The Dugong Of The Isle Of Pines, New Caledonia, French Territory (Dugong Dugon)
This month’s article series will discuss the Isle Of Pines, belonging to the French territory known as New Caledonia. New Caledonia, is in the South Pacific just north of Brisbane, Australia. It is south of the country of Vanuatu, with its capital being “Noumea”. The Isle of Pines is south of mainland New Caledonia, & it has an approximate population of 2,000. It is approximately 26.91 nautical miles (30.967475 miles or 49.83732 kilometers) from mainland New Caledonia, 793.87 nautical miles (913.56928 miles or 1470.24724 kilometers) from Australia, & 3,784.67 nautical miles (4355.3204536 miles or 7009.20884 kilometers) from the mainland country of Malaysia. The island is famed for its beautiful coral reefs as it is surrounded by the New Caledonian Barrier Reef. It is also known for its beautiful forests of pine trees which contrast with the sea to make a beautiful landscape, which is the reason for its name. It is located in the commune of L'Île-des-Pins, which encompasses many islands, with The Isle of Pines being the largest. This Island has many interesting land, & marine flora, mainly due to its proximity to the New Caledonian Barrier Reef. Not only that, but the island has lush mangroves that directly connect lagoons & forests. The New Caledonian Barrier Reef attracts many strange & interesting species from around the globe, one of which is the Dugong. The Dugong is a strange species of large marine sirenian that looks vaguely like a manatee, however they are much different. Though they are distantly related to manatees, they are far closer to Stellers Sea cow. They are currently believed to be the direct descendants of the Stellers Sea cow. It is the only living member of its family, as all other species of its family were killed off. Dugongs are extremely large creatures that are enormous, yet they only eat marine plants. Though they may look frightening, they are perfectly harmless & the worst that they can do to somebody is damage their boat by going too close to the propeller. They are extremely curious creatures, & will most likely look you over if you get near them. They are extremely lazy, so you can most likely find a few of them napping in the afternoon in the lagoons. The Isle Of Pines is the place with the third largest population of dugongs in the world, which is why they can be seen so often around the Isle. In this article, we will discuss the Discovery of the Life Of the Dugong, The Mating Tactics, Procedures, Cycles, & Practices of the Dugong, The Distribution Of The Dugong, & Finally The Scientific Detailings Of The Dugong. With that being said, let us delve into this gentle beast of a creature.
The Discovery & The Life Of The Dugong
The dugong was first described in 1765 in a novel called “Histoire Naturelle”, however, it was officially classified in taxonomic terms by Otto Friedrich Müller, a Danish naturalist, taxonomist, & scientific illustrator. It is unknown how he first heard of it, however it can only be assumed it was by returning sailors. It was officially classified in 1776 under the name Trichechus Dugon. Both Sexes in Dugongs will usually grow a maximum length of 13 feet long. Dugongs also weigh a maximum weight of 595 pounds, which does not differ between sexes usually. Females tend to outweigh males by a small margin, & measure longer than males by a small margin, which means they do display a small amount of sexual dimorphism. They have a life span of 70 years usually, & this does not differ between sexes. The oldest living Dugong was approximately 73 years, old & was female. Dugongs are Sirenians, meaning that they are sea cows. Sea cows, of all the ungulates, are hypothesized to be the least intelligent. Of all mammals, the manatees & dugongs have the lowest brain-to-body mass ratio. Since there are very few other ways to measure intellect, they are most likely the most simple-minded of all ungulates. Although dugong's diets are extremely poor as they are vegetarians, so there may be a correlation between their diet & their brain size. Sirenians have existed since the Eocene or 50 million years ago, from 4-legged ungulates, similar to Pakicetus. They did not diversify into the species we now know until the Oligocene epoch,& Miocene epoch. The dugongs are great communicators despite their small brains. They will often communicate through clicks, barks, & various vocal sounds. Their clicks can be between 3 & 18 hertz, & up to 60 milliseconds long. They are very social creatures, & spend the majority of their lives in pairs, or alone. They do occasionally join herds, however they may go their entire lives with a herd. A herd can be up to 200 dugongs, all in one area. These herds are sometimes unstable though, & are prone to collapsing off into subgroups. It is uncommon to see herds as seagrass beds are not able to support a large group of dugongs for extended periods, due to there simply not being enough & there needing time for more seaweed to grow.
They are not territorial creatures in terms of land, but the males are territorial over females during mating season. They are actively being observed by scientists. They also have been captured as a species before, & there are a total of only 3 dugongs kept in aquariums worldwide. Additionally, they are not aggressive towards humans at all, but occasionally they may accidentally bump into humans, & due to their massive size, they may bruise the person on accident or capsize their vessel. They truthfully are not aggressive creatures, & are gentle behemoths. They are semi-migratory creatures & will migrate approximately 150 to 500 miles in search of food, but will generally stay in the same area their entire lives. The dugong swims by throwing its tail in an up & down motion to propel, & steering with their flippers. They are also able to propel with their flippers, though they don’t do that very often. Their average speed is approximately 6.21371 miles per hour (9.999996906 kilometers per hour). Dugongs don’t sleep in the general way we think of it, they simply close their eyes halfway, & they sleep on the bottom of the sea to avoid predators. Because they do breathe air because they are mammals, they are only able to slip in short bursts before getting breaths. They are occasionally the victim of shark attacks, & killer whale attacks, because they are large & make good eating, but their size also puts them at an advantage. Due to how massive they are, sharks are often not able to consume them properly due to the constraints of the jaw. They are unfortunately extremely susceptible to boat accidents, as they will approach vessels out of curiosity & which will cause them to be struck by the hull or the propeller of the vessel. They eat only consume oceanic vegetation, & cannot consume meat. They are not cannibalistic in any way, shape, or form. They are not strictly nocturnal hunters, & they will consume food both day & night. They consume on average 30.00000968 kilograms (66.1387 pounds) of seaweed in one day. Dividing the average weight by the average amount of food they eat per day, they need approximately 0.111157479 pounds of seaweed, per pound of dugong. They locate food by using the bristles on their snout to help find it. Their metabolism is extremely slow because they move slowly, & are rather sedentary creatures. The Dugong is a large animal, greyish brown, with a flattened fluked tail, like that of a dolphin. Their skin may change depending on the age of the They are distinct in that they have no dorsal fin, & paddle-like flippers with distinctive down-turned snout. Compared to a manatee, it is obvious that it is a dugong due to their snouts being so flat, & due to their lips hanging off the side of their snout, similar to a bloodhound. They also have a distinct shape, unlike manatees, which are very blob-like. They also have small tusks which protrude from their snout occasionally. The IUCN Red List states that they are vulnerable to extinction, which makes them classified as vulnerable.
The Mating Tactics, Procedures, Cycles, & Practices Of The Dugong
Dugongs breed via sexual reproduction, & cannot breed via asexual reproduction. They are not monogamous creatures & mate with various creatures throughout their lives. Their official mating system is classified as polyandrous. They are also not hermaphroditic in any way, & cannot change sexes, though genetic anomalies can occur in which a dugong is intersex. Dugongs sexually mature at 6 years for females, & up to 12 years for males. The gestation period for a dugong is approximately 12 months or one calendar year. However, it can be up to 14 months, depending on the dugong. It is unknown what age a dugong is most fertile at for either sex. This species has no specific breeding month, & mating is a year-round event. This species does lactate, & the females will nurse the calves while they are young. They will give birth every 2.5 to 7 years, & they have no upper limit on what age they can give birth. However, after the sixth calf, a female usually stops having babies. They only give birth to one calf at a time due to how large a calf is, & virtually never have twins. The exact mating ritual in dugongs does differ depending on the exact location, so for this article, we will be discussing specifically the mating ritual most common in Australia & Oceania. To breed, they will all gather in a massive group called a lek, where the males will compete for mates. The males will compete in sparring, & various other aggressive activities to attract the females. The males will do their best to defend this lek territory & be the toughest dugong. After this, the first stage of the actual ritual will occur, this is known as the following stage. This is a stage in which a group of 5 to 10 males will follow a singular female around. After this comes the fighting stage, in which the males will all fight each other, lunge at one another, & thrash their tails at one another. After this phase, the mounting stage will occur. This stage is the stage in which copulation occurs. What will happen is that a male will mount the female from below, & the other males will all try to reach that position. Several males will mount the female during this time. Once the mating ritual is completed, the father will swim off, never to be seen again. The testicles of the male are not located externally, so this complicates breeding slightly. After the gestational period is over, the mother will live-birth one calf. At birth, calves average 66.1387 pounds (30.00000968 kilograms), & 3.93701 feet (1.200000648 meters) long. Additionally, the skin of the calf will be a pale cream color. Calves will nurse from their mothers until 18 months, at which time they will begin consuming solid foods. They will continue to nurse from their mother until after they begin consuming solid foods. Calves can often be seen riding on their mother's backs, as mothers cannot have their children stray far. The calves will mature at 5 to 12 years, after which the calves will go off to have children of their own.
The Distribution Of The Dugong
Dugongs are found in the coastal & warm waters of the Indian Ocean, & the Western Pacific. They are found on the coast of Australia, throughout Oceania, & on the west coast of Africa, as well as the northern coast of Madagascar. They are also found on the western coast of India, but surprisingly not on the eastern coast of India. Strangely enough, it is also found in the Persian Gulf. These populations of Dugongs usually stay in the same areas their entire lives, which makes it so that different populations have different practices in things like mating. Usually, these practices don’t get spread across the different dugong populations, & stay in their enclosed location. There are no dugongs in the Atlantic or anywhere up near Hawaii. They stay in coastal waters usually as these have the most seagrass for them to consume. Usually, they can be found at a depth of 33 feet (10.0584 meters), though they can travel as deep as 121 feet (36.8808 meters) while in search of deep-sea seagrasses, such as Halophila spinulosa (Fern Grass). Currently, dugongs are found in approximately 37 countries & territories. At this time they have no subspecies.
The Scientific Detailings Of The Dugong
By far the most interesting thing about the Dugong would have to be their uniquely shaped snout. Their snout is downturned at a sharp angle, making them look rather intimidating. The reason for this interesting shape is that this shape helps them uproot seagrass more easily. Dugongs are herbivores, which makes their teeth shape extremely strange. Their teeth are thick & dull, with a large split down the center of their tooth, with two large dents pointed inwards on the tooth. Dugongs have on average 36 teeth with 2 rows of teeth used for grinding up marine vegetation. These teeth are made of bone & are extremely tough. Plaque will form on them as well as they do on human teeth. They usually have their tusks pierced out of their face later in life, near the time they sexually mature. Only males will ever see their tusks, while females will be tusk-less. This species is a vertebrate, & has approximately 57 to 60 vertebrae. A dugong has an extremely wide ribcage as well as a straight spine into the tail. It also has finger bones that have been hidden underneath its thick skin. The specific population of dugongs near Australia & New Caledonia that we are discussing, has a big issue with parasites & disease. During the lifetime of a dugong, there are many different kinds & ways for a dugong to get an infection or a parasite. Once the dugong has a parasite, they are incredibly hard to get rid of. The most common kind of parasites in dugongs are helminths (Parasitic worms). Now these parasitic worms usually are looking to live in the gastrointestinal system of the Dugong, making it even harder for them to be gotten rid of because they can’t be flushed out. For this reason, approximately 30 percent of all the deaths since 1996 in the Australian & New Caledonian population of dugongs have been due to a parasite or infection from parasites. Unfortunately, we have no exact way of determining this, so 30 percent is not entirely exact. Their phylum is Chordata meaning that they developed these 5 characteristics all species under the phylum of Chordata develop 5 similar characteristics either In adulthood or as juveniles. The characteristics that they develop include, a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal Slits, & a post-anal tail. Their class is Mammalia. Mammalia is classified by the production of milk by the mother for their child to nurse, a neocortex which is a region of the brain, some capacity for fur or hair, & three middle ear bones. There are currently 6,400 species categorized under the class of Mammalia. Mammalians also tend to be self-aware & able to use tools, no matter the species. Their order is Sirenia. This is an order that holds the majority of all manatees & dugongs as they are closely related. A defining characteristic of this order is the fact that they are all fully herbivorous & they all grow to be incredibly large. Their family is Trichechidae. All surviving species in this family are classified as manatee. There are several extinct genera classified under this family however they do not count for this. There are currently 8 species under this family. Their Family is Dugongidae, which has only 1 surviving species, the dugong. This family has many fossils under it as well, with several extinct genera. Their genus is Dugong, which they are the only species in. Their Binomial name is Dugong Dugon.
Directories / Credits
“Dugong Dugon” was Written by Unknown, & Published on an Unknown Date. Published By the Society for Mammal Mammalogy. Retrieval Date: June 19th 2023.
“Facts About Dugongs” Written by Unknown, Published at an Unknown Date. Published by World Wildlife. Retrieval Date: June 19th 2023.
“Dugong” Written by Unknown, Published at an Unknown Date. Published by Thai National Parks. Retrieval Date: June 19th 2023.
“Morphology & Organ Weight Of Dugongs (Dugong Dugon) In Thai Waters” Written by Kajana Adulyanukosol, Phaothep Cherdsukjai, & Pantaruk Boukaew, January 2011. Published by Research Gate. Retrieval Date: June 19th 2023.
“Natural History Of the Dugong Dugon”, Written by Unknown & Published at an Unknown Date. Published by the Center for Biological Diversity. Retrieval Date June 19th, 2023.
“Dugong”, Written By Unknown & Published at an Unknown Date. Published By The Great Barrier Reef Foundation. Retrieval Date: June 19th 2023.
“Observations of the mating behavior in the dugong (Dugong Dugon)” Written by Anthony Preen, August 2006. Published By Research Gate. Retrieval Date: June 19th 2023.
“Dugong Dugon: dugong” Written By Nicole Macdonald, Unknown Date. Published by the Animal Diversity Web. Retrieval Date: June 19th, 2023
Strategic Partnerships
Reel Guppy Outdoors
SharkedSkooler
Marine Enthusiasts Podcast
StemScribe
Our Loyal Patrons
Ms. Paloma Rodriguez Ochoa
Comments