The term “sea donkey” is an informal nickname, not a scientific or formally recognized animal name. This affectionate moniker is part of common parlance, used informally rather than in biological texts or official classifications. It refers to a large, gentle aquatic mammal, often sparking curiosity about its true identity.
The True Identity of the “Sea Donkey”
The informal name “sea donkey” is most commonly used to refer to manatees and, less frequently, dugongs. These are large, herbivorous marine mammals belonging to the order Sirenia, often collectively called “sea cows” due to their grazing habits. Manatees and dugongs are unique as the only living aquatic mammals that are primarily herbivorous, feeding on various aquatic plants in warm coastal waters. Although “sea donkey” primarily points to these sirenians, the term has also been used colloquially by fishermen to describe certain strong, stubborn fish, such as hake or spadefish, or even Steller’s sea lion.
Characteristics Behind the Nickname
Manatees and dugongs likely earned the “sea donkey” nickname due to several observable traits that draw parallels to their terrestrial counterparts. Their movement is typically slow and deliberate as they graze on submerged vegetation. This unhurried pace, combined with their herbivorous diet, is reminiscent of a donkey grazing in a field. Their gentle and docile nature further reinforces this comparison, as they are not known for aggressive behaviors. Physical aspects, such as their large, somewhat bulky bodies and relatively broad, flat snouts, also contribute to this perception.
Understanding Manatees and Dugongs
Manatees and dugongs are distinct species within the sirenian order, adapted to life in aquatic environments. Manatees typically inhabit shallow, marshy coastal areas, rivers, and estuaries in the Caribbean Sea, the Gulf of Mexico, the Amazon basin, and West Africa, tolerating both fresh and saltwater. Dugongs, conversely, are exclusively marine mammals found in warm tropical and subtropical waters from East Africa to Australia. Both groups primarily consume seagrass and other aquatic vegetation.
Manatees can grow up to 13 feet long and weigh between 880 and 3,900 pounds, with a lifespan of 50 to 60 years in the wild. Dugongs are slightly smaller, reaching 8 to 10 feet and 510 to 1,100 pounds, and can live up to 70 years. A key physical distinction lies in their tails: manatees have a paddle-shaped tail, while dugongs possess a fluked tail. Dugongs also have a unique, downturned snout for rooting out seagrass from the seafloor, whereas manatees have a divided upper lip for feeding on plants at various depths.
All manatee species are listed as vulnerable to extinction, while dugongs are classified as vulnerable on the IUCN Red List. They face threats primarily from human activities, including habitat loss, entanglement in fishing gear, and collisions with boats. Conservation efforts focus on protecting their seagrass habitats and mitigating human-related dangers to ensure the survival of these unique marine herbivores.