The dugong is a stocky slow-moving marine mammal that can be found living in and around warm coastal waters between the east coast of Africa and the Pacific ocean. These marine mammals are known for their unique appearance and herbivorous nature.
While they are considered an endangered and protected species in some countries, they may still come under attack by poachers looking to use or sell their meat and bones for a profit.
Physical Characteristics and Appearance
The dugong is a large, stocky marine mammal with a rotund body that is thickest in the middle and tapers down towards the ends. Unlike the manatee, the dugong’s flippers and tail are similar in shape to many of the dolphin species as they also taper down at the ends.
The snout is a bit larger than the manatee and has a sharply angled premaxilla with a large upper lip used to help it capture food. The dugong’s eyes are small and spaced far apart, perhaps for better observation of their environment. However, the strength of their eyesight may be limited by their small eyes. Although the ears are not visible, these marine mammals are known for their acute sense of hearing.
When it comes to size, dugong can reach lengths of 8 – 10 ft. long and weigh between 550 – 1,000 lbs when fully grown, however in rare circumstances, they have been known to grow to heavyweights and longer sizes, with the largest known dugong measuring in at over 13 ft. long and weighing more than 2,200 lbs.
On average, the female dugong is generally larger than their male counterparts. In both the males and females, the bones of these marine mammals are surprisingly heavy and considered one of the densest among the animal kingdom. In addition to their meat and oil, the heavy, dense bones they possess have been known to make them targets for poachers and hunters interested in selling or using their body parts for food or tools.
Diet and Hunting Methods
The dugong is a large herbivorous animal that primarily consumes various forms of plant life, including seagrass, aquatic plants, and their roots; however, they may also consume various invertebrates in some situations species such as jellyfish and shellfish. While some dugong may consume invertebrates, their diet depends on where they live, as dugong in tropical waters does not appear to consume invertebrates.
Due to their dietary needs, dugong often searches for high-quality plants packed with nutrients and may overlook or ignore lesser quality food sources. In some cases, these marine mammals may dig up a whole plant (including the roots) or even a group of plants and shake them clean to remove any undesirable debris like sand before consuming the food.
To assist with capturing their food, dugongs use their excellent sense of smell to locate their food source and may stretch their large flexible lip out to help them dig for food and/or remove plants they have found.
Habitat and Migration
Dugong can be found traveling in warm, shallow coastal waters between the east coast of Africa and the Pacific ocean. Although these marine mammals appear to be declining in population size, they are most abundant in Northern Australia and the Arabian Gulf.
Populations appear to be extremely low or non-existent in Hong Kong and Taiwan. Other areas show signs of partial population declines, such as Cambodia, China, Japan, The Philippians, and Vietnam. Water pollution, construction, habitat degradation, commercial vehicle (boat) travel, and poaching (hunting) may contribute to declining populations.
Migration patterns for these marine mammals appear to be limited. However, some populations may travel further offshore during colder months to maintain a warm habitat year-round. Long trips may also occur when searching for food. However, most dugongs are known to inhibit a specific area and range throughout their entire life.
Groups of dugong have also been observed migrating to different areas within their area/range as available populations of seagrass and other foods tend to shift throughout their environment. To find their way back to shore after a long trip or food, hunt dugong has been observed following the tide back towards land.
Social Structure and Communication
When it comes to their behavior dugong, appear to be fairly shy towards humans and generally travel alone or in small pairs; however, there are known cases of large gatherings occurring where hundreds of dugongs may be seen together socializing. Large gatherings are typically rare, and small groups are believed to be partially caused due to difficulty finding large abundances of food in a particular area, leading to large group numbers.
The most common groups found among these marine mammals are a mother and her child or a male courting a female dugong. Communication involves using various sounds such as barking, chirping, and whistling and may also include visual cues and touching to express their intentions or interests to other dugongs. Due to poor eyesight, however, visual cues are likely to be fairly limited.
Mating, Reproduction and Lifespan
The average gestation period for dugong appears to be between 13 – 15 months. After birth, the female dugong will nurse her child for up to 18 months. However, the young dugong will usually stay with its mother until it reaches sexual maturity.
Sexual maturity may begin as early as 8 years of age; however, it may take until the age of 18 before sexual maturity occurs, depending on the dugong. The age at which females give birth is not well understood, and researchers have placed estimates between 10 – 17 years.
The reproductive frequency appears to be longer than that of the manatee, with females giving birth less frequently, once every 2 1/2 – 7 years, based on research. When it comes to lifespan, healthy dugong may live until the age of 70, with a few animals living beyond the 70-year lifespan.
Threats, Predators and Conservation
Given their coastal lifestyle, these marine mammals are fairly safe from predator attacks; however, they may occasionally be hunted by crocodiles, killer whales, and sharks in certain areas. Young and inexperienced dugong are most likely to be hunted as they present the easiest opportunities for their predators. Dugong may also be at risk of being harmed by parasites or diseases in their area.
Habitat degradation, poaching, and fishing hazards are also known threats. Habitat degradation may be caused by human involvement such as construction, boating, pollution, or natural factors that affect their food supply. While these marine mammals are a protected species, they may occasionally be hunted by poachers for their meat or bones.
Lastly, fishing hazards such as fishing hooks and other types of equipment may contribute to the deaths of these marine mammals as injuries or devices that prevent them from the surface can have a detrimental effect on their survivalist.
Note: Although dugongs are considered a protected species, they may still be hunted in countries that do not prohibit the hunting of these marine mammals.