The dugong (Dugong dugon) is the only living member of the family Dugongidae and one of the ocean’s most distinctive herbivorous mammals. Often called a “sea-cow,” it is a specialist grazer on seagrass meadows in shallow tropical and subtropical coastal waters across the Indian Ocean and western Pacific. By cropping and sometimes uprooting seagrasses, dugongs help shape meadow structure and can promote regrowth—earning them the nickname “gardeners of the seagrass bed.”
Compared with manatees, dugongs have a fluked, whale-like tail and a more strongly downturned snout adapted for feeding along the seafloor. They reproduce slowly and depend heavily on healthy seagrass habitat, which makes them vulnerable to habitat loss and human disturbance. Seagrass decline, entanglement in fishing gear, vessel strikes and illegal hunting have all contributed to conservation concern in parts of their range.
Taxonomy and naming
Dugongs are mammals (Order Sirenia) in the family Dugongidae and the genus Dugong. The dugong is the only living species in this genus. The word “dugong” is derived from a Malay/Philippine-language term often glossed as “lady of the sea,” and it has long been associated with maritime folklore.
While dugongs have sometimes been linked to “mermaid” stories, they are a real, seagrass-dependent marine mammal with important ecological roles in coastal ecosystems.
Physical characteristics
Dugongs are large, robust animals. Adults typically measure about 2.4–3.3 m in length and often weigh roughly 250–400 kg, with some individuals larger. Skin colour is usually grey to brownish-grey and often shows scars and mottling. The head is relatively small, with small eyes and no external ear pinnae.
The most distinctive feature is the thick, downturned snout with a mobile upper lip covered in stiff bristles, used to probe, grasp and uproot seagrass. The forelimbs are paddle-like flippers for steering and support. The tail is a fluked, dolphin/whale-like shape—an easy way to distinguish dugongs from manatees. Adult males may develop short, tusk-like incisors used mainly in social interactions.
Distribution and habitat
Dugongs occur across tropical and subtropical coastal waters of the Indian Ocean and western Pacific, with records from East Africa and the Red Sea/Persian Gulf through South and Southeast Asia to northern Australia and parts of the western Pacific islands. They are strongly tied to shallow seagrass meadows in protected bays, lagoons, straits and behind reef systems where the seafloor is suitable for seagrass growth.
Movements can be seasonal and are closely linked to seagrass availability and water conditions. Because seagrass meadows often overlap with human coastal development, long-term habitat protection and careful management are central to dugong conservation.
Behaviour and lifestyle
Dugongs often feed during the day or around dusk, and in some areas they may feed at night to reduce disturbance. They are usually seen alone or in small, loose groups such as mother–calf pairs, though larger aggregations can form where food is abundant.
They must surface regularly to breathe, with surfacing intervals ranging from minutes to longer depending on activity level. Dugongs are not fast swimmers, but they can travel steadily over long distances. When disturbed, they may move away quickly or shift into deeper water.
Diet
Dugongs are highly specialized herbivores that feed almost entirely on seagrasses. They crop leaves and can also uproot plants to eat rhizomes and roots, leaving characteristic feeding trails on the seabed. Preferred seagrass species vary by region, and dugongs often select tender, nutritious plants that are easier to digest.
Moderate grazing and sediment disturbance can help maintain meadow dynamics, but large-scale seagrass loss can quickly reduce food supply and affect body condition and reproduction.
Reproduction and life cycle
Dugongs have a slow reproductive rate. Gestation is about 13–15 months and females typically give birth to a single calf. Calves nurse for a year or more, and the mother–calf bond can last for an extended period. Inter-birth intervals are often several years, which means population recovery is slow after declines.
Sexual maturity takes many years. Longevity is measured in decades and is often suggested to reach around 50–70 years. This life-history strategy makes dugongs very sensitive to persistent human-caused mortality such as entanglement and boat strikes.
Relationship with humans
Dugongs are culturally significant in many coastal communities and are sometimes associated with maritime folklore. Today, they are also valued as indicators of seagrass meadow health. Responsible viewing should minimize disturbance: slow speeds, keeping distance and avoiding prolonged pursuit—especially around mother–calf pairs.
Historically, dugongs were hunted for meat and oil in some regions. Modern conservation often combines legal protection, marine protected areas and community-based management to reduce illegal hunting and to address threats linked to fishing and vessel traffic.
Conservation status and threats
The dugong is generally listed as Vulnerable (VU) globally. Major threats include seagrass loss and degradation (coastal development, turbidity, storms and marine heatwaves), bycatch and entanglement in fishing gear (especially gillnets), vessel strikes, illegal hunting and pollution including plastics and chemical contaminants.
Effective conservation focuses on protecting and restoring seagrass meadows, reducing bycatch risk through gear and spatial management, establishing low-speed zones and safer vessel routes in key habitat and maintaining long-term monitoring (aerial/drone surveys, acoustics and tagging) to understand population trends and habitat use.
