the real origin of the mermaid mythology?

Name: dugong (dugong dugon)

Group: marine mammals.

Mate: Length up to 3m, weight up to 570kg.

Eating pattern: Specialist in seagrass communities.

Habitat: Coastal northern Australia from Shark Bay in Western Australia to Moreton Bay near Brisbane (all year), south to Port Stephens in NSW in summer.

Conservation status in Australia: Protected.

Superpower: Meet the only grass-eating mammal that spends its entire life in the sea.

Group of dugongs, including a calf on its mother’s back. Credit: Mandy Etpison

Why would a 400kg marine mammal with a face that only another dugong could love be considered the origin of myths about mermaids and sirens? This link is usually attributed to the dugong’s mammary glands (which have been compared to human breasts) and a long period of close calf dependence. But this link may be more about lust than resemblance. There are stories of dugongs being used by fishermen as surrogate wives in various places in their vast range, which stretches through tropical and subtropical coastal and island waters from East Africa to Vanuatu.

But Australia is the dugong capital of the world. Our northern coastal waters support most of the world’s dugong population and are the most abundant marine mammals in most of this region. The Torres Strait region supports more dugongs than anywhere else.

Indigenous peoples have been hunting dugongs throughout their range for at least 4,000 years. The dugongs are a culturally important species and feature prominently in the art and stories of many coastal peoples, including Aboriginal and Torres Strait peoples of Northern Australia. The coverings of the biblical Tabernacle and the Ark of the Covenant are believed to be made of dugong skin.

The dugong is the only member of the Dugongidae family and one of only four extant sirenians (sea gulls) – the other three species are manatees. Despite being in separate families, manatees and dugongs are remarkably similar. The most noticeable difference is in the shape of the tail: manatees have a round tail like that of a beaver, while a dugong’s tail resembles that of a whale or dolphin. The build of a manatee is more robust than that of a dugong, which looks like a manatee going to the gym! Dugongs look like a cross between a walrus and a dolphin with no dorsal fin.

From a biological perspective, the dugong is very different from other marine mammals. It is the only herbivorous mammal to spend its entire life in the sea. Manatees and dugongs are more closely related to elephants and hyraxes than other marine mammals.

Dugong feeds on seagrass.  Credit sunphol sorakul getty images 1
Dugong feeds on seagrass. Credit: Sunphol Sorakul/Getty Images

The diving performance of dugongs is modest and usually reflects the distribution of the seagrass communities they feed on. While dugongs usually eat seagrass, they also target invertebrates in the high latitudes of their range in winter and have been described as “closet omnivores.”

Dugongs perceive their aquatic environment largely through touch, hydrodynamic reception, and hearing; vision and taste are probably also important to some degree. They have thin sensory hairs all over their bodies that function like the lateral lines of fish.

Dugongs have a long lifespan and breed slowly. The oldest wild dugong to have matured was over 70 years old when she died. Dugongs generally have a calf every few years from a minimum age of about seven years. However, they stop breeding when seagrass is scarce after cyclones, floods or heat waves at sea.

The conservation status of the dugong is variable. It is listed by the IUCN as vulnerable to extinction on a global scale and as endangered, critically endangered or extinct in several of its more than 40 countries. Fortunately, the dugong does not qualify for a listing as endangered in Australia on a national scale. Nevertheless, they are protected as migratory and marine species. However, there are population concerns in some regions, particularly the urban cost of the Great Barrier Reef.

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