In the River Safari, lives a family of magnificently mysterious creatures that float around in the water effortlessly to enchant visitors venturing into the Amazon Flooded Forest. They continue to captivate those who catch sight of them, just like how they enthralled Christopher Columbus, all those years ago on his voyage to America, to quite possibly inspire the mermaid myths that are still whispered about to this day.
They are the West Indian manatees.
In consideration of Manatee Appreciation Day coming up on 25 March 2015 (the last Wednesday of March every year), let’s pay a tribute to how special these evolutionarily distinct and globally threatened animals are.
These large, round and grey mammals belong to the order Sirenia, which only includes two other species of manatees and the dugong. They are more closely related to the elephants than other marine mammals such as whales and dolphins. The West Indian manatee can move freely between fresh and salt water, and tend to be found in areas such as shallow rivers, estuaries and creeks where fresh water is available for drinking.
For animals that can sometimes consume up to 15% of their body weight a day, you would think that the manatees would be more active! But between feedings, they spend most of their time resting – either suspended at the surface of the water or on the bottom. What a way to live!
How does such a huge animal stay afloat? One might wonder… Well, manatees, as well as dugongs produce a large amount of gas when they digest all that plant material, which makes them remarkably buoyant. Be sure to stay clear of them when you see bubbles appearing in the water beside them!
On top of their “eat and sleep” lifestyle, they have a low metabolism, which keeps them ‘well-rounded’. Despite that, manatees still have difficulty regulating their body temperatures and are therefore vulnerable to cold temperatures. As such, West Indian manatees will come together in large groups in warm water zones during cold periods to keep warm.
Usually, these animals tend to be solitary other than mothers with their calves or oestrous females with males pursuing them. Despite their solitary nature however, the manatees do occasionally initiate affiliative interactions when they meet, and are seldom aggressive, except when it comes to the males jostling for a strategic position beside a receptive female.
On that note, captive manatees are kept in obligate social conditions. What does that mean for their social dynamics?
Selected affiliative interactions were frequently displayed amongst individuals with rare occurrences of aggressive interactions. This is not to say though, that all captive groups will follow the same model. And so, it is important for all institutions housing animal collections to continuously monitor the behaviour of the animals under their care and be prepared for any potential issues.
Wildlife Reserves Singapore currently manages twelve West Indian manatees, three adults of which were donated from overseas institutions with the rest born in the Singapore Zoo, where they used to be housed, and later on in the River Safari, where they have been relocated to and are currently housed. Preliminary observations have been conducted on their group dynamics and with the increasing group size; further studies are planned for our herd of West Indian manatees.
Whilst we watch them glide gracefully around in the Amazon Flooded Forest and bask in the awe and serenity that they infuse their audience with, let’s spare a thought for their wild conspecifics . Manatees, together with dugongs have been poached extensively for their meat, hide and oil. However, presently, their greatest threats include colliding with the hulls and propellers of boats and being caught in fishing nets.
Habitat loss is another major pressure on their numbers. On top of the development of coastal areas, their habitat also suffers from blooms of toxic algae that grow rapidly during warm seasons, particularly in areas with nutrient pollution from fertiliser run-off further boosting the algae growth. These issues not only affect the manatees but all other aquatic animals too.
Manatee Appreciation Day is dedicated to raising awareness about these fascinating creatures, but even after your celebrations, do remember that you can make a difference on any day of the year. Learn more about the manatees, start an awareness campaign, or donate to manatee conservation programs. Most importantly, think about the choices you make on a daily basis and how they can potentially impact the environment and animals in it.