Dugongs: ‘sirens’ of the sea
Photo by Gary Bell
Sightings of dugongs by early seafarers possibly gave rise to the mythology of mermaids and sirens. Given that a dugong has a wrinkly face and bristly nose, those sailors must have been at sea for a very long time!
But, while dugongs may not be as lovely as the imaginary beautiful creatures their sightings inspired, they nevertheless possess a wondrous beauty in their own right.
These mammals have incredibly expressive faces, and, unlike dolphins, eat only vegetation, using their strong lips to pull leaves from green marine plants. They can grow to a length of 2.2 to 3.4 m (7 to 11 ft), and usually weigh from 230 to 360 kg (500 to 800 pounds).
Dugongs are often referred to as sea cows because they ‘graze’ on the green algae and sea grass that forms ‘meadows’ in sheltered coastal waters. As they feed, dugongs uproot whole plants, leaving a tell-tale feeding trail.1 They live in generally shallow waters from the Red Sea and eastern Africa to the Philippines, New Guinea and northern Australia (including the Great Barrier Reef).
Dugongs are truly gentle creatures. This has made it very easy to exploit them and they have been heavily hunted for their meat, hide and oil—to the point where dugongs now need the protection of the law to prevent the species disappearing (like its close relative, the larger Steller’s sea cow, which hungry seal hunters wiped out within a few decades of its discovery in the Bering Sea in 1741).
In fact, in north-eastern Australia—where dugongs still live in reasonable numbers—indigenous elders recently called for tighter controls on native hunting rights of dugongs (and turtles) to prevent this protected species from being hunted to extinction.2
Aside from hunting, dugongs are threatened by oil spills, entanglement in fishing gear, shark and turtle nets, dynamite fishing, disruption to feeding by boats, and pollution caused by coastal development.5
Dugongs, Steller’s sea cows and freshwater manatees are members of the order Sirenia.6 They are the only large aquatic grass-eaters other than turtles.
Dugongs and freshwater manatees differ mainly in their snouts and tails: dugongs have a down-turned snout and forked tail, while manatees have a straight snout and rounded tail. Both have thick, tough skin, eyes without eyelids, small external ear openings and the trademark strong muscular upper lip.
Male dugongs can be distinguished by their ‘tusks’. These are two incisor teeth that break through in adulthood. Males and females have six cusped (with bumps or points) molars in each jaw, which fall out progressively until only two remain. These teeth, together with the horny pads at the front of each jaw, crush their grassy food.
Dugongs do not see well, but are believed to have acute hearing7 and a strong sense of smell. They also possess coarse, sensitive bristles that cover the upper lip of their large, fleshy snout. These help locate sea grass.5 They possibly live up to 70 years, and communicate underwater with squeaks and squeals.5
They are social creatures, tending to live in pairs or groups. Early last century, an enormous herd, estimated at covering 13 square kilometres (5 square miles), was sighted off the coast of Brisbane, Australia.8
Like dolphins, dugongs breathe by frequently visiting the surface, but these mammals breathe through the tip of the snout, which is protruded with the nostrils open. Dugongs can stay submerged for up to 10 minutes,6 but can’t hold their breath as long as dolphins, whales or porpoises.5They prefer to remain underwater, but do occasionally lift their heads entirely out of the water.
Relatively little is known about dugongs, particularly in relation to lifespan, age at maturity, rate of growth or even number of young produced in a lifetime. They are believed to carry their young for more than 150 days, giving birth usually to a single calf, which receives plenty of maternal care.8
Despite the fact they are marine mammals and have some resemblance to dolphins and whales, dugongs are classified separately from their fellow marine mammals. Incredibly, dugongs are grouped in the same suborder as elephants (Subungulata), largely because they have some similarities in their teeth and in the position of their mammary glands (between the front flippers/legs).9
Of course humans have mammary glands in a similar position—but evolutionists do not propose a common ancestor with dugongs to explain that similarity!
Furthermore, humans have a similar heart artery arrangement (‘aortic arch’) to dugongs, which is different from elephants.10 This shows that the argument from similarity for evolution (common ancestors) is a very selective one—applied where it seems to work, otherwise ignored. Large-scale similarities are due to a common Creator, not common ancestry.
In classifying dugongs with elephants, evolutionists assume that elephants evolved from water creatures. In other words the evolutionary path would be:
sea creature → land mammal → back to the sea (supposed ancestor of elephants and dugongs) → back to the land (elephants).11
But there is no fossil evidence that dugongs and manatees are related to any creature that now—or ever—walked on land.
Furthermore, the dugong’s body and breathing method are ideal for a marine mammal, and their teeth, horny pads for crushing food, tough upper lip and bristly snout are perfectly designed for their underwater vegetarian diet. It is therefore most likely that dugongs, Steller’s sea cows and manatees all descended from a dugong-manatee kind created by God on Day 5 of Creation Week (Genesis 1:20–23).
References and notes
- Great Barrier Reef Marine Park Authority: Facts about dugongs, www.gbrmpa.gov.au/corp_site/info_services/publications/dugong, 2 September 2003. Return to text.
- Elders to end dugong plunder, The Sunday Mail (Queensland), 17 August 2003, p. 44. Return to text.
- Exodus 25:5. Return to text.
- Exodus 26:14 (in the Holman Christian Standard Bible, and the New International Version 1984—other sea cow references include Exodus 35:7, 35:23 and 36:19). Return to text.
- The Humane Society of the United States, www.hsus.org/ace/18871, 6 August 2003. Return to text.
- Encyclopaedia Britannica 2002—CDROM—Sirenian. Return to text.
- Manatees can apparently hear up to 50 kHz—three times the upper limit of humans: Klishin, V.O. et al., Some characteristics of hearing of the Brazilian manatee, Trichechus inunguis, Aquatic Mammals 16(3):139–144, 1990. [Update, 25 January 2016: For the champion terrestrial mammal’s ultrasound capacity, see The tarsier’s ‘secret speech’}. Return to text.
- Ref. 6, Sirenian—Natural History. Return to text.
- Ref. 6, Sirenian—Classification and paleontology. Return to text.
- Davidheiser, B., The aortic arch, Creation Research Society Quarterly 20(1):15, 1983. Also, evolution-facts.org/c15.htm, 29 October 2003. For the champion terrestrial mammal’s ultrasound capacity, see The tarsier’s ‘secret speech’. Return to text.
- Mumbo jumbo, Creation 24(1):7, 2001. Return to text.