Dugongs are fascinating marine mammals that are often confused with manatees. These gentle giants are also the start of the mermaid myth. Here are 7 interesting facts about dugongs, shedding light on their unique life and behavior.
Phylum: Chordata
Class: Mammalia
Order: Sirenia
Family: Dugongidae
Genus: Dugong
1. The dugong resembles a cow
The dugong is a marine mammal in the order Sirenia which also includes 3 manatees species. Because of their robust and massive appearance, these species are commonly referred to as “sea cows”. They possess a bulbous body with greyish-brown skin. Their skin is coated in fine hairs, especially around their mouth, to enhance their tactile abilities.
Sea cows have small eyes and ears, wide mouth and large flat nose that are inclined down, short paddle-like front flipper fins, and no dorsal fin. They don’t have a paddle-shaped tail like other members of the Sirenia order. These species own a flattened fluked tail resembling that of a whale. This characteristic is the difference between dugongs and manatees.
The animals have a size ranging from 2.4 meters up to 4 meters in length and weigh between 300 to 500 kilograms.
2. They closely related to elephants
Despite being commonly referred to as ‘sea cows’, dugongs are actually related to elephants and shared the same ancestor about 50 – 60 million years ago. Scientists believe that while elephants evolved to live on land, dugongs adapted to life in the sea.
Protein examinations of their eye lenses also indicate that they are related to hyraxes and elephants. Similar to elephants, these sea cows can grow tusks, which can help estimate their age based on the number of prominent rings on those tusks.
In addition to physical similarities, these sea mammals also share social traits with elephants. They both have common language and strong sense of community.
The dugong animal is one of Pokemon based on animals in real life – Dewgong, you may find more related articles below:
- Quilladin – Procupine
- Heliolisk – Frilled Lizard
- Hippopotas – Hippo
- Psyduck – platypus
- Shellos – Loch’s chromodoris
3. Natural Habitat
Dugongs, unlike manatees, only live in aquatic environments, with a preference for tropical coastal regions. Their range covers waters in 48 countries, extending from the Egyptian Red Sea East Africa, and the Arabian Gulf to the Indo-Pacific region, reaching as far as Australia.
In Australia, they can be found from Moreton Bay in southern Queensland across northern Australia to Shark Bay in Western Australia. In addition to Australia, these sea cows also live near Thailand, India, and Madagascar, as well as in various oceans around the United States.
They like broad, shallow bays protected by big inshore islands. However, their proximity to the shore puts them at risk from bigger boats and other coastal activities.
4. They’re social mammals
Dugongs tend to be gregarious creatures that are typically observed in pairs, usually consisting of a mother and her baby. They can also gather in big groups, ranging from 6 to 200 members. However, these big herds don’t tend to stick around for extended periods of time due to the limited availability of seagrass.
These cute creatures are semi-nomadic. This means some of them will migrate great distances while others remain in a particular area for their entire lives. Their movements are solely dictated by food availability.
While being aquatic animals, these species may occasionally venture onto land, particularly in regions with brackish water – a combination of saltwater and freshwater.
Typically, sea cows are quite timid and tend to move away if disturbed. You can only watch them from a distance. These creatures are not dangerous and pose no threat to humans. For that reason, you can also swim with them.
Their eyes are small and the species live in well-lit shallow waters. Therefore, they don’t rely heavily on their eyes. Instead, they use their keen sense of smell to find food and detect danger. To communicate with other dugongs, they use a variety of sounds that travel through the water, including barks, trills, blows, chirps, squeaks, and whistles.
Due to their big body mass, the sea animals move slowly at a speed of 10 kph. They can dive to depths of 37 meters to consume seagrass and can stay there for up to 11 minutes without breathing. Like whales, these marine mammals need to take oxygen through their lungs. To do this, rise to the surface and support their heads above water by standing on their tails.
5. They’re the only herbivorous sea mammals
Dugongs are the world’s only herbivorous sea mammals. As primary consumers, they rely solely on seagrass as their primary food source, this is another reason why they get the nickname “sea cows.” If their main food is sparse, they will also consume algae and other marine plants.
Due to their diet, these species don’t need to have predatory instincts or tactics. Therefore, they have a relatively small brain, weighing only about 300 grams in comparison to their large body.
Instead of eating merely the leaves, these sea cows use their top lips to remove the whole seagrass plant, which results in dugong “trails.” They feed for up to 24 hours a day and can consume up to 88 pounds of seaweed each day. Before eating the seagrass, they shake their heads to remove sand from the food.
Though their food supply is beneath the waves, sea cows cannot stay submerged for a long time as mentioned above. This is why they prefer shallower, temperate water with plenty of seagrasses.
The animals are preyed on by many predators like crocodiles, sharks, and killer whales.
6. The mother and her calf have a strong bond
Dugongs do not have a specific mating season, they mate all year round. The females become sexually mature at the age of six and give birth to only one calf every 2.5-7 years.
Male gather together in a mating train and follow a single female in the hope of getting a chance to mate with her. Alternatively, in some areas, males congregate in one location to impress the females. Either way, they will end up fighting with each other to breed with females.
They mate polygynously, with a female mating with several males. This ensures a higher chance of successful conception.
The gestation period of the female lasts about 12-14 months, after which a single calf is born. The mothers dedicate most of their time to nursing and caring for their calves for 18 months or longer. During this time, they rarely venture far from their mothers’ side. People often see them clinging to her back.
The long weaning period and low reproductive rate contribute to the decline in the dugong population. The young are vulnerable to predators such as sharks and crocodiles, which further decreases their numbers.
Sea cow offspring keep staying close to their mother until they are between 6 and 9 years old. This is why pairs of dugongs are often mothers and calves. When reaching this age, the young venture out to find a mate of their own. Their lifespan in the wild can be over 70 years.
7. Conservation Status
Sea cows have a significant impact on the preservation of coastal ecosystems. By continuously grazing on seagrass, they promote regrowth and provide essential habitats and feeding grounds for various marine creatures such as fish, turtles, etc.
Unfortunately, dugongs are listed in the Convention on International Trade in Endangered Species. They are also classified as vulnerable and endangered species on the IUCN Red List and the US Federal List respectively. It’s estimated that there are about 30000 dugongs left in the world. The biggest numbers are in Australian waters.
Human activities are mostly to blame for their endangered status. Dugongs often become entangled in fishing nets and are unable to reach the surface for air. Due to their feeding habits in shallow waters, they are prone to injuries from boats, even dead.
Such stresses can also reduce the reproductive rates of females. Given their slow reproductive rates (average 5% per year), dugongs suffer significant population losses with every death.
Habitat degradation from changes in water quality and coastal development further exacerbates the decline by reducing their food sources and habitats. They are also hunted illegally for consumption and trade, which further diminishes their numbers.
References:
