Dugongs, large grey marine mammals gracefully navigating warm coastal waters, often spark curiosity. Their substantial size can lead to misunderstandings about their nature. This article examines dugong behavior and interactions with humans to address whether they are dangerous.
Dugong Basics: What Are They?
Dugongs (Dugong dugon) are the sole living representatives of the family Dugongidae, belonging to the order Sirenia, which also includes manatees. They have a large, streamlined grey body with a fluked, dolphin-like tail. Short, paddle-like front flippers aid steering, and a distinctive downturned snout with sensitive bristles is adapted for foraging.
These animals typically measure 2.4 to 4 meters (8 to 13 feet) in length and weigh 230 to 420 kilograms (500 to 925 pounds). Unlike manatees, which can inhabit freshwater, dugongs are strictly marine, living in shallow, protected coastal areas, bays, and mangrove channels across the Indo-West Pacific. Dense bones help them maintain buoyancy.
Dugongs are herbivorous, earning them the nickname “sea cows” due to their diet of seagrass. They use their strong, flexible upper lip to consume large quantities, often grazing up to 30 kilograms (66 pounds) daily. Their feeding habits, which involve uprooting seagrass, are important for maintaining seagrass meadows. Dugongs are slow-moving and peaceful.
Are Dugongs a Threat to Humans?
Dugongs are not considered dangerous to humans. Their behavior is shy and non-aggressive, with their primary instinct being to retreat when disturbed. There are no recorded instances of unprovoked attacks by dugongs on humans. Their large size might lead some to perceive them as a threat, but their actions are consistently non-confrontational.
These animals lack natural defensive mechanisms against humans, possessing no claws, formidable teeth, or grasping appendages. While adult dugongs have few natural predators, younger individuals can be preyed upon by large sharks, saltwater crocodiles, and killer whales. Their slow movement also indicates a lack of aggressive defense.
Any potential harm from a dugong would likely stem from accidental circumstances, such as unintentional collisions with boats, rather than deliberate aggression. Male dugongs use their small tusks for intraspecific fighting during mating season, not as a weapon against other species. Reports of dugongs bumping canoes are often linked to specific behaviors like breeding, not aggression. Their seagrass diet means they have no predatory interest in humans.
Coexisting with Dugongs: Safe Practices and Conservation
Responsible human behavior is important for protecting dugongs and ensuring safe interactions. If encountered in the wild, maintain a respectful distance: at least 20 meters (65 feet) for swimmers and 50 meters (164 feet) for boats. Avoid sudden movements, refrain from feeding or chasing them, and never place yourself between a mother and her calf. Do not obstruct a dugong’s path to the surface, as they need to breathe regularly.
While dugongs pose no threat to humans, human activities significantly threaten their populations. These marine mammals are listed as vulnerable globally on the IUCN Red List. Major threats include habitat loss and degradation, primarily from the destruction of seagrass meadows due to coastal development and pollution.
Dugongs are also susceptible to boat strikes due to their slow movement and habit of feeding near the surface. Accidental entanglement in fishing gear, especially gillnets, is another cause of mortality, as dugongs can drown if trapped. Their long lifespan, which can exceed 70 years, combined with a slow reproduction rate—a single calf every three to seven years—makes them vulnerable to population declines. Supporting conservation efforts and adhering to responsible observation guidelines are important for their continued survival.