae, or the New World deer are a subfamily of deer. Alternatively, they are known as the telemetacarpal deer, due to their bone structure being different from the plesiometacarpal deer subfamily Cervinae. The telemetacarpal deer maintain their distal lateral metacarpals, while the plesiometacarpal deer maintain only their proximal lateral metacarpals. The Capreolinae are believed to have originated in the Middle Miocene, between 7.7 and 11.5 million years ago, in Central Asia.
Rucervus is a genus of deer from India, Nepal, Indochina, and the Chinese island of Hainan. The only extant representatives, the barasingha or swamp deer and Eld's deer, are threatened by habitat loss and hunting; another species, Schomburgk’s deer, went extinct in 1938. Deer species found within the genus Rucervus are characterized by a specific antler structure, where the basal ramification is often supplemented with an additional small prong, and the middle tine is never present. The crown tines are inserted on the posterior side of the beam and may be bifurcated or fused into a small palmation.
Megaceroides algericus is an extinct species of deer known from the Late Pleistocene to the Holocene of North Africa. It is one of only two species of deer known to have been native to the African continent, alongside the Barbary stag, a subspecies of red deer. It is considered to be closely related to the giant deer species of Eurasia.