Dugong
The dugong is a large, marine herbivorous mammal belonging to the order Sirenia, making it a close relative of manatees. Often referred to as the “sea cow,” the dugong grazes on underwater seagrass meadows in warm coastal waters of the Indo-Pacific region. As the only surviving member of the Dugongidae family, this gentle, slow-moving creature has been a key part of marine ecosystems for millions of years but now faces numerous conservation threats.
Meet the Dugong
Classification
Dugongs are robust marine mammals with streamlined, fusiform bodies adapted for an aquatic lifestyle. They typically measure between 2.5 and 4 meters (8 to 13 feet) in length and weigh between 250 and 900 kg (550 to 2,000 lbs). Unlike manatees, dugongs have a distinct fluked tail similar to that of dolphins, which helps propel them gracefully through the water.
Their skin is thick, smooth, and usually grayish-brown, often covered in algae and scars from encounters with boats or predators. Dugongs have large, paddle-like forelimbs that they use for steering and maneuvering, but they lack hind limbs. Their broad, downturned snouts are adapted for grazing on seagrass, with bristly, sensitive whiskers (vibrissae) that help them detect food on the ocean floor.
Where Does the Dugong Live?
Biogeographic Realm: Marine
Continents: Africa, Asia, Oceania
Subcontinents: East Africa, North Africa, East Asia, Southeast Asia [Show all subcontinents]
Countries: Australia, Christmas Island, Bahrain, Brunei [Show all countries]
Habitats (IUCN): Marine Neritic, Marine Intertidal
Dugongs inhabit warm, shallow coastal waters throughout the Indo-Pacific region, ranging from the eastern coast of Africa and the Red Sea to the waters of Australia, Southeast Asia, and the Pacific Islands. The largest remaining populations are found in Australia, particularly in the Great Barrier Reef and Shark Bay, where seagrass beds remain relatively intact.
These marine mammals prefer sheltered bays, mangrove channels, and estuaries with extensive seagrass meadows, their primary food source. They tend to avoid deep or open waters and are highly sensitive to habitat degradation caused by human activities such as coastal development, dredging, and pollution.
What Do Dugongs Eat?
Dugongs are strict herbivores, feeding almost exclusively on seagrass. Using their downturned snouts and muscular upper lips, they uproot entire seagrass plants, consuming both the leaves and roots. Their diet consists primarily of seagrass species rich in nutrients, but they occasionally ingest algae and other plant material.
A dugong’s feeding behavior plays a vital role in maintaining healthy seagrass ecosystems. By selectively grazing on certain species, they promote seagrass diversity and growth. However, seagrass beds are highly sensitive to environmental disturbances, and any degradation in their habitat directly threatens dugong populations.
What Eats Dugongs? – Predators & Natural Enemies
Adult dugongs have few natural predators due to their large size, but they are occasionally targeted by sharks, such as tiger sharks (Galeocerdo cuvier), and saltwater crocodiles (Crocodylus porosus). Juveniles are more vulnerable and may fall prey to these predators, as well as orcas (Orcinus orca).
Humans pose the most significant threat to dugongs. Historical overhunting for their meat, oil, and hides drastically reduced their populations in many regions. Today, incidental bycatch in fishing nets, boat strikes, habitat destruction, and climate change continue to threaten their survival.
Behavior & Lifestyle
Dugongs are slow-moving, gentle creatures that spend most of their time grazing on seagrass or traveling between feeding grounds. They are generally solitary but may be found in small, loose groups, particularly mothers with calves or during mating season. Social bonds between dugongs are not as strong as those seen in other marine mammals, but they do communicate using a variety of vocalizations, including chirps, whistles, and barks. These sounds help them locate each other in turbid waters and may play a role in mating and mother-calf communication.
Dugongs have relatively poor eyesight but compensate with an acute sense of hearing and highly sensitive vibrissae that help them detect underwater food. Their vibrissae are located around their upper lips and act as tactile sensors, allowing them to identify the texture and movement of seagrass beds. This adaptation is crucial for their survival, as they often forage in murky waters where visibility is limited.
Dugongs are capable of holding their breath for several minutes but must surface regularly to breathe, usually every 3 to 12 minutes. When resting, they can stay submerged for longer periods, using minimal movement to conserve energy. They tend to rest near the sea floor, occasionally rising to the surface for air before sinking back down.
Despite their bulk, they are graceful swimmers, using their powerful tails to move through the water with ease. Their movements are typically slow and deliberate, but they can make quick bursts of speed if startled or threatened. Dugongs are also known to engage in playful behaviors, including rolling, spinning, and rubbing against the seafloor or objects like coral and seagrass patches.
Unlike many marine mammals, dugongs do not perform elaborate social interactions or long-distance migrations. However, they do exhibit some movement patterns related to food availability and seasonal changes. In areas where seagrass beds decline seasonally, dugongs may travel significant distances to find new feeding grounds. Tracking studies have shown that some individuals can cover hundreds of kilometers in search of suitable habitats.
How Do Dugongs Reproduce?
Dugongs have a slow reproductive rate, which contributes to their vulnerability. Mating occurs year-round, but peaks during certain seasons depending on the region. Males compete for females through displays of strength and aggressive behavior. Once pregnant, a female undergoes a gestation period of about 13 to 15 months before giving birth to a single calf.
Newborn calves are about 1.2 meters (4 feet) long and weigh around 30 kg (66 lbs). They remain close to their mothers for up to two years, nursing and learning essential survival skills, including how to find and graze on seagrass. Female dugongs give birth only once every 3 to 7 years, making population recovery slow if numbers decline.
Are Dugongs Endangered? – Conservation Status & Threats
The dugong is classified as Vulnerable by the International Union for Conservation of Nature (IUCN). Although they are still found across their historical range, their populations have declined significantly due to habitat loss, accidental entanglement in fishing gear, hunting, and boat collisions.
Seagrass habitat destruction, caused by coastal development, pollution, and climate change-induced events such as cyclones and rising sea temperatures, is one of the greatest threats to dugongs. Without healthy seagrass meadows, their primary food source, dugong populations cannot be sustained.
Conservation efforts include marine protected areas, stricter fishing regulations, and habitat restoration projects aimed at preserving seagrass ecosystems. Countries like Australia and the Philippines have implemented dugong conservation programs, while international agreements such as the Convention on Migratory Species (CMS) aim to protect them across national borders.
Despite these efforts, dugongs remain at risk, and continued conservation action is necessary to ensure their long-term survival in the wild.
