The dugong is a unique marine mammal, an aquatic herbivore that navigates the warm, shallow waters of coastal regions. Often referred to as “sea cows,” these gentle creatures hold a distinctive position within ocean ecosystems. They are the only surviving species in their family, Dugongidae, making their presence in the marine world particularly special.
Physical Characteristics and Distinct Behaviors
Dugongs possess a large, cylindrical body, reaching 2.2 to 3.4 meters (7 to 11 feet) in length and weighing 230 to 420 kilograms (500 to 925 pounds). Their paddle-like forelimbs are used for balance and turning. A powerful, whale-like fluked tail propels them through water with graceful, slow movements. This fluked tail distinguishes them from manatees, which have a rounded, paddle-shaped tail.
Their snout is broad and downward-pointing, equipped with thick, sensitive bristles that aid in detecting and manipulating food. Unlike manatees, which may have nails on their flippers, dugongs do not. Adult male dugongs, and some older females, can develop small tusks, used by males during mating season for fighting. Dugongs have poor eyesight but good hearing, relying on other senses to navigate.
Habitat and Diet: The Gentle Grazers
Dugongs inhabit warm, shallow coastal waters across the Indo-Pacific region. Their presence is closely tied to the availability of seagrass meadows, which serve as their primary food source. They are the only exclusively herbivorous marine mammals, consuming up to 50 kilograms (110 pounds) of seagrass daily.
They use their specialized downward-pointing snout and bristly lips to graze on seagrass. This grazing behavior earns them the nickname “sea cows.” Seagrass meadows are not just a food source; they are also a habitat for many other marine species and contribute to coastal protection and water quality. The health of dugong populations often indicates the overall health of these seagrass ecosystems.
Conservation Status and Threats
The dugong is currently classified as “Vulnerable” on the IUCN Red List of Threatened Species. While Australia hosts the largest population, with over 100,000 individuals, populations in other regions, such as East Africa and New Caledonia, are critically endangered or endangered. In East Africa, fewer than 250 mature individuals remain, and in New Caledonia, there are under 900.
Habitat loss and degradation of seagrass beds, due to coastal development, pollution, dredging, and climate change, threaten dugongs. They are also vulnerable to accidental entanglement in fishing gear, which can lead to drowning, and collisions with boats. The dugong’s long lifespan (up to 70 years) and slow reproductive rate (females typically give birth to a single calf every 3 to 7 years) make their populations slow to recover from these impacts.