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Manatee Species, Facts, and Problems: Intriguing Sea Cows

Linda Crampton is a writer and former teacher with an honors degree in biology. She loves to study nature and write about living things.

A mother manatee and her calf in Palm Beach Inlet, Florida

A mother manatee and her calf in Palm Beach Inlet, Florida

Interesting Animals in Trouble

Manatees are interesting animals that are also known as sea cows. They are large and herbivorous mammals that have flippers instead of legs and a flat tail. They live in the ocean, rivers, or canals. Most of them have no problem moving from salt water to fresh water. Three species of manatees exist. Though it may sound like a strange idea, the animals are thought to be the basis of the mermaid legends.

Unfortunately, the subspecies that lives in Florida is in trouble. The animals are dying due to the loss of the seagrass that forms the major part of their diet. Pollution is believed to be responsible for the plant's death. As of mid 2021, the manatee population in Florida had experienced more deaths than had ever been recorded in an entire year in the area.

A manatee resting at Three Sisters Springs in Florida

A manatee resting at Three Sisters Springs in Florida

Manatee Classification

Manatees are mammals and therefore breathe air. Their ancestors lived on land. The animals are distantly related to elephants and hyraxes. They belong to the order Sirenia and the family Trichechidae. Dugongs belong to the same order as manatees but to a different family.

In the 1700s, another member of the order Sirenia lived on Earth. The Steller’s sea cow (Hydrodamalis gigas) was a huge animal that was over thirty feet long. It was discovered by Europeans in the eighteenth century and sadly became extinct in that century. It was killed for meat and fat. Scientists are still investigating whether additional factors were responsible for its extinction besides hunting.

Members of the order Sirenia reminded some people who lived in the past of the mythological Sirens. These beings produced beautiful songs that lured sailors to their death. Manatees do produce a variety of sounds, but they aren't musical ones. The mermaid and Siren legends show how the animals have impressed people over time.

The three living species of manatees are listed below.

  • Trichechus manatus is often known as the West Indian manatee. The species is found in Florida and nearby parts of North America, Central America, the northern part of South America, and the Caribbean.
  • Two subspecies of the West Indian manatee exist. They are commonly known as the Florida manatee (Trichechus manatus latirostris) and the Antillean manatee (Trichechus manatus manatus).
  • Unlike the other species, the Amazonian manatee (Trichechus inguinis) never enters salt water. It lives in the Amazon basin and is found in multiple countries.
  • Trichechus senegalensis, or the African manatee, lives in western Africa. It's the least known species in the genus. Its population is said to be in trouble due to human activities.

The facts below apply to the manatees seen in Florida and nearby areas. Some of the facts may also apply to other members of the genus Trichechus. The Florida animals live in coastal water, in rivers, and by springs.

Physical Features of Manatees

Florida manatees has some noteworthy physical features. They have characteristics that are related to ours but are specialized for the different lifestyle of the animals.

Weight and Size

The Florida Fish and Wildlife Conservation Commission (FWC) says that adult manatees in their area generally reach a length of up to 9 to 10 feet and a weight of up to 1,000 pounds. They also say that the animals sometimes reach a length of over 13 feet and and/or a weight of over 3,500 pounds, which is an impressive size.

Skin Features

The skin of the animals is covered by fine hairs. Bristles are located around the mouth. The skin has a leathery and flaky appearance. Manatees are grey in colour, but the algae that grow along their back make them look green or brown. The flaky skin helps to remove algae, preventing it from becoming too abundant.

A Bulbous Snout and an Unusual Lip

The North American manatee has a bulbous snout with a blunt edge at the front. Its nostrils close when the animal is under water. Its upper lip is prehensile, or able to grab objects. The lip is divided into two sections, which can each move independently from the other one.

Mouth and Marching Teeth

The mouth contains ridged pads to help break up food. The teeth help to do this job as well, but the only type that the animal possesses is the molars. When the molars wear down, they are lost and replaced by new ones from behind. The teeth are referred to as marching molars because new ones "march" into place when old ones are lost.

Flippers

The animal has a muscular body. It uses its flippers to steer its movements and to hold plants that it's eating in place. The flippers contain bones that resemble the ones in our fingers. As can be seen in the videos, the flippers are also used in leg-like actions. The West Indian and the West African manatees have structures resembling fingernails at the tip of their flippers. The Amazon manatee lacks these structures.

Tail

The animal moves its flat, paddle-shaped tail up and down to help propel its body through the water. Though the animal usually moves slowly, it's capable of moving fast for short periods. The dugong looks quite similar to a manatee, but one difference is that its tail is fluked (divided into two lobes).

The face of a manatee

The face of a manatee

Our ears consist of external, middle, and inner ears. Manatees lack external ears. Nevertheless, they are believed to have good hearing.

Respiration and Unihemispheric Sleep

Manatees are said to be completely aquatic, though they raise their head and sometimes their upper body out of the water to breathe and to inspect their surroundings. Like us, they are mammals and must breathe air. The animals sometimes stay underwater for as long as twenty minutes, though a shorter time seems to be more common. They can stay underwater far longer than us, however.

One ability that enables them to stay underwater for a long time is that they change as much as 90% of the air that they inhale. The change involves oxygen absorption from the air and carbon dioxide release into it. Humans change a much smaller quantity of the inhaled air, though the reported percentages that I've seen vary. Our respiratory tubes and sacs contain so-called dead air that isn't used for gas exchange.

Manatees sleep while submerged in water. While they are sleeping, they rise to the surface periodically to breathe. They are able to do this because they are capable of unihemispheric sleep. When we sleep, both of the cerebral hemispheres in our brain are asleep. In manatees, one is sufficiently awake to "tell" the body to surface for air while the other sleeps. Cetaceans (whales, dolphins, and porpoises) also exhibit unihemispheric sleep.

Turtle grass, a sponge, and a sea anemone in Florida

Turtle grass, a sponge, and a sea anemone in Florida

Turtle grass (Thalassia testudinum) is one type of seagrass eaten by manatees in Florida. The common name of the plant refers to the green sea turtle (Chelonia mydas), which eats the seagrass.

Daily Life of Manatees

Manatees spend much of their day feeding on vegetation. They sleep on the bottom of their aquatic habitat or while suspended near the surface of the water. Apart from the relationship between a mother and her calf, the animals are frequently seen alone (except when they are in their winter habitat), though as the FWC says, "they do socialize when other manatees are encountered."

The animals eat many types of plants, but seagrasses are the major component of their diet. Seagrasses (or sea grasses) are related to the grass species that grow on land. Unlike their relatives, their bodies are supported by water currents instead of specialized internal tissues. Like their terrestrial relatives, however, they have roots, leaves, and veins, and they produce flowers and seeds. The Florida Museum says that turtle grass is the most common species of seagrass in the area. Manatee grass (Syringodium filiforme) is the second most common species.

Manatees often seem to be curious about the world of humans, which can sometimes cause problems for them. They overwinter in warm areas of water in Florida. These areas include ones around certain springs and the discharge channels from power plants. Large groups of the animals may be seen in these areas during winter. People planning to visit one of the overwintering areas to see and photograph the manatees should check the rules before they do so. As I think most people would agree, it’s important not to disturb or harass the animals.

Seagrasses can form dense underwater meadows, some of which are large enough to be seen from space. Although they often receive little attention, they are one of the most productive ecosystems in the world.

— Smithsonian Ocean, Pamela L Reynolds

Reproduction and Lifespan

The animals are ready to reproduce when they are around five years old. Gestation lasts for around thirteen months. The female generally gives birth to only one calf in a mating season. The calf feeds on its mother’s milk for approximately two years. The mother produces a new calf every two to five years.

The mother's teats are located just behind her flippers. The commentary accompanying the video of the nursing animals above says that one calf is older than the other one. They aren't twins. According to the commentary, the older calf might be the mother’s or might have been adopted by her.

The oldest animal in captivity was named Snooty. He died in 2017 at the age of 69. It's unlikely that manatees live as long as Snooty in the wild, where multiple threats are present. Snooty’s death was caused by a mistake in the aquarium where he lived. He might have lived significantly longer if this problem had been avoided. An underwater door that was normally bolted shut was loose. Snooty and his companions travelled into an enclosed area. His smaller companions were able to return to the tank, but Snooty was trapped in the area and drowned.

Snooty when he was 63 years old

Snooty when he was 63 years old

It’s important to note that wild manatees shouldn’t be approached as Snooty is in the photo above. Snooty spent his life in captivity and was a special case.

Population Problems

The Florida Fish and Wildlife Conservation Commission says that in 2021 between January 1st and July 2nd, 841 manatee deaths were reported. This broke the previous record of 830 deaths reported for the entire year of 2013. The 2013 total was largely produced by an outbreak of red tide. Red tides are caused by population explosions of harmful algae, or algal blooms. The algae produce toxins, and their cells cause the water to change colour.

Biologists believe that the main cause of the manatee deaths in the first half of 2021 was starvation. They say that pollution is killing the sea grass that the animals eat. The pollution exists in the form of nutrient runoff from fertilizers used on land and from a facility that once produced them. The excessive quantity of nutrients causes algal blooms that cover sea grass and prevent their growth. Like land grasses and other green plants, sea grasses must absorb light in order to produce their food via photosynthesis. The algae also cloud the water and decrease the amount of light that enters it, which further decreases the chance of photosynthesis occurring.

Additional factors are believed to be harming the animals. Leaks from sewers and septic tanks are contributing to the pollution in areas where manatees live. Speeding boats are also affecting the animals. They are often injured by boat strikes. At the time when The Guardian published the article mentioned in the “References” section below, 63 animals had died from boat strikes in 2021.

If there is no sea grass for the manatees, there is also no sea grass for other species. The fact that manatees are dying from starvation signals there is something very wrong with the water quality.

— Martine de Wit, veterinarian, via the Smithsonian Magazine (with respect to the Indian River Lagoon)

An Uncertain Future

Manatees are large animals and therefore require a large amount of food. The situation in the Florida region is worrying for their sake. The decline in water quality may also be worrying with respect to other organisms in the area.

For a long while, manatees were classified as endangered in Florida. In 2017, their population had increased and they were reclassified as vulnerable, which is a less serious category. Some researchers want the animal to be returned to the endangered category. If the current problems continue, the population as a whole may soon be in serious trouble. That’s a sad state for such a lovely and interesting animal. It’s also a sad reflection on human behaviour, which seems to be a major contributor to the animal’s problems.

References

  • Information about the animals from the Florida Fish and Wildlife Conservation Commission
  • Anatomy of a manatee from NOAA (National Oceanic and Atmospheric Administration)
  • West Indian manatee facts from the National Wildlife Federation
  • Unihemispheric sleep information from Nature and Science of Sleep
  • Information about seagrass from The Smithsonian
  • Seagrass species profiles from the Florida Museum
  • In memory of Snooty from the Bradenton Herald
  • Red tide information from NOAA
  • Record number of manatees die from The Guardian (The margin of this article contains a link to another article written two months earlier that contains additional information about the manatee problem.)
  • Florida’s manatees are dying at an alarming rate from the Smithsonian Magazine

© 2021 Linda Crampton

Comments

Linda Crampton (author) from British Columbia, Canada on July 20, 2021:

I’m very glad to hear that you’re feeling better! Best wishes for the future, Misbah.

Misbah Sheikh from The World of Poets on July 20, 2021:

Yes, am feeling much better, Linda. Thank you so much for your kindness.

Many Blessings and Love to you, dear friend

Linda Crampton (author) from British Columbia, Canada on July 20, 2021:

I hope the manatee’s problems are solved, too. Thank you for the visit, Misbah. I hope you’re feeling better and stay healthy. Blessings to you.

Misbah Sheikh from The World of Poets on July 20, 2021:

Linda, thank you for sharing this fascinating information about manatees. It's an interesting creature. I sincerely hope that something can be done to help these animals survive. Sadly, pollution is a major issue.

Stay safe and healthy

Blessings and Love

Linda Crampton (author) from British Columbia, Canada on July 20, 2021:

I agree. They are interesting and lovely animals. Thanks for commenting.

Goh Tong Keat from Malaysia on July 20, 2021:

They are so adorable!

Linda Crampton (author) from British Columbia, Canada on July 19, 2021:

Hi, Adrienne. It is sad that the population of the animals is decreasing. I hope they are helped.

Adrienne Farricelli on July 19, 2021:

I am not very familiar with manatees, so learning about this species was interesting. It's sad that the numbers of manatees in Florida are lowering. I hope to get to see some specimens on my next trip there.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you very much for sharing your experience, Peggy. Unihemispheric sleep is an interesting phenomenon, especially compared to the way in which we sleep.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you for sharing your experience, Fran. The idea of people deliberately running into manatees is horrifying. I appreciate hearing from someone who has lived in Florida.

Peggy Woods from Houston, Texas on July 18, 2021:

We have gotten to view some of those manatees in Florida. I surely hope that they survive! I learned a new word reading your informative article, and it is "unhemispheric sleep."

fran rooks from Toledo, Ohio on July 18, 2021:

Alicia, wonderful article. I lived in Florida for many years and my husband were in a boat and many times watching with sadness those boaters who ignored the NO WAKE rules and running into the slow manatees. We, along with pollution are the problem. Thank you, Alicia.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

I love your statement about us being the virus and the vaccine for Earth. Thank you for sharing it. I hope you have a wonderful day, too.

Chrish Canosa from Manila Philippines on July 18, 2021:

Sadly but that's true. We are the planets virus, but we are as well the vaccine. (My first unfinished comment was the Greek mythology you added about sirens involving lonely sailors which was mistakenly for mermaids)

Have a wonderful day!

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you for the second comment and for sharing the information, Chrish. Water pollution is a major problem. Some of the effects of humans on the planet are very worrying.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you, Chrish. I hope you have an enjoyable day.

Chrish Canosa from Manila Philippines on July 18, 2021:

It's not done yet HAHA, pardon for that Ms Alicia.

Water pollution is a Global issue, while 1.1 billion people lack access to water the rest who are blessed enough to have it is trying their best to ruined it.

Thanks for sharing your knowledge with us!

Have a wonderful day again! Here's our power hugs!!!

Chrish Canosa from Manila Philippines on July 18, 2021:

A wonderful day to you Ms Alicia!

I've learned a lot from this article and I thank you for that. Lonely sailors

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

I hope you have a wonderful day, too, Chitrangada. Thank you for the kind comment.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you for sharing the information, Bill. I was sad to read that most of the animals that you have seen have propeller scars. We need to share the habitat with manatees and enable them to live without harm.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Your underwater achievements are impressive, Manatita. I appreciate your comment very much. I hope you have a great week.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Hi, Rosina. I hope that manatees are helped, too. I appreciate your visit.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Hi, Dora. There are some fascinating aspects to the biology of the manatee. I agree with you. They deserve to be appreciated, not endangered. Thank you very much for the comment.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Hi, Devika. Yes, a lot needs to be done to help the world and its inhabitants, including the manatees. I hope the animals get the help that they need.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you for sharing your experience, Pamela. I hope more is done to help manatees.

Linda Crampton (author) from British Columbia, Canada on July 18, 2021:

Thank you very much for commenting, EK. I hope you stay safe and healthy, too.

Chitrangada Sharan from New Delhi, India on July 18, 2021:

A very well written and informative article about the Manatee or the sea cows. Interesting to know that they are herbivores animals.

Pollution is a major cause of concern for all living beings, whether in water bodies or atmosphere. I hope something can be done to save these species.

Thank you for sharing a wonderful and educative article.

Have a wonderful day.

Bill De Giulio from Massachusetts on July 18, 2021:

What is happening to the manatee in Florida is very sad. We have encountered them many times while kayaking and they really are curious about humans. Unfortunately some humans decide to do stupid things like jumping into the water and trying to touch them. Most manatees in Florida that we have seen also have propeller scars on their back, which is sad to see. The pollution issue affecting the sea grass needs to be addressed soon as the species cannot be sustained without their primary source of food.

manatita44 from london on July 18, 2021:

Beautifully written as always, Alicia.

Missed you a lot! You're OK?

I was proud to read that Manatees can come all the way from West Indian shores. Sweet!! They also do things in their sleep! I won't mind a tad of 'somnabulism' of moments into the garden to adorn my soul with roses. Then I can return to bed alive. Ha-ha. (Joke)

I enjoyed a couple of videos. I liked seeing them eating sea grass and of course the mating. Intriguing! They also stay under water quite long! I used to do four minutes once. I trained 3 years to swim the English Channel, and my lungs were in great shape.

Manatees are cute creatures ... mammals that should not be endangered. Let us hope.

Rosina S Khan on July 18, 2021:

It was intriguing to know about the manatees, Linda. I am sorry to know they are becoming less in number. I also hope they can be helped out before it is too late. Thanks for sharing.

Dora Weithers from The Caribbean on July 18, 2021:

"In manatees, one is sufficiently awake to 'tel' the body to surface for air while the other sleeps." Amazing! Thank you for the interesting facts about the manatee's brain activity and other distinctive features. They deserve to be appreciative, not endangered.

Devika Primić from Dubrovnik, Croatia on July 18, 2021:

It is sad to know of the Manatee endangered. You state valuable information about the manatee. A lot is required to save the earth from being destroyed and the species that live in water. Your hub is interesting about what most people ignore or don't know of. Hope this helps otehrs to learn from what is not spoken of. This hub lets us know what is going on in our world.

Pamela Oglesby from Sunny Florida on July 18, 2021:

This is a very interesting article, Linda. You have provided so much good information, and the manatee is an interesting mammal.

Several years ago my husband and I had a boat. We lived in Jacksonville, FL. and when you go out on the St. John's River there are signs that warn you to be careful due to the manatee population. That doesn't not solve the problem with their though and I hope something can be done to see that problem. I know this governor has addressed some of the problems with the water but it may not be enough.

I really enjoyed reading this article, Linda.

EK Jadoon from Abbottabad Pakistan on July 18, 2021:

Manatees are really wonderful and unique animals. That was an informative read, Alicia. Thanks for sharing. It's interesting that their ancestors lived on land.

Stay safe and healthy...

Linda Crampton (author) from British Columbia, Canada on July 17, 2021:

Thanks for commenting, John. The situation is sad and worrying. Like you, I hope that something can be done to help the animals.

John Hansen from Gondwana Land on July 17, 2021:

Thank you for sharing this interesting information about the manatee, Linda. It is a sad fact that they endangered (like so many other animal species) due to the loss of sea grass and poor water quality and pollution. I hope something can be done to address this before it is too late.

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