Water deer

The water deer (Hydropotes inermis) is a small deer superficially more similar to a musk deer than a true deer. Native to China and Korea, there are two subspecies: the Chinese water deer (Hydropotes inermis inermis) and the Korean water deer (Hydropotes inermis argyropus). Despite certain 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 its own subfamily (Hydropotinae).[2] However, studies of mitochondrial control region and cytochrome b DNA sequences placed it near Capreolus within an Old World section of the subfamily Capreolinae.[3][4] 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. The species is listed as vulnerable by the IUCN. It was first described to the Western world by Robert Swinhoe in 1870.

Water deer
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Cervidae
Subfamily: Hydropotinae
Genus: Hydropotes
R. Swinhoe, 1870
Species:
H. inermis
Binomial name
Hydropotes inermis
(R. Swinhoe, 1870)

Etymology
  • The genus name Hydropotes derives from the two ancient Greek words ὕδωρ (húdōr), meaning "water", and ποτής (potḗs), meaning "the fact of drinking",[5][6] 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—,[7] and refers to the fact that the water deer is antlerless.

Habitat and distribution
Korean water deer

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. 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 the southern and western China.[8] Since 2006, water deer has been reintroduced in Shanghai, with population increased from 21 individuals in 2007 to 227~299 individuals in 2013.[9] 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. Chinese water deer are now located in United Kingdom, France and Argentina, and even some in the United States.[10][11]

South Korea

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 are currently in operation this winter.[12][13]

1971 1990 1999 2005 2010 2011 2012 2013 2014 2015 2016 2017
Density per 100 ha (1 km2) of individuals[14] 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)[15] 11,269 29,756 50,333 58,786 88,041 113,763
Deer kill (hunting)[16] 1,500 13,904 3,943 10,944 14,982
Deer kill (car accidents)[17] 60,000

Britain
Chinese water deer (Hydropotes inermis inermis) at the Whipsnade Zoo

Chinese water deer were first introduced into Great Britain in the 1870s. The animals were kept in the London Zoo until 1896, when Herbrand Russell oversaw their transferral 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.

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.

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.[18]

France

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 1974. 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.[19]

Morphology

Physical attributes
The skeleton of a water deer at the Royal Veterinary College.
Body length Shoulder height Tail length Weight
77.5–100 cm[20] 42–65 cm[21] 6-7.5 cm[20] 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. In the groin of each leg is an inguinal gland used for scent marking;[22] 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.

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.

Teeth
A stuffed specimen of H. inermis at the National Museum of Nature and Science, Tokyo, Japan.

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.[23]

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.

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".[24]

Behaviour

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.

Communication

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.

Reproduction
Gestation period Young per birth Sexual maturity Life span
170–210 days[20] 1–7 Does: 7–8 months[20] 10–12 years[20]
Commonly 2–5 Bucks: 5–6 months[20]

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. 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.

See also

References
  1. Harris, R.B. & Duckworth, J.W. (2008). "Hydropotes inermis". IUCN Red List of Threatened Species. 2008. Retrieved 8 April 2009. Database entry includes a brief justification of why this species is of vulnerable.
  2. Grubb, P. (2005). "Order Artiodactyla". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 671. ISBN 978-0-8018-8221-0. OCLC 62265494.
  3. Douzery, E.; Randi, E. (November 1997). "The mitochondrial control region of Cervidae: evolutionary patterns and phylogenetic content". Molecular Biology and Evolution. 14 (11): 1154–1166. doi:10.1093/oxfordjournals.molbev.a025725. ISSN 0737-4038. PMID 9364773.
  4. Randi, E.; Mucci, N.; Pierpaoli, M.; Douzery, E. (1998). "New phylogenetic perspectives on the Cervidae (Artiodactyla) are provided by the mitochondrial cytochrome b gene". Proceedings of the Royal Society B: Biological Sciences. 265 (1398): 793–801. doi:10.1098/rspb.1998.0362. PMC 1689037. PMID 9628037.
  5. Bailly, Anatole (1 January 1981). Abrégé du dictionnaire grec français. Paris: Hachette. ISBN 2010035283. OCLC 461974285.
  6. Bailly, Anatole. "Greek-french dictionary online". www.tabularium.be. Retrieved 31 December 2017.
  7. Gaffiot, Félix (1934). Dictionnaire illustré Latin-Français (in French). Paris: Librairie Hachette. p. 810. Retrieved 31 December 2017.
  8. "Hydropotes inermis (Water Deer)". IUCN Red List of Threatened Species. 17 November 2014. 17 November 2014. Retrieved 4 June 2018.
  9. "The efforts to re-establish the Chinese water deer population in Shanghai, China". Retrieved 19 September 2019.
  10. "Archived copy". Archived from the original on 5 November 2014. Retrieved 4 November 2014.CS1 maint: archived copy as title (link)
  11. "European Mammals - Non native and Introduced Species". Hows.org.uk. Retrieved 4 June 2018.
  12. "국제 멸종위기종 고라니, 국내선 왜 민폐동물 됐을까". news.joins.com. 22 January 2018. Retrieved 3 July 2018.
  13. "17만 마리씩 죽는 고라니…어쩌다 '민폐 동물'이 됐나". news.joins.com. 21 January 2018. Retrieved 3 July 2018.
  14. "2017 Wildlife Survey" (PDF). me.go.kr. 9 October 2017. Retrieved 3 July 2018.
  15. "'농가피해' 야생동물 포획 급증…"사체 처리는 제각각"". yonhapnews.co.kr. 9 October 2017. Retrieved 3 July 2018.
  16. "야생동물 포획수 정리". 4 March 2018. Retrieved 8 December 2018.
  17. "차로 치고 새끼 유괴하고…고라니의 잔인한 봄". ecotopia.hani.co.kr. 6 May 2016. Retrieved 3 July 2018.
  18. "Deer distribution Chinese water deer 2000—2007" (PDF). bds.org.uk. Retrieved 19 December 2010.
  19. 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. ISBN 978-0-521-76061-4.
  20. "Hydropotes inermis (Chinese water deer)". Animal Diversity Web. Retrieved 27 August 2019.
  21. "Species – Chinese Water Deer". The Mammal Society. Retrieved 20 October 2020.
  22. Sun, Lixing, Bing Xiao, and Nianhua Dai. "Scent marking behaviour in the male Chinese water deer." Acta theriologica 39.2 (1994): 177-184.
  23. Geist, Valerius (30 June 2013). "Chinese water deer | mammal". Britannica.com. Retrieved 4 June 2018.
  24. Liz Langley (25 December 2014). "Krampus's Sidekick? Fanged "Vampire Deer" Explained". National Geographic. Retrieved 8 April 2016.
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