Dugongs are large marine mammals inhabiting warm coastal waters, often referred to as “sea cows” due to their diet. These gentle creatures are strictly herbivorous, primarily grazing on seagrass meadows. They are the only marine mammals that feed exclusively on plants.
Unique Characteristics
Dugongs belong to the order Sirenia, which also includes manatees, but they are the sole living representatives of the family Dugongidae. Their closest modern relative, Steller’s sea cow, became extinct centuries ago. Despite their aquatic lifestyle, dugongs are more closely related to elephants than to other marine mammals like whales or dolphins.
These animals possess a distinctive physical form, typically grey-brown with a robust, cylindrical body. Unlike manatees, dugongs have a fluked, dolphin-like tail and paddle-like forelimbs for maneuvering. Their sharply downturned snout, adapted for seafloor grazing, features sensitive bristles for locating food. Adults measure 2.2 to 3.4 meters in length and weigh 230 to 420 kilograms, living up to 70 years. They communicate using chirps, whistles, and barks.
Habitat and Lifestyle
Dugongs are found in the Indo-Pacific region, inhabiting coastal waters across 40 countries. Their largest populations are concentrated off northern Australia and in the Arabian Gulf. They favor shallow, warm coastal areas with abundant seagrass beds, their primary food source. While primarily found in saltwater, they can tolerate brackish conditions but rarely enter freshwater.
Their diet consists entirely of seagrass, which they uproot using their muscular, downturned snouts. They graze continuously, consuming up to 40 kilograms daily. While usually solitary or in mother-calf pairs, they can form larger groups of several hundred individuals. Dugongs are slow-moving and graceful in the water, navigating using their powerful fluked tails. They have a low reproductive rate, with females giving birth to a single calf every 2.5 to 7 years, nursing them for an extended period.
Conservation Status and Efforts
The dugong is classified as Vulnerable globally by the IUCN Red List of Threatened Species, though some regional populations, such as those in East Africa and New Caledonia, are listed as Critically Endangered or Endangered. Their survival is threatened by human activities and environmental changes. A primary threat is habitat loss and degradation of seagrass meadows, caused by coastal development, pollution, and climate change impacts like rising sea temperatures and extreme weather events.
Accidental entanglement in fishing gear (bycatch) and collisions with boats are major causes of mortality. Historically, hunting for their meat and oil also contributed to population declines. Dugongs play a role as “ecosystem engineers” by grazing seagrass, promoting new growth and maintaining habitat health. Seagrass meadows also prevent coastal erosion, improve water quality, and sequester carbon dioxide.
- International agreements
- Protected marine areas
- Research initiatives
- Community involvement programs to raise awareness and promote safe release from fishing nets
- Phasing out gill nets in some areas to provide protection for dugongs and other threatened marine life