Marine mammals such as manatees and dugongs often capture the interest of those fascinated by ocean life. Though similar in appearance and behavior, these two species have distinct characteristics that set them apart. Understanding these differences not only enriches our knowledge of marine biodiversity but also highlights the unique adaptations each species has developed for survival.
Classification and Habitat
Manatees are part of the Trichechidae family and are defined by three species found in different regions throughout the world. The West Indian manatee (Trichechus manatus) can be found along the coastal waters of the Caribbean Sea and the Gulf of Mexico, particularly in Florida’s canals and springs. The Amazonian manatee (Trichechus inunguis) is found in the freshwater habitats of the Amazon Basin. And the West African manatee (Trichechus senegalensis) inhabits the rivers and coastal areas of West Africa. Manatees are more versatile in their habitat preferences as compared to the Dugong, occupying both freshwater and marine environments. They also prefer warmer waters, which is why you are more likely to find them in temperature-consistent Florida springs during winter months.
Dugongs (Dugong dugon) belong to the Dugongidae family and are found primarily in the warm coastal waters of the Indian and Pacific Oceans. They prefer shallow areas where seagrass beds are abundant, from East Africa to Australia, including the Red Sea and the coastal waters of Southeast Asia. Dugongs are the only strictly marine herbivorous mammal, relying entirely on sea grasses for sustenance.
Physical Differences
While both dugongs and manatees share a similar, robust body shape adapted for aquatic life, several physical traits distinguish them:
Tail Shape
Manatees possess a paddle-shaped, rounded tail that is broad and flat. This tail design is more suited for slow, leisurely movements in their typically calm water habitats. The manatee’s tail allows for gentle propulsion, ideal for their slow-paced lifestyle.
Dugongs have a fluked tail similar to that of a dolphin, which is distinctly notched and forked. This tail shape aids in swift and agile swimming. The fluked tail is a key feature that helps distinguish dugongs from their manatee cousins, especially when observed from above or behind in the water.
Snout and Mouth
Manatees have a flexible, prehensile upper lip that assists in gathering and manipulating food. Their snouts are less pronounced and their mouths are more forward-facing, suited for feeding on a variety of aquatic plants. This flexibility allows manatees to feed on different types of vegetation, including those found in freshwater rivers and lakes.
Dugongs have a distinctive, downward-facing snout that allows them to graze efficiently on seagrass beds. Their upper lip is split and muscular, helping them uproot seagrass. This adaptation is essential for their feeding habits, as they primarily feed on seagrass found on the ocean floor.
Skin and Size
Manatees tend to have rougher, wrinkled skin with more pronounced body hair, especially around their snouts. They can reach lengths of up to 4 meters and weigh as much as 590 kilograms. The rough texture of their skin can help them navigate through their often more turbid and variable environments.
Dugongs have smoother skin that may appear hairless but can have some sparse bristles. They typically grow to around 2.4 to 3 meters in length and weigh between 230 to 500 kilograms. Their sleek skin helps them glide through the water with ease.
Behavior and Diet
Both manatees and dugongs are herbivores, primarily feeding on seagrasses and other aquatic vegetation, but their feeding behaviors reflect their habitat differences:
Manatees inhabit both freshwater and marine environments. They have a more varied diet that includes a wide range of aquatic vegetation, such as floating and submerged plants, algae, and sometimes even small fish or invertebrates. Manatees are known for their gentle, slow-moving nature and can often be seen grazing near the water’s surface or along riverbeds. They typically consume about 10-15% of their body weight in vegetation daily, which helps maintain the health of their ecosystems by controlling plant growth.
Dugongs are exclusively marine and spend their lives in the ocean. They feed mainly on seagrass, grazing for up to eight hours a day. Their specialized snouts help them dig up entire seagrass plants, including roots. Dugongs have a unique way of feeding that involves rooting in the seagrass beds, which can leave noticeable trails or “feeding scars” in the vegetation.
Reproduction and Lifespan
Both manatees and dugongs have relatively long lifespans and low reproductive rates, which makes them vulnerable to population declines:
Manatees have a similar reproductive cycle, with a gestation period of about 12 months. Female manatees also usually give birth to a single calf, although twins can occasionally occur. Calves remain dependent on their mothers for about one to two years. Manatees can live up to 60 years or more in the wild, but like dugongs, their populations are at risk due to human impacts.
Dugongs have a gestation period of about 13-15 months, and females typically give birth to a single calf every 3 to 7 years. Calves stay with their mothers for up to 18 months, during which they learn essential survival skills, such as finding food and avoiding predators. Dugongs can live for over 70 years in the wild, although this longevity is threatened by human activities and environmental changes.
Conservation Status
Both manatees and dugongs face threats from human activities, including habitat destruction, boat collisions, and entanglement in fishing gear. Their conservation statuses highlight the need for ongoing protection efforts:
Manatees also face similar threats and are listed under varying conservation statuses depending on the species. The West Indian manatee, for example, is considered vulnerable, while the Amazonian manatee is classified as endangered. Efforts to protect manatees include enforcing boat speed regulations in manatee habitats, preserving critical habitats, and public education campaigns to raise awareness about the dangers they face.
Dugongs are classified as vulnerable by the International Union for Conservation of Nature (IUCN). Their populations are declining due to habitat loss, hunting, and incidental capture in fishing operations. Conservation efforts for dugongs include habitat protection, creating marine protected areas, and reducing bycatch through the use of more selective fishing gear.
Manatees vs. Dugongs
Though manatees and dugongs share a common ancestry and similar ecological niches, their differences in physical traits, habitats, and behaviors reflect the diverse ways in which marine mammals can adapt to their environments. Understanding these differences not only enhances our appreciation for these gentle giants but also underscores the importance of tailored conservation efforts to protect these unique species and their habitats. Through concerted global efforts, we can help ensure that both dugongs and manatees continue to thrive in their natural environments, contributing to the health and diversity of our planet’s marine ecosystems.
In this context, promoting eco-friendly and sustainable travel is crucial for their protection. Ecotourism encourages responsible practices that minimize environmental impact and support conservation efforts for these species. By embracing ecotourism, travelers can help ensure future generations can enjoy and benefit from the presence of manatees and dugongs in their natural habitats.
