From Wikipedia, the free encyclopedia

Dugong[1] Fossil range: Early Eocene–Recent PreЄ Є O S D C P T J K Pg N
Conservation status
Vulnerable (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Sirenia
Family:	Dugongidae Gray, 1821
Subfamily:	Dugonginae Simpson, 1932
Genus:	Dugong Lacépède, 1799
Species:	D. dugon
Binomial name
Dugong dugon (Müller, 1776)
Natural range of D. dugon.

The dugong (Dugong dugon) is a large marine mammal which, together with the manatees, is one of four living species of the order Sirenia. It is the only living representative of the once-diverse family Dugongidae; its closest modern relative, Steller's Sea Cow (Hydrodamalis gigas), was hunted to extinction in the 18th century. It is also the only sirenian in its range, which spans the waters of at least 37 countries throughout the Indo-Pacific,^[3] though the majority of dugongs live in the northern waters of Australia between Shark Bay and Moreton Bay.^[4] The dugong is the only strictly-marine herbivorous mammal, as all species of manatee utilize fresh water to some degree.^[3]

Like all modern sirenians, the dugong has a fusiform body with no dorsal fin or hind limbs, instead possessing paddle-like forelimbs used to maneuver itself. It is easily distinguished from the manatees by its fluked, dolphin-like tail, but also possesses a unique skull and teeth.^[5] The dugong is heavily dependent on seagrasses for subsistence and is thus restricted to the coastal habitats where they grow, with the largest dugong concentrations typically occurring in wide, shallow, protected areas such as bays, mangrove channels and the lee sides of large inshore islands.^[3] Its snout is sharply downturned, an adaptation for grazing and uprooting benthic seagrasses.

The dugong has been hunted for thousands of years for its meat and oil,^[6] although dugong hunting also has great cultural significance throughout its range.^[7] The dugong's current distribution is reduced and disjunct, and many populations are close to extinction.^[3] The IUCN lists the dugong as a species vulnerable to extinction, while the Convention on International Trade in Endangered Species limits or bans the trade of derived products based on the population involved. Despite being legally protected in many countries throughout their range, the main causes of population decline remain anthropogenic and include hunting, habitat degradation, and fishing-related fatalities.^[8] With its long lifespan of 70 years or more, and slow rate of reproduction, the dugong is especially vulnerable to these types of exploitation.^[3] Dugongs are also threatened by storms, parasites, and their natural predators, sharks, killer whales, and crocodiles.^[8]

Etymology and taxonomy

The dugong was first classified by Müller in 1776 as Trichechus dugon,^[9] a member of the manatee genus previously defined by Linnaeus.^[10] It was later assigned as the type species of Dugong by Lacépède^[11] and further classified within its own family by Gray^[12] and subfamily by Simpson.^[13]

The word "dugong" derives from the Tagalog term dugong which was in turn adopted from the Malay duyung, both meaning "lady of the sea."^[14] Other common local names include "sea cow," "sea pig" and "sea camel."^[8]

Anatomy and morphology

Dugong with attached remora (Lamen Island, Epi, Vanuatu).

The dugong's body is large and fusiform, with thick, smooth skin that is a pale cream color at birth but darkens dorsally and laterally to a brownish to dark gray with age.^[15] The body is sparsely covered in short hair, a common feature among sirenians which may allow for tactile interpretation of their environment.^[16] The dugong has paddle-like forelimbs which aid in movement and feeding, while its fluked tail provides locomotion through vertical movement. The teats are located just behind the forelimbs, similar to their location in elephants. Like the Amazonian Manatee, the dugong lacks nails on its forelimbs.

Unlike the manatees, the dugong's teeth do not continually grow back via horizontal tooth replacement.^[17] The dugong has two incisors (tusks) which grow posteriorly until puberty, after which they first erupt in males. The female's tusks continue to grow posteriorly, sometimes erupting later in life after reaching the base of the premaxilla.^[6] The full dental formula of dugongs is:

Like other sirenians, the dugong experiences pachyostosis, a condition in which the ribs and other long bones are unusually solid and contain little or no marrow. These heavy bones, which are among the densest in the animal kingdom,^[18] may act as a ballast to help keep sirenians suspended slightly below the water's surface.^[19]

Dugongs are generally smaller than manatees (with the exception of the Amazonian Manatee), reaching an average adult length of 2.7 metres (8.9 ft) and weight of 150 to 300 kilograms (330 to 660 lb).^[20] An adult's length rarely exceeds 3 metres (9.8 ft), and females tend to be larger than males.^[6] The largest known dugong was a female landed off the Saurashtra coast of west India, measuring 4.03 metres (13.2 ft) and weighing 1,018 kilograms (2,240 lb).^[21]

Distribution

Typical dugong Feeding area in Moreton Bay

Dugong on the sea floor at Marsa Alam, Egypt

Remaining populations of dugong are greatly reduced, although they once covered all of the tropical South Pacific and Indian Oceans.^{[citation needed]} Their historic range is believed to correspond to that of certain seagrasses.^[3] Groups of 10,000 or more are present on the Great Barrier Reef of Australia, at Shark Bay, and in Torres Strait south of New Guinea. Before 1970, it is thought, large populations were also present in coastal Mozambique and Kenya, but these have dwindled. Palau also has a small population. On January 22, 2003, an individual was found (weight 300 kg, length 2 m) off the coast of Tanzania.^{[citation needed]}

Moreton Bay in Brisbane, Australia, is one of many homes to the dugong because it contains clean, clear water at the appropriate depth ranges; suitable food; and access to the sea for warmth. Although strong tidal currents affect the exact times and durations of each visit to the bay, the dugong return for protection from large sharks. Important to the future of the dugong, the area is a 200 km stretch of high-density human habitation and recreation, with easy access to study and learn how to best protect the remaining herds.

A small number of dugongs are also found in the Straits of Johor (which separates Johor in Malaysia and Singapore), in the Philippine provinces of Palawan, Romblon, Guimaras and Davao Oriental, in the Arabian Sea along Pakistan and in the Red Sea in Egypt provinces Marsa Alam at Marsa Abu Dabbab. The remaining dugongs in the Persian Gulf have reportedly been further endangered by repeated U.S.-Iraq conflicts which resulted in large oil spills into the gulf. The current population of Persian Gulf dugongs is around 7,500, but their status is currently not well known.^[22]

An endangered population of 50 or fewer dugongs survives around Okinawa.^[23]

Ecology and life history

Feeding

Bones in the forelimb can fuse variously with age

Dugongs are referred to as "sea cows" because their diet consists mainly of sea-grass. They are particular about their diets, with certain "fields" of sea-grass being regularly cropped. Unlike manatees, dugongs are exclusively benthic, or bottom feeders. Their primary feeding mechanism is uprooting sea-grass by digging furrows in the seafloor with their snouts. Reflecting this, the muscular snouts of dugongs are more dramatically tapered than those of manatees.

Dugongs in Moreton Bay, Australia, are omnivorous, feeding on invertebrates such as polychaetes when the supply of their choice grasses decreases.^[24] They will also go to any fresh water sources for drinking. Without these fresh water sources, many would not survive. The number of these fresh water sources is beginning to decline. The dugong population is predicted to enter a steep decline.^{[citation needed]}

Reproduction

Dugong mother and offspring from East Timor

Dugongs bear one calf at a time after an approximately 13-month gestation. The calf nurses for two years and reaches sexual maturity between the ages of 8-18, longer than in most other mammals. Despite the longevity of the Dugong, which may live for fifty years or more, females give birth only a few times during their life and invest considerable parental care in their young.^[25]

Importance to humans

Ancient interaction

Ipoh's Gua Tambun - Dugong Neolithic Wall Painting

There is a 5,000-year old wall painting of a dugong, apparently drawn by neolithic peoples, found in Tambun Cave of Ipoh city in the state of Perak, Malaysia. This was discovered by Lt.R.L Rawlings in 1959 while on a routine patrol.

In Umm al-Quwain (UAE), a marine sanctuary, build-up with more than 40 skeletons of dugongs was, found by a French archeology mission in 2009. 5140 BP (islet of Akab).

During the Renaissance and the Baroque eras, dugongs were often exhibited in wunderkammers. They were also presented as Fiji mermaids in sideshows.

Dugongs' or sea cows' hides were used as coverings in the building of the Old Testament's portable worship tent known as The Tabernacle as referenced in the Holy Bible's book of Exodus.

Dugong in captivity

Worldwide, only six dugongs are held in captivity. Two are the featured attraction of Toba Aquarium in Toba, Mie, Japan; another, named Gracie, is at Underwater World, Singapore; a fourth is in Sea World Indonesia ^[26] which was saved after being caught by a local fisherman; and the last two (Pig, a 10-year-old male, and Wuru, a four-year-old female) formerly lived at Sea World on the Gold Coast, Queensland, Australia, but in December, 2008, they were relocated to Sydney Aquarium.^[27]

Conservation

Dugong are hunted for food throughout their wildlife range, usually for their meat and blubber.^{[citation needed]} The seagrass beds which the dugong depend on for food are threatened by eutrophication caused by agricultural and industrial runoff, and dugong waste matter is a major food source for other aquatic creatures. Due to their shallow-water feeding habits, dugong are frequently injured or killed by collisions with motorized water vessels. Because of their large size, they have only a few predators. These include sharks, killer whales and saltwater crocodiles.

The U.S. and Japanese governments want to build a new military base on a coral reef close to Henoko, in Nago county, Okinawa. This plan has generated strong protests from Okinawans who are concerned that the local environment, home to the dugong, would be ruined.^{[citation needed]} Greenpeace stepped up its campaign protesting the Okinawa base expansion in the summer of 2007, as authorities recommenced their airbase development plans.^[28]

Around the waters of Papua New Guinea, natives have been known to hunt both dugongs and dugong predators, such as sharks.

See also

• Evolution of sirenians
• Dugong (Weebl's cartoon)
• Dewgong

References

External links

• Arkive (Dugong dugon)
• Roberto Sozzani The Dugong
• UNEP Dugong Action Plan
• Sirenian International
• Australian Museum Online Dugong Factsheet
• Dugong in Myanmar
• Ph2otos.com - Dugong in Egypt
• Dugong Conservation Project, India

From LoveToKnow 1911

DUGONG, one of the two existing generic representatives of the Sirenia, or herbivorous aquatic mammals. Dugongs are distinguished from their cousins the manatis by the presence in the upper jaw of the male of a pair of large tusks, which in the female are arrested in their growth, and remain concealed. There are never more than five molar teeth on each side of either jaw, or twenty in all, and these are flat on the grinding surface. The flippers are unprovided with nails, and the tail is broad, and differs from that of the manati in being crescent-shaped instead of rounded. The bones are hard and firm, and take a polish equal to that of ivory. Dugongs frequent the shallow waters of the tropical seas, extending from the east coast of Africa north of the mouth of the Zambezi, along the shores of the Indian, Malayan and Australian seas, where they may be seen basking on the surface of the water, or browsing on submarine pastures of seaweed, for which the thick obtuse lips and truncated snout pre-eminently fit them. They are gregarious, feeding in large numbers in localities where they are not often disturbed. The female produces a single young one at a birth, and is remarkable for the great affection it shows for its offspring, so that when the young dugong is caught there is no difficulty in capturing the mother. Three species - the Indian dugong (Halicore dugong), the Red Sea dugong (H. tabernaculi) and the Australian dugong (H. australis) - are commonly recognized. The first is abundant along the shores of the Indian Ocean, and is captured in large numbers by the Malays, who esteem its flesh a great delicacy; the lean portions, especially of young specimens, are regarded by Europeans as excellent eating. It is generally taken by spearing, the main object of the hunter being to raise the tail out of the water, when the animal becomes perfectly powerless. It seldom attains a length of more than 8 or 10 ft. The Australian dugong is a larger species, attaining sometimes a length of 15 ft.; it occurs along the Australian coast from The Dugong.

Moreton Bay to Cape York, and is highly valued by the natives, who hunt it with spears, and gorge themselves with its flesh, when they are fortunate enough to secure a carcase. Of late years the oil obtained from the blubber of this species has been largely used in Australia as a substitute for cod-liver oil. It does not contain iodine, but is said to possess all the therapeutic qualities of cod-liver oil without its nauseous taste. A fullgrown dugong yields from io to 12 gallons of oil, and this forms in cold weather a thick mass, and requires to be melted before a fire previous to being used. The flesh of the Australian dugong is easy of digestion, the muscular fibre when fresh resembling beef, and when salted having the flavour of bacon. In the earliest Australian dugong-fishery natives were employed to harpoon these animals, which soon, however, became too wary to allow themselves to be approached near enough for this purpose, and the harpoon was abandoned for the net. The latter is spread at night, and in its meshes dugongs are caught in considerable numbers. (R. L.*)

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Definition from Wiktionary, a free dictionary

Dugong

Translingual

Etymology

Proper noun

Wikipedia has an article on:

Dugong

Wikipedia

Dugong

1. a taxonomic genus, within family Dugongidae - the dugong

Wikispecies has information on:

Dugong

Wikispecies

Derived terms

• Dugong dugon the only species

Translations

• Korean: 듀공과
• Russian: дюгонь (d'ugón') m.

From Wikispecies

Dugong dugon

Taxonavigation

Main Page
Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Mammalia
Subclassis: Theria
Infraclassis: Placentalia
Superordo: Afrotheria
Cladus: Paenungulata
Ordo: Sirenia
Familia: Dugongidae
Subfamilia: Dugonginae
Genus: Dugong
Species: Dugong dugon

Name

Dugong Lacépède, 1799

Type species: Dugong indicus Lacépède, 1799

Synonyms

• Amblychilus Fischer von Waldheim, 1814
• Dugongidus Gray, 1821
• Dugungus Tiedemann, 1808
• Halicore Illiger, 1811
• Platystomus G. Fischer, 1803

References

• Dugong on Mammal Species of the World.
  Don E. Wilson & DeeAnn M. Reeder (editors). 2005. Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed).
• Tab. Div. Subd. Orders Genres Mammifères 14: 17.
• Mammal Species of the World, A Taxonomic and Geographic Reference, 3rd edition, 2005 ISBN 0801882214

Vernacular names

From BibleWiki

This word is found in Ex 25:5; Ex 26:14; Ex 35:7, Ex 35:23; Ex 36:19; Ex 39:34; Num 4:6, etc. The tabernacle was covered with badgers' skins; the shoes of women were also made of them (Ezek 16:10). Our translators seem to have been misled by the similarity in sound of the Hebrew tachash and the Latin taxus, "a badger." The revisers have correctly substituted "seal skins."

The Arabs of the Sinaitic peninsula apply the name tucash to the seals and dugongs which are common in the Red Sea, and the skins of which are largely used as leather and for sandals. Though the badger is common in Palestine, and might occur in the wilderness, its small hide would have been useless as a tent covering. The dugong, very plentiful in the shallow waters on the shores of the Red Sea, is a marine animal from 12 to 30 feet long, something between a whale and a seal, never leaving the water, but very easily caught. It grazes on seaweed, and is known by naturalists as Halicore tabernaculi.

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