The Myths and Facts Emily Comstock




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Dugongs Comstock

Dugongs

The Myths and Facts

Emily Comstock

English 11/Spackman

Abstract

This research paper contains five online resources from the Pioneer search engine. The resources are based from online articles and books. This paper also contains information from a hard cover text book titled Guide to Marine Mammals of the World. In this research paper you will discover where the legend of mermaids first started, what dangers threaten the gentle dugong, how dugongs differ from manatees, and you will read about their life in the sea. Dugongs belong in the order sirenians and are called many names including Sea Cow and Sea Pig. Dugongs are more social than manatees; they are commonly seen traveling in small groups. The dugong’s whale-like tail gives sailors the impression of a mermaid; this is where the legendary fish woman starts to come alive. These vegetarians are slow in movement and breeding; this is a problem in escaping from boat propellers and in keeping their species alive in the world. The sad thing is if we don’t act fast, they may not be around in the next 20 years.



Emily Comstock

Period 3/English 11

Topic: Dugong



For years sailors would talk about a mythical creature from the sea that would seduce men to the waters, they would call them mermaids but I call them dugongs. You probably have no idea what a dugong is and maybe even some of you thought I was talking about the pokemon. Well this report can clear that up for you and any questions you may have with it. The dugong is a gentle soul and it is also one of the marine mammals that are the closest to extinction.

Classification: Kingdom: Animalia, Phylum: Chordata, Class: Mammalia, Order: Sirenia, Family: Dugongidae, Genus: Dugong, Species: Dugong, dugong. (Attenborough, 2003-2011)

Names: Other names they receive include: Sea cow, sea pigs, sea camels, and sirens. The name, “dugong”, itself means lady of the sea or mermaid. Its scientific name is Dugong dugong; easy to remember huh? (Reeves R., 2002)

Description: For those that don’t know, a dugong is similar in looks to a manatee, however, its tail is V shaped like a dolphin’s. Its skin is smooth and ranges in color from brownish to dark gray. The nostrils are at the very tip of the nose. It has a flappy upper lip where evolutionary a trunk used to be but has since shrank. They have short hairs along their body but mostly visible at their muzzle. Adult males have short tusks. Some females can have them as well but they are not usually visable. It is the smallest member of the sirens wieghing up to 800 pounds and 10 feet in length. The dugong also communicates using odd little chirping sounds. (Attenborough, 2003-2011) (Reeves R., 2002)

Characteristics: The dugong has poor eye sight and acute hearing but seem to have a good sense of smell. Their large flappy upper lip is perfect for eating by pulling sea grass to the mouth As it grazes on the sandy floor, sand drifts around and when it feeds this makes it look like a vacuum. The tusks also aid in eating.

Range: Dugongs range is just about anywhere. Perferably warmer waters but have been found on rare occassions in colder waters. Basicly, human activity reflects the population of a given area. They are most abundent in western Pacific and Indian Oceans specifically along the coasts of Australia, Asia, and some in Africa. Dugongs can dive to depths of 73 feet deep; but perfer to swim in shallower areas because of food, predators and because they can only hold their breath for 8 mintes. (Reeves R., 2002)

Age: Dugongs can live to a maximum of 73 years in captivity; however we only seem to find dugongs that are just over 50 years old in the wild. Fossil records show they have been around for at least 50 million years and were first discovered in 1776. (Reeves R., 2002)

Myths: Female dugongs have been mistaken by sailors as mermaids. The dugong’s whale-like tail makes the sailors think it is the tail of a mermaid and mistakes the female dugong’s tits on its flippers as breasts. It is actually a theory that when Columbus sailed the ocean he might have seen a manatee instead of a mermaid. The dugongs have inspired brilliant paintings and stories of mermaids. The dugong even changed culture practices and beliefs for some sailors and natives. They would pray to the mermaid to bring good catches and protection. However some beliefs became harmful to dugongs, like the belief that the oils from a dugong were perfect for healing. (Vaughan, 2001)

Relatives: Manatees are cousins of the dugong and both are close relatives to the elephant (based on the anatomy). Though dugongs have been thought to be a finless porpoise or dolphin that the fact they have no dorsal fin and their nostrils are at the tip of their snout rules them out as being a whale or dolphin. There was a species of dugong discovered in the 1700’s, called the Steller Sea Cow. This only other member of the Dugongidae was hunted to extinction in just 27 years after its discovery. (Reeves R., 2002)

Steller Sea Cow (Hydrodamalis gigas): This large mammal was the closest relative of the dugong. It was first discovered in 1741 by Georg Wilhem Steller and just 27 years after the discovery it was hunted to extinction by sealers and Sea Otter hunters. This large mammal grew to 30 feet long and weighed between 8 and 10 tons. The Steller’s Sea Cow had rough skin, lacked teeth and finger bones. They had a small head, short neck, stubby flippers and a medium sized whale tail. They fed on a variety of kelp and other algae. When it swam the seas it ranged only around Bering Sea and Copper islands. (Reeves R., 2002)

Dugongs Vs Manatees: Many people mistake a manatee with a dugong but one of the biggest differences between them is that dugongs have tusks and don’t have teeth replacement, while manatees do not have tusks and do have teeth replacement. The easiest way to tell them apart is a dugong has a whale-like tail and the manatee has a tail that looks similar to ping pong paddle. This is an easy way to tell them apart. Dugongs also tend to be more social than manatees because sightings prove that dugongs travel in small groups or in a large group of hundreds. Dugongs also differ from manatees by their chosen marine habitats. (Reeves R., 2002) (Taylor, 2001)

Food: Dugongs and manatees are the only marine mammals that are strictly vegetarian. It is important that we protect our ocean’s sea grass, because it’s the only food scource for dugongs and manatees. Dugongs only eat eel grass, which is the only flowering marine plant. (Brewer, 2003)

Predators: Their predators include sharks, killer whales, crocodiles and humans. (Reeves R., 2002)

Speed: The dugong’s average speed is 6 mph. (Reeves R., 2002)

Mating: When a female is in estrus she attracts a group of males. The males circle around her amd she tries to evade them. Next the males start splashing, tail thrashing, and pushing other males away in order to get into the mounting position. (Reeves R., 2002)

Females and Calf: The gestation lasts about 12 to 14 months and the calf can stay with its mother from 2 ½ to 7 years. Breeding occurs year round. Females can sometimes be seen with two calves but they usually only have the chance to breed once. They are slow breeders and that is another reason they have trouble staying off the path to extinction. (Reeves R., 2002)

Threats: The dugong is wanted on the black market and in other countries for its meat, oil, and hide. The biggest cause of their endangerment is their loss of habitat and sea grass. Their habitat is also being destroyed by pollution, making them move to other waters where there is more food but more danger. What is even more common is they get caught in fishing nets and since dugongs can only hold their breath for 8 minutes and plus the fact that they are under stress in the nets they can easily drown. Dugongs and manatees are slow swimmers and like to stay in shallow waters so when boats come by they don’t react fast enough and can just end up with cuts on their backs or worse, this is why 90% of dugongs have cuts on their backs from boat propellers. There have been cases where sailors would have a dugong caught in their nets and just leave them there because they fear if they report it they will get in trouble for illegal fishing in the area. Other countries also believe their meat and oils can be used for medicine and scientists and environmentalists try their best in explaining to the natives that if they continue hunting the dugongs it will lead to extinction. Young natives in Madagascar don’t even know the word for dugong in their language anymore. (Boulware) (Reeves R., 2002) (Vaughan, 2001)

Number: The most under threatened species in east Africa is the dugong. A record count in 1994 said dugong populations dropped 50-80% in just 8 years. In 1997, at least 23 dugongs washed up dead from the cause of fishing nets within a 2 month period and in 1998, 11 dugongs died in just 1 month. Right now there are about over 12,000 in just the Australian coast where they should be the most abundent. In the last 20 years, the population of these mammals in Indonesia went from 10,000 to 1,000. Currently there are 6 dugongs in captivity and the sad news is dugongs do not do well in captivity and there has never been a succsessful birth in captivity. (Reeves R., 2002) (Tager, 1999) (Boulware)

Ecosystem: When the dugong’s population declines the sea grass increases. This affects all marine animals from those that eat sea grass to those that use it as shelter. The loss of dugongs also affects tiger sharks a lot more; they are easier to catch than dolphins. If that doesn’t interest you, we, humans, rely on the dugong for income as tourist attractions. So if we fail to protect the dugong then it will backfire in our economy. (Reeves R., 2002)

Works Cited


Attenborough, D. (2003-2011). Arkive Home. Retrieved from Arkive: www.arkive.org

Boulware, J. (n.d.). The Vanishing Mermaid. AmericanWay .

Brewer, D. (2003). Manatees and Dugongs.

Reeves R., R. (2002). Guide to Marine Mammals of the World.

Tager, J. (1999). Going, going, dugong. Earth Island Journal .

Taylor, G. (2001). The Dugong Enigma. Nature Australia .



Vaughan, S. (2001). So long, dugong? Geographical .

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