The dugong is a large marine mammal often referred to as a “sea cow,” a nickname earned from its slow, grazing existence feeding on underwater grasses in warm, coastal waters. Belonging to the order Sirenia, alongside manatees, the dugong is widely viewed as a gentle giant of the ocean. This perception stems from its docile nature and herbivorous diet. Investigating the animal’s biology and behavior provides a clear answer to whether this massive animal poses a risk to human swimmers, boaters, and divers.
Defining the Dugong and Its Temperament
The dugong’s physical makeup is adapted for a purely plant-based life, setting it apart from predatory marine mammals. As the only strictly marine herbivore, its diet consists almost entirely of seagrass, which it locates using sensitive bristles on its muscular upper lip. These animals can grow up to three meters long and weigh over 400 kilograms, yet they lack offensive features like sharp teeth or claws. They possess simple, peg-like molar teeth designed only for grinding vegetation.
Their movements are typically slow and deliberate, moving through the water at about 10 kilometers per hour. A dugong’s primary defense mechanism is avoidance, as they are naturally shy and elusive creatures. They rely on vocalizations, such as chirps and whistles, and physical touch for communication. This peaceable existence, focused entirely on grazing, establishes the dugong as an inherently non-aggressive species.
Assessing the Risk to Humans
Dugongs are fundamentally non-aggressive toward humans, and there are no documented cases of intentional attacks. Their shy temperament means they generally flee or attempt to avoid human presence. Any risk a dugong might present is purely accidental, resulting from the animal’s sheer size and power when startled or disturbed. A large animal panicking when cornered or attempting to escape can cause injury through an unintended collision.
The most powerful part of the animal is its fluked, dolphin-like tail, which it uses to propel its massive body. Guidelines advise staying at least two meters away from the tail to avoid being inadvertently struck if the animal suddenly moves. Injuries that have occurred are typically limited to minor trauma or bruising from an animal accidentally bumping a swimmer while rapidly moving away.
The idea of a dugong intentionally attacking a person is unsupported by decades of observation. Their non-predatory diet and instinct to avoid human contact make them harmless in the vast majority of interactions. Injury is nearly always a defensive or panicked action in response to a direct human provocation or disturbance.
Habitat and Context of Human Encounters
Dugongs inhabit warm, coastal waters across the Indo-Pacific region, favoring shallow areas like protected bays and mangrove channels. These environments are ideal because they support the dense seagrass meadows that form the dugong’s food source. This preference for shallow habitats means their range frequently overlaps with areas heavily utilized by humans for recreation, fishing, and coastal development.
The intersection of dugong feeding grounds and human activity creates the potential for frequent encounters. Clear guidelines have been developed in many regions to ensure safe interactions. These rules recommend minimizing noise and splashing when swimming or diving near a dugong to avoid startling the animal.
Boaters are advised to maintain a distance, often 50 meters or more, and to travel at slow speeds in known seagrass areas. It is important never to block a dugong’s path to the surface, as they are air-breathing mammals that must regularly rise to breathe. Adhering to these simple practices ensures the animal remains undisturbed.
Protecting the Gentle Giant
Despite the dugong’s immense size, the animal is the vulnerable party in almost all human interactions. The species is currently listed as vulnerable globally, with many populations experiencing severe declines. This vulnerability is partly due to its slow life history; females reach sexual maturity late and typically produce a single calf every three to seven years, making population recovery extremely slow.
The primary threats to dugongs are entirely human-caused. Accidental entanglement in fishing gear, particularly gillnets, is a major cause of death, as these air-breathing animals can quickly drown when trapped underwater. Vessel strikes from fast-moving boats are another significant threat, often causing severe trauma or propeller cuts.
Habitat destruction also poses a continuous problem, with pollution, coastal development, and climate change impacting the health of essential seagrass meadows. Protecting the dugong involves managing these human impacts, such as establishing go-slow zones for vessels and protecting the integrity of their seagrass ecosystems.