Water deer

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

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 its lack of antlers and certain other anatomical anomalies—including a pair of prominent tusks (downward-pointing canine teeth), it is classified as a cervid. Its unique anatomical characteristics have caused it to be classified in its own genus (Hydropotes) as well as its own subfamily (Hydropotinae).[2] However, a study of mitochondrial cytochrome b sequences placed it near Capreolus within an Old World section of the subfamily Capreolinae.[3] Its prominent tusks (elongated canines), similar to those of musk deer, have led to both being colloquially named vampire deer in English-speaking areas to which they have been imported. The species is listed as Vulnerable by the IUCN.

Habitat and distribution

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. They 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.[4][5]

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 in excess of 250.

The majority of the current population of Chinese water deer in Britain derives from escapees, with the remainder being descended from a number of 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.[6]

France

There are currently small, highly localized feral populations.[7]

United States

The species is not native, but a few small deer farms in the southeastern United States have successfully bred water deer.

Physical attributes

The skeleton of a Water deer at the Royal Veterinary College.
Body Length Shoulder Height Tail Length Weight
75–100 cm 45–55 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, graceful 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; 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 in color, 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 / 2.1 in. on average to as long as 8 cm / 3.2 in. Does, in comparison, have tiny canines that are on an average of 0.5 cm / 0.2 in. in length.[8]

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 movement 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."[9]

Behavior

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 a number of sounds. The main call is a bark, and this has more of a growl 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 at 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
180–210 days 1-7 Does: 7–8 months 10–12 years
Commonly 2-5 Bucks: 5–6 months

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 own 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. In: IUCN 2008. IUCN Red List of Threatened Species. 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. 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. ↑ 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. doi:10.1098/rspb.1998.0362.
  4. ↑ http://prezi.com/w7oqdthnkkll/hydropotes-inermis/
  5. ↑ http://www.hows.org.uk/inter/birds/exotics/emam.htm
  6. ↑ "Deer distribution Chinese water deer 2000—2007" (PDF). bds.org.uk. Retrieved 19 December 2010.
  7. ↑ "Los Angeles Zoo and botanical Gardens - Chinese Water Deer". Greater Los Angeles Zoo Association. Retrieved 22 November 2013.
  8. ↑ http://www.britannica.com/EBchecked/topic/112801/Chinese-water-deer
  9. ↑ Paine DE (2012-04-28). "World’s deadliest golf course boasts land mines, vampire deer". Dateline Zero. Retrieved 2012-05-27.

Further reading

External links

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