Mammals
What large, gentle animal spends its days grazing underwater meadows like a cow in a field? The dugong! These peaceful marine mammals are sometimes called "sea cows" because they munch on seagrass all day long. Dugongs live in warm, tropical waters from East Africa to Australia. They look similar to manatees but have a whale-like tail instead of a paddle-shaped one. Dugongs are shy, slow-moving animals that have amazed people for thousands of years. Some people think ancient sailors mistook dugongs for mermaids! Let's learn about these wonderful ocean grazers!
Dugongs have large, round, torpedo-shaped bodies covered in smooth gray skin! Adults are usually 8 to 10 feet long and weigh 500 to 900 pounds. Some big dugongs weigh over 1,100 pounds. Their skin is thick and tough, often with scars from encounters with rocks or other dugongs. Young dugongs are lighter in color, becoming darker gray as they age!
The easiest way to tell a dugong from a manatee is the tail! Dugongs have fluked tails shaped like a whale's tail. Manatees have flat, rounded paddle tails. Dugongs also have a more pointed, downward-facing snout than manatees. Their upper lip is large and flexible, designed for grabbing seagrass from the ocean floor. Male dugongs grow short tusks that poke out from their upper jaw!
Dugongs have small eyes and tiny ear holes on the sides of their heads! They don't have external ears at all. Their flippers are short and rounded without fingernails (unlike manatees, which have nails). Dugongs are generally sleeker and more streamlined than their manatee cousins. Their whole body is suited for cruising through warm, shallow coastal waters!
Dugongs live in warm tropical and subtropical waters! They're found along coastlines from East Africa across the Indian Ocean to Southeast Asia and Australia. The largest population of dugongs lives in Australian waters, especially around the Great Barrier Reef. Dugongs also live around the Philippines, Indonesia, the Persian Gulf, and the Red Sea!
Dugongs need seagrass meadows to survive! They stay in shallow coastal waters where seagrass grows on the ocean floor. Most dugongs live in water less than 30 feet deep. They prefer calm, sheltered bays, mangrove channels, and protected coastlines. Dugongs sometimes travel between seagrass beds, but they don't migrate long distances like whales!
Australia is the most important country for dugong conservation! The waters around northern Australia and the Great Barrier Reef hold the world's largest dugong population. An estimated 80,000 or more dugongs live in Australian waters. In other parts of their range, dugong numbers have dropped sharply. Many countries are working to protect the seagrass habitats dugongs depend on!
Dugongs eat almost nothing but seagrass! They're the only marine mammals that are strictly herbivores. Dugongs graze on underwater seagrass meadows just like cows graze on land. They use their flexible upper lips to root up entire seagrass plants, including the roots. A dugong can eat 60 to 90 pounds of seagrass every day!
Dugongs feed mainly at night or when tides are high! When the tide covers the seagrass beds, dugongs move in to eat. They leave behind feeding trails-visible paths through the seagrass where they've been munching. These trails can be seen from boats and aircraft. Scientists use these feeding trails to track dugong movements and estimate population sizes!
Dugong grazing actually helps seagrass meadows stay healthy! When dugongs eat seagrass, it encourages new growth-much like mowing a lawn. Healthy seagrass beds provide habitat for fish, shrimp, and many other ocean animals. Without dugongs, seagrass beds can become overgrown and unhealthy. Dugongs are the gardeners of the tropical ocean floor!
Mother dugongs give birth to one calf at a time, usually every 3 to 7 years! The pregnancy lasts about 13 to 15 months. Calves are born underwater and the mother helps push the baby to the surface for its first breath. Newborn dugongs are about 4 feet long and weigh around 65 pounds. They can swim right away!
Baby dugongs stay very close to their mothers! Calves often ride on their mother's back or swim just above her, holding on to a flipper. Mother dugongs are very protective and will position themselves between their calf and any danger. The bond between mother and baby is very strong!
Dugong calves nurse their mother's milk for up to 18 months! They start nibbling on seagrass at a young age while still nursing. Baby dugongs learn which seagrass beds to visit by following their mothers. This knowledge of feeding areas is passed from mother to calf across generations. Young dugongs stay near their mothers for about 2 years!
Young dugongs face threats from sharks and large crocodiles! Their best defense is staying close to their mother and in shallow water. As they grow, dugongs become too large for most predators. Dugongs grow slowly and don't reach full size until they're about 15 to 17 years old. Their slow growth and reproduction make every surviving calf important for the population!
Dugongs are the only strictly marine herbivorous mammal in the world! While manatees can live in fresh water too, dugongs live only in the ocean. This makes them unique among all marine mammals. They fill a special role in tropical ocean ecosystems that no other animal can replace!
Dugongs are incredibly important for ocean health! Their grazing keeps seagrass meadows healthy and productive. Healthy seagrass beds absorb carbon, protect coastlines from erosion, and provide nursery habitat for commercially important fish species. When dugong populations decline, seagrass health often declines too!
Dugongs face serious threats around the world! Boat strikes, fishing net entanglement, habitat loss, and water pollution all endanger dugongs. Seagrass die-offs from coastal development and poor water quality reduce their food supply. In many countries, dugong numbers have dropped to dangerously low levels. Only Australia still has a large, healthy population!
Protecting dugongs means protecting entire ocean ecosystems! When we save seagrass meadows for dugongs, we also help fish, sea turtles, seahorses, and countless other species. Dugongs are an "umbrella species"-protecting them protects everything that shares their habitat. These gentle sea cows deserve our help to keep swimming through the warm oceans of the world!