General facts About Manatees.
The Manatee, also known as the Sea Cow, earned its name from the similarity to cows on land. These Herbivorous mammals graze slowly on seagrass and tropical water plants. Our friends are peaceful and slow-moving. They are not harmful to humans, and instead will often approach them out of curiosity. Within their family, there are 3 subspecies of Manatees: The Amazonian Manatee, The West Indian Manatee, and the West African Manatee.
The name “Manatee” is derived from the Latin word “Manus” or “hand”. This is because of their paddle-like flippers, which have a human-like skeleton. Their specific name inunguis also means “Nailless”, further influenced by its near-human hand structure. However, some species of Manatees do have fingernails, which do not serve them currently, but perhaps served them in the past.
The Amazonian Manatee is the smallest of the three subspecies. They belong to the family Sirenia, of which they are the only member to live in freshwater. Sirenians are also distantly related to Elephants. Manatees evolved from elephants 500 million years ago. This group of land mammals was a much more diverse group than the modern-day, which included Mammoths and Hyraxes.
The Amazonian Manatee: Out of the Blue!
What is the size, weight & colour of the Manatee?
Because these Manatees are freshwater bound, they are much smaller than their saltwater cousins. The Maximum weight observed in the Amazonian Manatee is 379kgs. Like many aquatic mammals, the females grow slightly larger, with an average of 379kgs in weight, and 2.6m in length. Males grow to be an average of 346kgs, and 2.5m in length.
Our friends are experts in blending in! The Amazonian Manatee has grey skin which helps conceal itself in stirred-up rivers. In addition to its natural hue, algae will sometimes change their colour to a greenish-brown. The only bright shades you will find on this Manatee are on the underbelly, which has pink and white patches.
What type of vision does the Manatee have, and what sounds do they make?
The Amazonian Manatee relies on its whiskers to help them navigate murky waters. Due to their sixth sense, their vision is underdeveloped. Studies have found that Manatees can see blue and green light, but they cannot process red. Their eyes share characteristics with humans where they have rod cells, which help them see in low light.
Manatees emit low chirps and squeaks to communicate with each other. These noises are used to express excitement and fear – as well as mating calls. It is also possible that Manatees also use infrasound, which is a low-frequency tone that humans cannot hear.
Are there any special or unique physical attributes?
Our friends are related to Elephants and are quite heavy as a result! Because of their weight, The Amazonian Manatee relies on its buoyancy to remain afloat. This is achieved by storing gas in its system – or “holding it in”. The vegetation they consume generates a lot of gas that must be released by means of flatulence. Manatees as a species “pass gas” as a side effect of their buoyancy – while releasing it to propel themselves! Many excited tourists have documented this comedic spectacle.
In addition to this, a sleeping Manatee is another comedic sight. Our friends must breathe and sleep at the same time, and therefore will float along the surface of riverbeds belly-up. This allows them to sleep and breathe without gills. Most Manatees are day-sleepers and can be found drifting unconsciously through the Amazon River at mid-day.
How fast is the Manatee?
The Amazonian Manatee swims at speeds ranging from 8km per hour to 24km per hour. The higher speeds come in short bursts, as these slow movers spend a lot of their time eating and resting. They can spend hours grazing along the same riverbed but are always on the move for more food.
What are their Migration Routes?
The Amazon River spans Northern South America, where this Manatees is found. It is unlikely that they reach the Orinoco River and Amazon basins. Instead, they are found close to the main arteries. This spans across 6,575km of riverbeds.
How do they hunt, and what do they eat?
Manatees use their hand-like flippers to dig and collect plants along riverbeds. Their favourite meals include grasses, water hyacinths, water lettuce, and floating palm fruits from neighbouring trees. Our friends eat an average of 10-15% of their body weight daily, which can reach 80kg of vegetation. Naturally, this means the Amazonian Manatee spends its entire life sleeping and eating.
What are their natural enemies?
Predators for the Amazonian Manatee extend beyond the river, with Jaguars topping the list. Crocodiles and Sharks also prey on this slow mover. However, they rarely fall prey to these predators because their thick hide is difficult to penetrate and digest. The greatest threat to the Amazonian Manatee is Human activity.
Where do they live?
Our friends can be found from the mouth of the Amazon River to tributaries in Brazil, Ecuador, Colombia, Guyana, and Peru. These Manatees spend their entire lives in the Amazon River. Since Manatees are mammals without gills, they cannot breathe underwater. The maximum amount of time a Manatee can hold its breath is 20 minutes, but you will see them rise to the surface every few minutes on average. They are entirely aquatic mammals and never leave the water.
All about Reproduction.
Manatees reproduce every 2-5 years, with a gestation period of 12 months. After birthing, the calf stays close to its mother carried on her back or side for up to 2 years. The calves nurse on their mother for the first year in combination with seagrass, while during the second year they slowly grow large enough to become independent.
Manatees have a lifespan ranging from 12.5 to 32 years. It takes 5-10 years for an Amazonian Manatee to reach sexual maturation. Consequently, some Manatees may only produce one calf in their lifetime. This breeding time is observed throughout the full year. With most occurring seasonally in January or June.
Manatees inspired the original myths of Mermaids. In his first journey to America, Christopher Columbus spotted 3 “maid-like” figures from his boat. Manatees can stand up on their tale in shallow water, making it possible to mistake them for humans from afar. Skeletons of Dugongs and Manatees were often mistaken for potential Mermaid discoveries due to them sharing human-like qualities. This mistake is still common today, with many tourists finding washed up skeletons on shores with arms, hands, and fins.
What threats do the Manatees face?
Soil erosion and deforestation have caused riverbeds to produce a weaker supply of food for our friends. This is the single greatest threat for Manatees considering how much they need to consume every day to survive. Conservation laws have been placed to protect areas of the Amazon. However, a large portion of it remains unprotected to this day.
Endangered Ranking – IUCN.
According to the IUCN, the Amazonian Manatee is an Endangered species. This is due to commercial hunting for its meat, oil, fat, and hide. Hunting these creatures has been illegal since 1973, but this does not stop them from being caught in commercial fishing nets as bycatch. Illegal hunting still occurs, with 460 Manatees killed in protected areas in the last decade.
Why is this Manatee endangered?
Commercial fishing for the Amazonian Manatee occurred between 1542 and 1973. Hundreds of years of hunting these mammals have caused a severe drop in their populations. While they are currently protected – restoration of their numbers is unlikely. They reproduce every 2 years and take up to 10 years to reach sexual maturity.
Why should you care?
Amazonian Manatees have a profound impact on the health of the river itself. Upon digesting and processing aquatic plants, they provide necessary fertilizer to produce more vegetation. Their feeding of these plants also prevents the obstruction of riverbeds due to overgrowth. Without the Manatee to act as a natural lawnmower, the riverbeds would become overgrown and flood neighbouring forests. The Amazon Rainforest pulls a significant amount of carbon dioxide from the atmosphere, acting as the earth’s air conditioner. Our friends play a vital role in the health of the Amazon River and the Amazon Rainforest, and without their help, we would see negative impacts on our own air quality.
What can you do to help?
- Ethical Consumption: Manatees meat and blubber are still sold as bycatch in fishing markets. These mammals are slow swimmers and often become entangled in commercial fishing nets. Refuse to endorse the trade of Manatee meat and refuse to consume it.
- Spread the word! Talk to family members and friends about what they’re doing to help the cause. Inform people on ways they can help protect the Manatee and its habitat. Many organizations collect funds for research on Manatee conservation and the Amazon Forests surrounding them.
- Get Involved: Lastly, spend time signing petitions and getting involved in online spaces. Bringing attention to the deforestation of the Amazon Rainforest will in turn help its inhabitants.
If there is a public demand for change, then change will come. With everyone’s help, we can create new standards for the ocean and all of its inhabitants! With safer oceans, we will continue to see Manatee populations stabilize.