Dugongs: Everything Divers Need to Know About the Sea Cows of Sulawesi
Indonesia is home to some of the most important dugong habitats in Southeast Asia. In North Sulawesi, although sightings are never guaranteed, patient divers and snorkelers can occasionally encounter these remarkable animals grazing in seagrass-rich coastal environments. For those lucky enough to enjoy a glimpse of these gentle giants, encounters can be a once-in-a-lifetime diving experience.
But what exactly are dugongs? What makes them unique? And how can divers make sure interactions with them are responsible and safe? Developing a better understanding of their biology, behavior, and conservation background can not only enrich the experience, but also help support protection for one of the ocean’s most vulnerable mammals.
In this article, we take a closer look at dugongs and provide everything divers need to know about the sea cows of Sulawesi.
What is a Dugong?
The dugong (Dugong dugon) is a marine mammal belonging to the order Sirenia, a group often referred to as ‘sea cows’. Dugongs are the only surviving member of the family Dugongidae and are closely related to manatees, although they differ in both appearance and habitat preferences.
Unlike seals or dolphins, dugongs are fully herbivorous. Adults can reach lengths of 3 meters and weigh up to 500 kg, making them among the largest marine mammals encountered in tropical coastal waters. Their paddle-like forelimbs, streamlined bodies and distinctive fluked tails allow them to move gracefully through shallow marine environments.
Dugongs have evolved over millions of years to specialize in feeding on seagrasses, making them one of the most important herbivores in tropical marine ecosystems.
What Do Dugongs Eat?
Dugongs feed almost exclusively on seagrass. Using their muscular, downturned snouts, they uproot entire plants from the seabed before separating the nutritious leaves and roots from sediment.
Not all seagrasses are equally appealing. Dugongs generally favor fast-growing, nutrient-rich species that are easier to digest. As they feed, they create distinctive furrows or feeding trails across the seabed, which can sometimes be seen by divers exploring healthy seagrass meadows in coastal areas around North Sulawesi.
An adult dugong may consume more than 30 kg of seagrass every day. This grazing behaviour helps maintain healthy seagrass ecosystems by encouraging new growth and preventing dominant species from outcompeting others.
Why Are Dugongs Important to Marine Ecosystems?
Dugongs are often described as ecosystem engineers. By selectively grazing on seagrass beds, they help maintain biodiversity and improve the overall health of these highly productive habitats.
Seagrass meadows provide critical nursery grounds for fish, feeding areas for turtles, and shelter for countless invertebrates. They also play an important role in carbon sequestration, storing significant amounts of ‘blue carbon’ within their sediments.
When dugong populations decline, the structure and composition of seagrass ecosystems can change dramatically. Protecting dugongs therefore helps safeguard entire coastal food webs and contributes to broader marine conservation goals.
To learn how Murex is helping to protect and restore marine habitats in North Sulawesi, click here.
How Long Do Dugongs Live?
Dugongs are relatively long-lived animals, with lifespans that may exceed 70 years under favorable conditions. However, they mature slowly and reproduce infrequently.
Females typically give birth to a single calf after a gestation period of around 13 to 15 months. Calves remain dependent on their mothers for up to 2 years, slowly learning to map out feeding grounds and migration routes before becoming fully independent.
Dugong’s slow reproductive rate means their populations recover very slowly from declines, making them particularly vulnerable to habitat loss and human impacts.
Are Dugongs Endangered?
Dugongs are currently classified as Vulnerable by the International Union for Conservation of Nature (IUCN), although some regional populations are considered endangered or critically threatened.
Across their range, dugongs face a variety of pressures. The greatest threat is the loss and degradation of seagrass habitat due to coastal development, sedimentation, pollution, and destructive fishing practices. You can learn more about how Murex is working to prevent plastic pollution entering marine habitats here.
Additional threats include accidental entanglement in fishing gear, boat strikes, illegal hunting and the increasing impacts of climate change. Extreme weather events, rising sea temperatures and changing ocean conditions can all damage the seagrass meadows upon which dugongs depend.
Because they are highly dependent on healthy coastal ecosystems, dugongs are often regarded as an indicator species for the overall condition of tropical marine environments.
Is It Safe to Dive With Dugongs?
Dugongs are among the gentlest large marine animals encountered by divers. They are usually shy, docile, and generally indifferent to human presence when approached respectfully.
However, responsible wildlife interactions are essential. Divers should maintain a respectful distance, avoid blocking an animal’s path and never attempt to touch, chase, or corner a dugong. Sudden movements, excessive bubbles or aggressive photography techniques can cause stress and alter natural behavior.
The best encounters occur when divers remain still and allow the animal to continue feeding or traveling without interruption. In many cases, curious dugongs will simply carry on grazing while divers watch quietly from a distance.
Where Can Divers Find Dugongs in Indonesia?
Indonesia supports dugong populations across a vast range of coastal habitats, including Papua, Maluku, Nusa Tenggara, Kalimantan, and Sulawesi.
Here in North Sulawesi, we occasionally see dugongs in shallow coastal areas where extensive seagrass meadows occur. These sightings are far less predictable than encounters with reef species such as turtles, octopus, or reef sharks, which is precisely what makes them so special.
Unlike many charismatic marine animals that aggregate seasonally, dugongs tend to move according to food availability and local environmental conditions. Successful sightings therefore rely on a combination of habitat quality, local knowledge, and a healthy dose of luck. If there are any dugongs in the area, our team of experienced local guides will be able to find them and advise you how to dive responsibly when dugongs are nearby.
What Should Divers Do If They Encounter a Dugong?
A dugong encounter is a privilege, not a pursuit. If you are fortunate enough to spot one underwater, the best approach is to slow down, remain calm, and observe from a distance.
Avoid crowding the animal or positioning yourself between it and the surface, and especially its young (calves can sometimes become separated from their mothers when divers get too close). Dugongs must surface regularly to breathe, and any interference with this behavior can cause unnecessary stress.
Underwater photographers should use natural light whenever possible and avoid repeated close approaches. Capturing authentic behavior from a respectful distance generally produces more rewarding images, while ensuring minimal disturbance to the animal.
Why Are Dugong Sightings So Special?
For experienced divers, a dugong sighting represents something deeper than simply adding another species to a life list. It is a reminder that some of the ocean’s most extraordinary creatures thrive not just on coral reefs, but in the often-overlooked seagrass meadows that link coastal ecosystems together.
Protecting these habitats helps ensure that future generations of divers will continue to experience the thrill of seeing one of the ocean’s last remaining sea cows in the wild. By diving with Murex, you can contribute to the preservation of critical habitats for these animals and, if you’re lucky, you just might get to see one in person.
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For more information about diving holidays in North Sulawesi, please visit the Murex Resorts website or get in touch to check rates and availability.
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