Manatees. You either love them or hate them. I have a pirate captain that absolutely hates them. But I think most people tend to like them.
Manatees, also known as sea cows, are aquatic mammals. When possible, they like to be alone, in a pair, or in a small group of fewer than 6 manatees. When resting, they can stay submerged for up to 15 minutes, while when swimming they can stay underwater for about 3-4 minutes at a time. Being a mammal means they need to breathe air, just like mermaids and humans. In fact, some sailors thought they were seeing mermaids when they first saw manatees!
There are 3 species of manatee: African manatees, off the west coast of Africa; Amazonian manatees, in the Amazon River; and West Indian manatees, or the North American Manatee, found mostly from Florida to Brazil. Today we’ll be talking about the West Indian Manatee, or Trichechus mantas, which can further be broken down into two subspecies - the Florida Manatee (found all the way from Texas up to Massachusetts!) and the Antillean or Caribbean Manatee (found from Mexico to Brazil). The West Indian Manatee is the largest surviving member of the Sirenia order, which also includes the dugong and the extinct Steller’s sea cow.
Manatees are large, grey blobs. Or at least that’s what they look like. From the surface, you’ll probably only see their nose and nostrils. They range from about 8-13 feet, weighing 440-1300 pounds. The females tend to be larger than the males. All over their bodies they have highly sensitive vibrissae, similar to whiskers, that help them with feeding and navigation. They’re body is fully adapted to their environment, and they don’t have any hind limbs. Instead, they use a spatula-like paddle to power them through the water; they can go up to 15 miles per hour when swimming, but tend to glide around 5 miles per hour on average. The Florida manatee has 3-4 nails per flipper. They also don’t have any external earflaps, which helps to decrease their resistance in the water, keeping their bodies more streamlined. Manatees also have 3-5cm long hairs covering their body that helps to provide sensory information. Their bones are solid and very dense, which contributes to their buoyancy negatively (meaning it would make them sink), but they have such a high level of fat content, which contributes to their buoyancy positively (meaning it would make them float), that it balances out perfectly allowing the manatees to be neutrally buoyant. This allows them to to use their breath to float or sink, just like mermaids!
One super fun fact about manatees is that they’re born underwater! Calves are born 4-5 feet in size, weighing 60-70 pounds! The mother will bring the calf to the surface for a breath, and after the first hour of life the baby manatee can swim on its own! Calves will stick with the mother, feeding on their milk, for the first two years of their lives. A new calf can be born every 2-3 years per female. When it’s time to breed, several males will form a herd around the female, fighting for her attention. Manatees do not mate for life and will go their separate ways after mating.
The closest relative to the manatee is the elephant! Much like their elephant cousins, manatees have a prehensile snout to assist them in grabbing their food and bringing it to their mouths. In their mouths, they have 6-8 molariform teeth per jaw quadrant. Each month these teeth rotate 1-2mm, which creates an unlimited tooth production. This helps the manatee as manatees spend up to 8 hours a day eating 5-10% of their body weight! They are herbivores and feed on water grasses, weeds, and algae.
Manatees can communicate vocally. Different age groups sound different and it is thought that each manatee has their own unique vocal sounds, just like each human has their own voice as well.
When water temperatures fall below 68 degrees Fahrenheit or 20 degrees Celsius, manatees can suffer from cold induced stress or mortality. They can withstand large changes in salinity, so it’s not unusual for an ocean manatee to warm up in the freshwater springs in the winter. The Florida Springs are 72 degrees Fahrenheit year-round, so in the winter, hundreds of manatees will head into the springs or nearby power plant areas to escape the cold. Algae, barnacles, and other organisms take advantage of the opportunities they would have with a manatee and several hitch a ride on a manatee’s back. In the winter when the springs are full of manatees, you can tell which came from salt water by the barnacles on their back or freshwater by the algae on their back.
There are four (4) subpopulations of Florida manatee: Northwest, Southwest, Atlantic Coast, and St. John’s River. They have been found as far west as Texas, and as far north as Massachusetts! For several years, and sometimes still occasionally, here on Delmarva we have had a manatee that likes to frequent the Chesapeake Bay. His name is Chessie! Large concentrations of manatees in Florida can be found in Crystal River and Blue Springs. Crystal River is the only place to legally swim with a manatee in the state of Florida.
If you come across a manatee, there are a few rules you must follow! Don’t touch, chase, poke, pinch, corner, or stand on a manatee! Do not disturb resting manatees. Move very slowly and reduce your splash and noise. Don’t use fins, and stay out of roped off areas (these are protected areas for the manatees to rest). Most importantly, just float at the surface! Wait for them to come to you. Manatees are curious creatures and will come up to say hi, but you must remain on the surface and do not harass the wildlife!
There are no natural predators to the manatee, but they are listed as threatened on the Endangered Species List! They are vulnerable to hunters that want their hides, oil, and bones. Motorboats and fishing nets are also major problems for the manatees. Over 20% of manatee deaths per year are due to watercraft collisions, and 96% of adult Florida manatees have scars from boat collisions. These white scars stand out on their grey bodies and last decades. Other threats to the manatee include harmful algae blooms, known as red tides, loss of warm water habitats, and entanglement, entrapment, and ingestion of debris.
Have you ever seen a manatee in the wild? Let me know in the comments below!