Confused by a class within a class or an order within an order? Please see our brief essay. To cite this page: Myers, P. Espinosa, C. Parr, T. Jones, G. Hammond, and T. The Animal Diversity Web online. Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe.
Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control. Additional Information Encyclopedia of Life. Dugong dugon dugong Facebook. Kingdom Animalia animals. Animalia: information 1 Animalia: pictures Animalia: specimens Animalia: sounds Animalia: maps Eumetazoa metazoans.
Eumetazoa: pictures Eumetazoa: specimens Eumetazoa: sounds Eumetazoa: maps Bilateria bilaterally symmetrical animals. Mammals survive successfully in most habitats because they are endothermic and show a wide range of adaptations. Orders of mammals All classes are further sub-divided into Orders. We will investigate Class Mammalia further.
Order Monotremata: Egg laying mammals. Mammary glands lack nipples. There are only two monotremes in the world, both of which are only found in Australia - the platypus and the echidna.
Order Marsupialia: Pouched mammals. Young born undeveloped, then grow further on a nipple in the pouch, e. Order Primates: Internal development of young with placenta, eyes usually directed forward, nails instead of claws, e. Other separate orders group together: Rats, mice, porcupines - Rodentia Rabbits, hares - Lagomorpha Dolphins, whales - Cetacea Tigers, dogs, cats, foxes - Carnivora Seals, walruses - Pinnipedia Elephants - Proboscidea Dugongs, manatees - Sirenia Horses, rhinoceroses - Perissodactyla Herbivores such as sheep, pigs, camels, deer, giraffes - Artiodactyla.
These groups are distinguished by different characteristics. However, the distinctions are man-made, which means that differing opinions will result in minor variations in classification systems.
Not all biologists agree! Each order is then further divided into Families, Genera sing. Genus and Species sing. The binomial two names scientific name tells the Genus with a capital letter and the species always written in lower case.
Visual communication is limited due to poor eyesight, and is mainly used for activities such as lekking for courtship purposes. Mothers and calves are in almost constant physical contact, and calves have been known to reach out and touch their mothers with their flippers for reassurance. Dugongs are semi-nomadic , often traveling long distances in search of food, but staying within a certain range their entire life. It is thought that these movements are caused by changes in seagrass availability.
Their memory allows them to return to specific points after long travels. Daily movement is affected by the tides. In areas where there is a large tidal range, dugongs travel with the tide in order to access shallower feeding areas.
In Moreton Bay, dugongs often travel between foraging grounds inside the bay and warmer oceanic waters. At higher latitudes dugongs make seasonal travels to reach warmer water during the winter. Occasionally individual dugongs make long-distance travels over many days, and can travel over deep ocean waters. Dugongs, along with other sirenians , are referred to as "sea cows" because their diet consists mainly of seagrass.
When eating they ingest the whole plant, including the roots, [17] although when this is impossible they will feed on just the leaves. In other southern areas of both western and eastern Australia, there is evidence that dugongs actively seek out large invertebrates. This does not apply to dugongs in tropical areas, in which fecal evidence indicates that invertebrates are not eaten. Most dugongs do not feed on lush areas, but where the seagrass is more sparse.
Additional factors such as protein concentration and regenerative ability also affect the value of a seagrass bed. Seagrasses of a lower seral are preferred, where the area has not fully vegetated.
Only certain seagrass meadows are suitable for dugong consumption, due to the dugong's highly specialized diet. There is evidence that dugongs actively alter seagrass species compositions at local levels. Dugongs may search out deeper seagrass. Feeding trails have been observed as deep as 33 metres ft , and dugongs have been seen feeding as deep as 37 metres ft. Dugong feeding may favor the subsequent growth low-fibre, high-nitrogen seagrasses such as Halophilia and Halodule. Due to their poor eyesight, dugongs often use smell to locate edible plants.
They also have a strong tactile sense , and feel their surroundings with their long sensitive bristles. They have been known to collect a pile of plants in one area before eating them.
This leaves furrows in the sand in their path. A dugong reaches sexual maturity between the ages of eight and eighteen, older than in most other mammals. Mating behaviour varies between populations located in different areas. This greatly increases the chances of conception.
Females give birth after a to month gestation , usually to just one calf. Dugongs have historically provided easy targets for hunters, who killed them for their meat, oil, skin, and bones. As the anthropologist A. In some areas it remains an animal of great significance, [18] and a growing ecotourism industry around dugongs has had an economic benefit in some countries. There is a 5,year-old wall painting of a dugong, apparently drawn by neolithic peoples, in Tambun Cave , Ipoh , Malaysia.
This was discovered by Lieutenant R. L Rawlings in while on a routine patrol. Dugongs feature in Southeast Asian, especially Austronesian , folklore. Because of this, it is considered bad luck if a dugong is killed or accidentally dies in nets or fish corrals in the Philippines, some parts of Sabah Malaysia , and northern Sulawesi and the Lesser Sunda Islands Indonesia. Dugongs are predominantly not traditionally hunted for food in these regions and they remained plentiful until around the s.
Conversely, dugong "tears" are considered aphrodisiacs in other parts of Indonesia , Singapore , Malaysia , Brunei , Thailand , Vietnam , and Cambodia.
They are actively hunted in these regions, in some places to near-extinction. In Palau , dugongs were traditionally hunted with heavy spears from canoes. Although it is illegal and there is widespread disapproval at killing dugongs, poaching remains a major problem.
Dugongs are also widely hunted in Papua New Guinea , the Solomon Islands , Vanuatu , and New Caledonia ; where their meat and ornaments made from bones and tusks are highly prized in feasts and traditional rituals.
However, hunting dugongs is considered taboo in some areas of Vanuatu. Some aborigines regard dugongs as part of their Aboriginality. Local fishermen in Southern China traditionally revered dugongs and regarded them as "miraculous fish". They believed it was bad luck to catch them and they were plentiful in the region prior to the s.
Beginning in the s, a wave of immigrants from other regions that do not hold these beliefs resulted in dugongs being hunted for food and traditional Chinese medicine. This led to a steep decline in dugong populations in the Gulf of Tonkin and the sea around Hainan Island. Carved ribs of dugongs in the shape of butterflies a psychopomp are found throughout Okinawa. They were commonly hunted throughout Japan up until around the s.
Dugongs have also played a role in legends in Kenya, and the animal is known there as the "Queen of the Sea". Body parts are used as food, medicine, and decorations. In the Gulf states, dugongs served not only as a source of food, but their tusks were used as sword handles. Dugong oil is important as a preservative and conditioner for wooden boats to people around the Gulf of Kutch in India, who also believe the meat to be an aphrodisiac.
During the Renaissance and the Baroque eras, dugongs were often exhibited in wunderkammers. They were also presented as Fiji mermaids in sideshows. Dugong numbers have decreased in recent times. For a population to remain stable, 95 percent of adults must survive the span of one year.
The fact that they live in shallow waters puts them under great pressure from human activity. Research on dugongs and the effects of human activity on them has been limited, mostly taking place in Australia. In many countries, dugong numbers have never been surveyed. As such, trends are uncertain, with more data needed for comprehensive management. The last major worldwide study, made in , concluded that the dugong was declining and possibly extinct in a third of its range, with unknown status in another half.
Kenya has passed legislation banning the hunting of dugongs and restricting trawling, but the dugong is not yet listed under Kenya's Wildlife Act for endangered species. Mozambique has had legislation to protect dugongs since , but this has not been effectively enforced.
The United Arab Emirates has banned all hunting of dugongs within its waters, as has Bahrain. The UAE has additionally banned drift net fishing. India and Sri Lanka ban the hunting and selling of dugongs and their products.
Japan has listed dugongs as endangered and has banned intentional kills and harassment. Hunting, catching, and harassment are banned by the People's Republic of China. The first marine mammal to be protected in the Philippines was the dugong, although monitoring this is difficult. Palau has legislated to protect dugongs, although this is not well enforced and poaching persists. Indonesia lists dugongs as a protected species; [12] however, protection is not always enforced and souvenir products made from dugong parts can be openly found in markets in Bali.
Vanuatu and New Caledonia ban hunting of dugongs. Dugongs are protected throughout Australia, although the rules vary by state; in some areas, indigenous hunting is allowed. Most currently live in established marine parks , where boats must travel at a restricted speed and mesh net fishing is restricted.
Despite being legally protected in many countries, the main causes of population decline remain anthropogenic and include hunting, habitat degradation , and fishing-related fatalities. Most issues with industrial fishing occur in deeper waters where dugong populations are low, with local fishing being the main risk in shallower waters. In areas such as northern Australia, hunting remains the greatest impact on the dugong population. Vessel strikes have proved a problem for manatees, but the relevance of this to dugongs is unknown.
Ecotourism has increased in some countries, although the effects remain undocumented. It has been seen to cause issues in areas such as Hainan due to environmental degradation. The effects are unknown. While international cooperation to form a conservative unit has been undertaken, [] socio-political needs are an impediment to dugong conservation in many developing countries. The shallow waters are often used as a source of food and income, problems exacerbated by aid used to improve fishing.
In many countries, the legislation does not exist to protect dugongs, and if it does it is not enforced. Oil spills are a danger to dugongs in some areas, as is land reclamation.
In Okinawa the small dugong population is threatened by United States military activity. Plans exist to build a military base close to the Henoko reef, and military activity also adds the threats of noise pollution, chemical pollution, soil erosion, and exposure to depleted uranium.
If dugongs do not get enough to eat they may calve later and produce fewer young. Sewage , detergents , heavy metal , hypersaline water, herbicides , and other waste products all negatively affect seagrass meadows. Human activity such as mining, trawling , dredging , land reclamation , and boat propeller scarring also cause an increase in sedimentation which smothers seagrass and prevents light from reaching it.
This is the most significant negative factor affecting seagrass. Halophila ovalis —one of the dugong's preferred species of seagrass—declines rapidly due to lack of light, dying completely after 30 days. Extreme weather such as cyclones and floods can destroy hundreds of square kilometres of seagrass meadows, as well as washing dugongs ashore. The recovery of seagrass meadows and the spread of seagrass into new areas, or areas where it has been destroyed, can take over a decade.
Most measures for protection involve restricting activities such as trawling in areas containing seagrass meadows, with little to no action on pollutants originating from land. In some areas, water salinity is increased due to wastewater , and it is unknown how much salinity seagrass can withstand.
Dugong habitat in the Oura Bay area of Henoko, Okinawa, Japan , is currently under threat from land reclamation conducted by Japanese Government in order to build a US Marine base in the area. The Australian state of Queensland has sixteen dugong protection parks, and some preservation zones have been established where even Aboriginal Peoples are not allowed to hunt.
Worldwide, only three dugongs are held in captivity. Gracie, a captive dugong at Underwater World, Singapore , was reported to have died in at the age of 19, from complications arising from an acute digestive disorder. Remember Me.
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Marine mammal, sole living member of the family Dugongidae. Not to be confused with Dougong. Temporal range: Miocene-recent [1]. Conservation status.
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