What's the Difference Between a Dugong and a Manatee?

As I've chronicled in the archives of this very website, I am obsessed with manatees. I have loved them, adopted them, and convinced everyone I know that I need at least three tea infusers created in their likeness. But at some point in my adult life, I became aware that my beloved regal, wrinkly-faced creatures are not the only adorable plant eaters of the sea. It turns out, my cherished manatee has a similarly glorious cousin in the flat muzzled dugong.

"Dugongs are the closest living relatives to manatees," Gillian Spolarich, international communications manager at Oceana, an organization dedicated to protecting and restoring the oceans, writes via email. "Both are herbivorous, primarily grazing on sea grasses and spending most of their time in seagrass beds."

The Australian Museum describes them as having a "large, grey brown bulbous animal with a flattened fluked tail, like that of a whale," dugongs have paddle-like flippers, no dorsal fin, and a broad, flat muzzle and mouth that are angled down to help them easily eat their favorite grassy foods. They have small eyes and ears because, like manatees, they don't rely on their senses much for survival — they just go about their business, looking for plant-based treats.

Manatees Live in Fresh Water, Dugongs in Salt Water

While dugongs like to chomp on underwater plants like their manatee family members, they're distinct in one specific way: They never enter fresh water. That means they're the only exclusively marine mammal that is herbivorous. And one detail from the Oceana website that simultaneously breaks and warms my heart: "... as in most herbivores, the dugong's brain is very small compared to its body size, likely because it does not have to develop complex hunting strategies to capture prey."

Other Differences Between Dugongs and Manatees

"Dugongs are often mistaken for manatees, but they do have their differences," Spolarich says. "Manatees have round, paddle-like tails, while dugongs have fluke tails like whales. Manatees can grow longer and heavier than dugongs. They are referred to as sea cows because they use their strong, cleft upper lips to graze on sea grasses they uproot from the sea floor. In addition to living up to 70 years, dugongs can grow up to 13 feet (4 meters) and weigh as much as 595 pounds (270 kilograms)."

Where Do Dugongs Live?

According to Spolarich, while manatees live on the western coasts of the Atlantic, dugongs are located throughout the warm latitudes of the Indian and western Pacific oceans. Like manatees, female dugongs in season attract the attention of several males and eventually mate with one or two. One calf is born after a gestation period of 12-14 months (a long gestation period!) and will continue to nurse for up to a year and a half. Babies stick close to their moms for several years, and females only reproduce once every two and a half to seven years. While adult dugongs don't have any natural predators, the young ones are at risk of being eaten by animals like saltwater crocodiles, killer whales and large, coastal sharks.

They may not have natural predators, but dugongs do have one major threat to contend with: humans. "Dugongs are protected by the Endangered Species Act (ESA) and are considered vulnerable by the International Union for Conservation of Nature's (IUCN)'s Red List," Spolarich says. "They are still threatened in some places by habitat destruction, collision with boats, and accidental capture in fisheries targeting other species (called bycatch). At Oceana, we campaign for science-based policies that will restore ocean abundance and protect these important habitats. In the United States, the ESA faces attacks in Congress. Those who want to speak up on behalf of dugongs, and other ocean animals, can ask their Members of Congress to oppose any legislation that would weaken the landmark law."