Dugong: Discover the Gentle Sea Cow of the Ocean
Peter Letts Mar 04, 2025
DUGONG BIOLOGY, HABITAT & CONSERVATION
Dugong Facts: Meet the Gentle Sea Cow
Meet Dugong dugon: a fully marine, seagrass-grazing mammal shaped by shallow coastal waters, a remarkably long life and one of the slowest reproductive cycles in the ocean.
A marine mammal built around seagrass
A dugong is not a fish, a whale or a manatee. It is the only living species in the family Dugongidae and one of just four living sirenian species.
Dugongs spend their entire lives at sea. Their downturned, bristled muzzle is designed to crop and uproot seagrass, while a whale-like fluked tail moves their heavy body through bays, lagoons and coastal channels. They may appear unhurried, but they are powerful wild animals capable of travelling long distances between feeding areas.
Hoping to see one in the wild? Our guide to where and how people can swim with dugongs explains which experiences are genuine, what is permitted and why every sighting must remain animal-led.
What is a dugong?
The scientific name is Dugong dugon. Dugongs belong to the mammalian order Sirenia, alongside three living manatee species. Their closest living relatives are manatees; elephants are more distant relatives within the same broad evolutionary lineage.
It breathes air
A dugong must surface to breathe through nostrils near the top of its snout. In rippled or murky water, observers may see only the muzzle, a curve of back and then the tail.
It is fully marine
Unlike manatees, dugongs remain in salt water. They use shallow bays and seagrass banks but can cross deeper channels and travel far along a coast.
It is a specialist grazer
A muscular upper lip and sensitive bristles help the animal select, crop and sometimes uproot seagrass from soft sediment.
It recovers slowly
Late maturity, one calf at a time and long gaps between births mean a population cannot quickly replace animals lost to nets, vessels or habitat failure.
Dugong vs manatee: what is the difference?
Both are slow-moving, plant-eating sirenians, so the confusion is understandable. The tail and habitat are the quickest clues.
| Feature | Dugong | Manatee |
|---|---|---|
| Tail | Two pointed flukes, similar in outline to a whale or dolphin tail | Broad, rounded paddle-shaped tail |
| Water | Entirely marine | Marine, brackish and freshwater habitats, depending on the species |
| Range | Warm coastal waters of the Indian and western Pacific oceans | Atlantic-facing Americas, the Amazon basin and West Africa |
| Living species | One: Dugong dugon | Three recognised manatee species |
What does a dugong look like?
Most adults are about 2.5 to 3 metres long and weigh several hundred kilograms. Their thick, streamlined body tapers towards the tail, and the head angles down towards the seabed.
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Downturned muzzle
A broad upper lip and short bristles help find and handle seagrass.
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Fluked tail
The tail moves up and down for propulsion, while the foreflippers steer and stabilise.
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No dorsal fin
This helps distinguish a surfacing dugong from a dolphin at a distance.
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Individual markings
Scars, pale patches and other marks can help researchers recognise individuals in clear photographs.
Where do dugongs live?
Dugongs occur across a vast but fragmented Indo-Pacific range, from the coast of East Africa and the Red Sea through South and Southeast Asia to northern Australia and Vanuatu. They are not spread evenly within that range: suitable seagrass, shelter, depth and safe routes between feeding areas determine where they can live.
Shallow and sheltered—but not exclusively
Bays, lagoons and the lee of islands often provide productive seagrass and protection from heavy waves. Dugongs can also use deeper offshore water where a broad, shallow continental shelf provides suitable habitat.
A home range can be much larger than one bay
Some animals stay within a relatively small area for a time; others make long coastal movements as seagrass, water temperature and conditions change. A sighting does not prove permanent residency.
Not seeing one proves very little
Dugongs spend much of an observation period underwater and can change direction below the surface. Wind, glare, turbidity and uneven search effort all influence sightings.
One of the species’ most important refuges
In Australia, dugongs occur in northern coastal waters from around the Queensland–New South Wales border to Shark Bay in Western Australia. Important habitats include Torres Strait, the Great Barrier Reef, the Gulf of Carpentaria, the Northern Territory coast, the Kimberley, Pilbara and Shark Bay.
Australia supports some of the world’s largest remaining dugong populations, but that national importance should not be confused with uniform security. The Reef Authority reports concern about declines along Queensland’s urban coast south of Cooktown, while remote northern areas appear more stable.
What do dugongs eat?
Dugongs feed mainly on seagrass, especially soft, fast-growing species such as Halophila and Halodule. Occasional algae or small invertebrates have been recorded, so “almost entirely herbivorous” is more accurate than treating every animal’s diet as absolutely plant-only.
A large animal can consume up to around 30 kilograms of seagrass in a day. The exact amount depends on body size, plant species, water content and nutritional quality.
How feeding works
The muzzle presses into the seabed while the upper lip crops leaves or pulls up whole plants. This can leave winding feeding trails through a meadow. Those trails show recent use, but they cannot reveal how many dugongs fed there or where the animals went afterwards.
Grazing shapes the meadow
Dugongs alter plant height and species composition, disturb sediment, recycle nutrients and can disperse seagrass seeds. The effect varies with habitat and grazing intensity.
Meadows support whole communities
Seagrass provides food and nursery habitat for turtles, fish and invertebrates while stabilising sediment and improving coastal water quality.
Habitat loss affects reproduction
Females need enough energy to mature, conceive and nurse a calf. Poor seagrass condition can therefore affect much more than the next meal.
How do dugongs swim, communicate and socialise?
Dugong behaviour is flexible. Many sightings involve one animal, a mother and calf, or a small group; larger aggregations can form where food is concentrated or during social activity.
Swimming
The tail provides propulsion with an up-and-down movement. Dugongs often travel slowly while feeding, but they can accelerate when alarmed. A long dive or abrupt turn can be a sign that an observer is too close.
Breathing
They surface through nostrils on top of the snout, then may remain underwater for several minutes. An animal must never be crowded, crossed or separated from the surface.
Communication
Researchers have recorded chirps, whistles, squeaks and bark-like calls. Sound is important between mothers and calves and during other close-range social interactions.
Disturbance
A dugong does not need to flee dramatically to be affected. Stopping feeding, changing direction, lengthening a dive or leaving a patch are all reasons to create more space.
Dugong calves, reproduction and lifespan
Dugongs are built for longevity, not rapid population growth. Timings vary among animals and regions, but every stage is slow compared with many marine species.
Years before females breed
Age at sexual maturity varies with nutrition, population and local conditions.
Months of pregnancy
A female normally gives birth underwater to a single calf.
Months of nursing
The calf suckles from mammary glands behind its mother’s flippers and remains closely dependent on her.
Years between calves
That interval can lengthen when food or conditions are poor.
Even under ideal conditions, the Reef Authority estimates a maximum possible population increase of only about 5% a year. Added mortality among breeding females can therefore outweigh reproduction and take decades to reverse.
What animals eat dugongs?
Adult dugongs are large enough that relatively few predators can take them. Large sharks, saltwater crocodiles and killer whales may prey on dugongs, with calves and smaller animals more vulnerable.
Natural predation is part of the ecosystem. The greater conservation concern is preventable human-caused mortality—particularly entanglement, vessel strike, hunting and the loss of seagrass habitat.
Why are dugongs vulnerable?
The dugong is globally assessed as Vulnerable on the IUCN Red List, but the global label hides major regional differences. The 2025 CMS global assessment describes relatively secure strongholds alongside small, isolated or severely depleted populations. In many places, the true trend is still poorly known.
Fishing nets and marine debris
Dugongs can become entangled and drown because they must reach the surface to breathe. Gillnets are a major concern across much of the range.
Vessel strikes
Shallow feeding areas overlap with boating routes. Dugongs can be difficult to see before they surface, particularly in glare or turbid water.
Seagrass loss
Coastal development, dredging, sediment, nutrient runoff, pollution and physical damage can reduce the food and shelter available.
Climate and severe weather
Marine heatwaves, floods and intense cyclones can damage or bury seagrass. Animals may travel farther, lose condition or face more risks while searching for food.
Hunting and direct take
Rules and cultural contexts differ across the range. Where mortality exceeds the slow reproductive rate, a small population can decline quickly.
Repeated disturbance
Close vessels, chasing and poorly managed tourism can interrupt feeding, separate animals or push them away from valuable habitat.
Protect the animal and the meadow beneath it
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Reduce bycatch through safer fishing practices, attended nets and locally appropriate restrictions.
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Protect and monitor seagrass, water quality and movement corridors before coastal development proceeds.
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Slow vessels in shallow dugong habitat and train operators to recognise animals and feeding areas.
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Support long-term, community-led monitoring that records search effort as well as successful sightings.
How to observe a dugong responsibly
Wildlife presence is not the same as a safe, legal or bookable tourism experience. Rules differ by country, marine park, vessel type and whether a mother and calf are present. Follow the local law and the most protective guidance available.
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Slow down and keep the vessel’s path predictable.
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Never chase, touch, feed, surround or block a dugong’s route to the surface.
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Give mothers and calves substantially more space.
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Do not anchor on, walk through or damage seagrass.
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If the animal changes behaviour, increase distance immediately.
Current international guidance specifically discourages planned in-water interactions with sirenians and recommends against scuba interaction. If a dugong appears during an ordinary dive, remain calm, do not descend towards it and never follow it.
Read the Vanuatu dugong encounter guidelinesFrequently asked questions about dugongs
Is a dugong a fish?
No. A dugong is an air-breathing marine mammal. It gives birth to live young and nurses its calf with milk.
Are dugongs and manatees the same?
No. They are close relatives in the order Sirenia. A dugong is fully marine and has a fluked tail; a manatee can use fresh, brackish and marine water and has a rounded paddle tail.
Where do dugongs live?
Dugongs live in warm coastal waters of the Indian and western Pacific oceans, from East Africa and the Red Sea to northern Australia and Vanuatu. Their distribution is patchy because they depend on suitable seagrass habitat.
What do dugongs eat?
They feed mainly on seagrass, often favouring soft, fast-growing species. A large dugong can consume up to around 30 kilograms in a day.
How big do dugongs grow?
Most adults are about 2.5 to 3 metres long. A fully grown dugong can weigh around 400 kilograms, although size varies among individuals and regions.
How long do dugongs live?
Dugongs may live for 60 to 70 years, and an animal of 73 years has been recorded. Many die younger because of natural and human-caused pressures.
How often does a dugong have a calf?
A female usually gives birth to one calf after a pregnancy of about 13 to 15 months. Under good conditions, three to seven years may pass between calves.
What predators eat dugongs?
Large sharks, saltwater crocodiles and killer whales may prey on dugongs. Calves are more vulnerable than healthy adults.
Are dugongs endangered?
The species is globally listed as Vulnerable on the IUCN Red List. Some regional populations are more severely depleted, while major Australian and Persian Gulf strongholds are comparatively secure.
Can you swim with dugongs?
Only in limited places and only when local law, animal welfare and an authorised guide allow it. A dugong can never be guaranteed. Compare where and how responsible wild encounters may be possible, then follow the Vanuatu dugong encounter guidelines if planning a visit there.
How this article was checked
This page was last reviewed on against current government and international conservation material, plus the published North Efate survey.
- CMS: A Global Assessment of Dugong Status and Conservation Needs (2025)
- CMS Dugong MOU: dugong biology and conservation FAQs
- Australian Government DCCEEW: Dugongs
- Great Barrier Reef Marine Park Authority: Dugong
- Vanuatu Environmental Science Society: Report on Survey of Dugongs (2022)
- CMS: Guidelines on Recreational In-water Interactions with Marine Wildlife
From dugong facts to a responsible Vanuatu dive holiday
Each guide below answers a different question. Follow the sequence to compare genuine wild possibilities, understand the local evidence and know how to behave before considering travel.
Where can people swim with dugongs?
Compare the world’s main destinations and the difference between a swim, snorkel and incidental dive sighting.
Where are dugongs found in Vanuatu?
Review the country-wide picture, including Havannah Harbour, Santo, Malekula, Epi and other reported areas.
What supports the Havannah Harbour claim?
Examine the seagrass habitat, published survey, local knowledge and limits of the available evidence around Moso Island.
How should a dugong be encountered?
Read the Vanuatu rules for swimmers, snorkellers, divers, boats, photographers and drones.
Plan a Vanuatu diving holiday with honest expectations
Start with the broader Vanuatu diving guide, then compare the two Abyss itineraries below.
These are diving holidays, not guaranteed dugong encounters. Dugongs are present in Havannah Harbour and a wild sighting is genuinely possible, but it is never assured or sold as an included encounter.
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