Northern Mariana Islands Territorial Mammal
Dugong (common name)
Dugong dugon(scientific name)
Dugongs are large sea mammals and are among only four living species in the order Sirenia as well as being the only surviving members of the scientific family Dugongidae. They are the world’s only herbivorous marine animals. Though dugongs live in the ocean, they also need a supply of fresh water, making them particularly vulnerable to habitat damage. Nevertheless, their range includes about 87,000 miles (140,000 km) of coastline and perhaps 48 countries. In the past, they lived in all tropical areas of the South Pacific and Indian Oceans. Though they are still fairly common in Guam, their worldwide range is now much smaller.
ALSO KNOWN AS
Sea cow, sea pig, sea camel
Dugongs are large, solid-looking animals with short front flippers that look like paddles. They look somewhat like whales, though the animals evolved independently. Though young dugongs use their flippers for swimming, mature animals rely on their fluked tails to propel them through the water and use their flippers only to steer. Dugongs have no rear fins. They are born with yellow-white skin, but this darkens to gray-brown as the animals mature.
Skin is smooth but thick with a few short, stiff hairs scattered over the body. These hairs may help dugongs sense what’s around them. They have large, rounded, downturned, bristly snouts and an upper lip that overhangs the rest of the mouth. Every dugong has tusks, but these remain under the skin except on mature males. Females are sometimes slightly larger than males, but otherwise males and females look much the same. Dugongs have strong eyesight and hearing but are not quick swimmers. The move at an average speed of 6 mph (10 kph) and often much more slowly.
70 years or longer
Coastal habitats, especially broad, shallow, sheltered areas including mangrove channels, bays, and the sheltered sides of bigger inshore islands
Range: Coastal and island waters from East Africa to Vanuatu, and from about 27° north to 27° south of the Equator.
Conservation Status: Vulnerable (VU). The dugong populations are reduced worldwide, and many small populations are cut off from larger groups and becoming extinct. The International Union for Conservation of Nature (IUCN) categorizes the dugong as vulnerable, and the Convention on International Trade in Endangered Species has imposed limits and bans on trade of dugong products, depending on the specific group of dugong involved.
Historically, people hunted dugongs for meat, oil, and for cultural reasons, and in spite of legal protection in many areas, humans continue to be the main threat to Dugongs. Hunting, reduced habitat, and accidental fishing-related deaths are the main problems. Natural predators such as killer whales, sharks, and crocodiles are also a threat, as are storms and parasites.
Calves may be born every three to seven years, depending on the population and conditions, and there is no sharply defined breeding or birthing season. It’s also not clear how long female dugongs stay in their estrus cycle. Most Dugongs, male and female, reach maturity and begin breeding when they are nine or 10 years old though as late as 15 years is possible. It’s not clear how long females continue to breed, but there’s been at least one case of a pregnant 42-year-old dugong. When mating, several males often pursue a single female, and they seem to mate with multiple partners. Females give birth to a single dugong about a year later and nurse their young for about one and a half years.
Top speed recorded: 12.5 mph (20 kph)
Breeding interval: 3–7 years
Birthing period: Year-round
Average litter size: 1 calf
Size at birth: 55–75 lbs (25–35 kg)
Click to enlarge an image
Data Source: U.S. Fish and Wildlife Service
Author: World Trade Press