I have always had trouble with speeling, but some words give me more trouble than others. Today’s animal, the dugong, is one of those. You see, long before I knew that dugongs were an actual animal, the Pokémon games taught me about dewgong the ice/water type Pokémon. So I’ve always tried to spell dugong ‘dewgong’, and been surprised when spell check corrects it. You have no idea how many words I can’t spell because of Pokémon. It’s a serious problem.
Dugongs are part of the order Sirenia, which only has four species – the dugong and three species of manatee. The dugong is the only one of the sirenians that lives fully in a marine environment, and is actually the only herbivorous marine mammal. Their range is broad but broken up; they live in tropical waters from East Africa to Oceania. Dugongs prefer to stay in shallow, coastal waters where their main source of food grows.
Like all sirenians, dugongs are big and bulky. They are a little slimmer than manatees and have a concave-shaped tail that differentiates them from manatees. They can grow to 2-4m in length, weighing between 230 and 430kg. They are brown-grey, with skin that changes colour depending on which types of algae grow on it. Dugongs have large snouts that have large muscular lips hanging over it. It’s this lip that makes dugongs look so ridiculous, but it also helps them forage for their food.
Dugongs occupy a generally unused niche in the marine ecosystem – they eat sea grass. They use their thick muscular snout to push away sand and get to the roots of the sea grass, which contain more nutrients than the leaves of the plant. To digest the seagrass, dugongs have super long intestines – over 45 metres. They also have an enlarged cecum that contains bacteria that helps digest their plant-heavy diet.
Dugongs grow slowly and are long-lived – they can live over 70 years in the wild. They become sexually mature between 6 and 17 years of age. When males hit puberty, two tusks erupt from their snout. These incisors grow throughout the dugong’s life (in both males and females), so you can tell the age of a dugong by looking at the rings of growth on its tusks. Males advertise to females by forming leks and competing for the attention of females.
Gestation lasts 13 months and calves are big when their born: they weigh 30kg and are already over a metre long. The calves stick with their mothers for a long, long time. The calf stays very close to its mom, sometimes riding on her back to help with swimming. It nurses for over a year and a half, even though a baby dugong starts eating seagrass almost as soon as it’s born. I guess if you get nutrients from two different sources you can grow a lot faster. The calf doesn’t leave its mom when it’s done suckling though – it only sets out on its own at about six years of age at the earliest.
Dugongs are giant, silly looking creatures, so I’ve always found it a bit odd that they’ve been said to have been mistaken for mermaids by sailors. I can see dewgong being confused with a pretty fish woman, as its adorably cute. But dugongs? That’s a little weird, unless sailors in the old days liked hefty dames.
Cover image By Julien Willem (original photograph), Papa Lima Whiskey (derivative edit) – Own work, CC BY-SA 3.0