Dugong: where and when to see them

The dugong is a fully marine herbivorous mammal associated with shallow seagrass habitats across parts of the Indo-Pacific. Its heavy body, downturned muzzle and fluked tail reflect a life spent feeding and travelling in coastal waters, not on land. Populations are often fragmented, and apparently suitable bays may hold very few animals. Seagrass loss, fishing-gear entanglement, vessel strikes and hunting have contributed to declines across much of its range.

Size

2.4–3 m long

Weight

250–450 kg

Lifespan

Not reliably established

Status

Vulnerable

Dugongs often occur alone or in small parties, although larger gatherings can form where feeding conditions are favourable. They uproot or crop seagrass with muscular lips, sometimes leaving recognizable feeding trails. Mothers maintain long associations with their calves, which learn movements and feeding areas while accompanying them. At the surface, a quiet breath and a small section of back may be all that is visible before the animal submerges again. Dugongs are long-lived, with individuals potentially reaching 70 years of age, reflecting their slow reproductive rate. Females give birth to a single calf after a gestation period of about 13 months. Social structures can vary, with some populations exhibiting more solitary habits while others form larger, temporary aggregations when food is abundant.

• The dugong is the only living member of the family Dugongidae.
• Its closest extinct relative was Steller's sea cow.
• Adult males commonly develop visible tusks from enlarged upper incisors.
• Females usually produce a single calf, with long intervals between successful births.

There is no single viewing season across the dugong's broad range. Calm water, clear visibility and locally suitable tides matter most for distant shore or deck observation. Regional dry-season travel windows should not be mistaken for breeding seasons or confirmed presence. In tropical regions like northern Australia and Southeast Asia, the dry season often coincides with calmer seas, improving viewing conditions from boats. However, dugong presence can also be influenced by the availability of flowering seagrass, which varies seasonally. Understanding local seagrass growth cycles can provide better clues than generalized seasonal advice.

Shallow coastal waters with productive seagrass meadows are essential feeding habitat. Sheltered bays, channels and island margins may be used, but animals also travel between feeding areas. Water clarity, tides, disturbance and seagrass condition strongly affect whether shore observation is feasible. Dugongs prefer water depths between 1 and 5 meters, which supports optimal seagrass growth and allows them to surface for air. Their preference for these shallow areas makes them vulnerable to habitat degradation and human activities. They may also utilize deeper channels for movement between feeding grounds or for protection during adverse weather.

Seagrasses form the overwhelming majority of the diet, including leaves, roots and rhizomes. Dugongs often favour nutritious, relatively low-fibre species. Small invertebrates may be consumed incidentally or occasionally deliberately, but healthy seagrass ecosystems remain central to their survival. Their specialized diet as marine herbivores means dugongs play a vital role in seagrass ecosystem health, helping to cycle nutrients. They can consume up to 40 kg of seagrass daily to support their large body size. Different seagrass species offer varying nutritional value, influencing feeding preferences and patch usage.

Common name

Dugong

Scientific name

Dugong dugon

Animal group

Mammals

Size

2.4–3 m long

Weight

250–450 kg

Lifespan

Not reliably established

Status

Vulnerable

Identification

Its dolphin-like fluked tail and strongly downturned muzzle distinguish it from manatees, which have rounded paddle-shaped tails. Their large, cylindrical body tapers to the distinctive fluked tail. Adults can reach lengths of up to 3 meters and weigh over 400 kg. Unlike seals or dolphins, dugongs do not leap or engage in acrobatic displays, typically maintaining a slow, deliberate movement.