The Seagrass Grazer
Dugong
Gentle, slow-moving, and sometimes mistaken for mermaids, dugongs glide through shallow waters, quietly sculpting the seagrass meadows that feed them and so many others.
Introduction
The Role Player We Can’t Afford to Lose
Dugongs are more than peaceful herbivores—they’re ecosystem sculptors. As they graze on seagrass beds, they shape the structure and health of these underwater meadows, helping them stay productive and resilient. Without dugongs, seagrass ecosystems can become overgrown, unbalanced, and far less diverse.
Fun Fact
Dugongs are closely related to elephants—not whales or dolphins—and can live for over 70 years in the wild.
Biology & Behaviour
Gentle Giants of the Seagrass Plains
Dugongs (Dugong dugon) are the only strictly marine herbivorous mammal. With paddle-like flippers, a fluked tail like a dolphin’s, and a large, downturned snout, they’re perfectly built for grazing seagrass along the ocean floor.
They use their sensitive, bristled snouts to uproot entire seagrass plants, leaving furrowed trails behind them like underwater lawnmowers. Dugongs are mostly solitary or form small groups, feeding for hours each day and surfacing every few minutes to breathe.
Mothers give birth to a single calf after a long gestation period (around 13–15 months), and calves may stay with their mothers for up to 18 months, learning where and how to feed. Dugongs have low reproductive rates, which makes population recovery especially slow.
Conservation & Threats
Grazers in Peril
Dugong populations are declining across much of their range due to:
Boat strikes
and entanglement in fishing gear
Coastal development
which destroys seagrass beds
Water pollution
especially from sediment and agricultural runoff
Climate change
which impacts seagrass growth and availability
Dugongs are listed as Vulnerable by the IUCN. In some areas, they are already extinct or on the brink.
Did you know?
Dugongs have poor eyesight but an extraordinary sense of touch—they can feel vibrations and use their stiff facial bristles to find the tastiest seagrass.
How Do They Connect the Ecosystem?
Gardeners of the Seafloor
Dugongs are ecosystem shapers. Their selective grazing:
- Encourages new seagrass growth
- Prevents dominance by a single species
- Increases meadow biodiversity
- Enhances nutrient cycling within the sediment
By uprooting and feeding on seagrass, dugongs create space for other plants and animals, supporting a dynamic and diverse habitat that’s more resilient to disturbance.
Hope & Action
Saving the Seagrass Grazer
Conservation efforts to protect dugongs often go hand in hand with seagrass restoration:
- Marine protected areas safeguard both dugongs and their food source
- Speed restrictions in shallow areas reduce boat strikes
- Better water quality management helps seagrass flourish
- Community involvement and Indigenous stewardship play a key role in dugong protection, especially in Australia and Southeast Asia
By protecting dugongs, we also protect the habitats they help maintain.
Species ID Card
Dugong
Want to take this species with you? Download our printable ID card to keep learning, share with others, or use in your classroom or ocean journal.
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