Manatees

Manatees are one of the most famous animals in Florida, and are hugely popular.

Manatee ecotourism brings large numbers of people to the Crystal River area and other manatee hotspots every year.

Sadly, the large number of visitors and some irresponsible tour operators are endangering manatees, which are already imperiled and whose existence is threatened.

Manatee Tours

Expert guided kayak tours are one of the best ways to see manatees.

Knowledgeable guides often know the best place to see manatees. They know how to view them reliably, safely and without disturbing manatees’ natural behavior.

Visitors should do research to ensure tour operators are respectful of nature and that operators using best practices. Visitors should be aware of red flags to watch out for before going.

Reputable tour operators should never advertise or promote touching manatees, or any other activity which may alter their natural disposition.

Swimming with Manatees

Swimming with manatees is controversial.

Many people argue that swimming with manatees is good because it creates a love for manatees and helps sway public opinion toward conservation efforts.

Experts agree that swimming with manatees if not good for them, for several reasons. The biggest reason is because it creates stress for manatees and may drive them out of their natural habitats, which they need for survival. It alters their natural behavior and trains them to approach humans.

Becoming comfortable with human presence may disturb natural behavior in unexpected ways. It may incentivize manatees to approach boats, which can lead to their death or severe injury.

Many swimmers are not graceful in the water. They may kick, splash and scare manatees accidentally while trying to stay afloat. When manatees are frightened they may leave the area, and may never return if they feel it is unsafe. Losing their habitat will lead to death if they cannot find access to warm water during cold weather.

Human interactions may also negatively impact mating behaviors, the dynamic between mother and calf, and other social roles.

Swimming with manatees is a sad reality. It should not be allowed because it is bad for the wildlife. But, it is.

If you are considering swimming with manatees you should ensure that your tour operator respects the animals and their right to exist peacefully.

The only way people should interact with manatees is to observe them from a respectful distance.

Nobody should touch manatees, crowd them, block their path of movement, or interfere with the manatee in any way.

Many responsible ecotourism operators do not allow swimming with manatees, but only provide passive observation from a boat, kayak or paddle craft.

If you observe people behaving inappropriately with manatees you should report them to authorities because it may lead to manatee deaths.

Are Manatees Dangerous?

Manatees are generally not dangerous, but they can be, and may cause human injuries.

Manatees are large, wild animals. They can weigh thousands of pounds. They can quickly accelerate when frightened. They may accidentally crush or hurt people if they are too close and there is a sudden disturbance. Manatee tails are also very powerful and may pose a danger to swimmers who are too close in the water.

Diet and Physiology

Manatees are 100% herbivorous, meaning that they only eat plants and vegetation.

Manatees can grow to more than 13 feet long and can weigh more than 3,500 lbs.

Baby manatees are approximately four feet long and weigh approximately 60-80 pounds when they are born. Baby manatees grow and gain weight quickly because they nurse and consume high-fat milk from their mothers. They remain with their mothers for one or two years. During this time mother manatees help keep their calves safe and continue to nurse.

Manatees have heavy bone structures which counteract the buoyancy of their large lungs, which are located on their backs. This combination allows them to be perfectly balanced and remain stable in the water while resting and swimming.

Manatees move by flapping their large rear paddle up and down to propel themselves forward.

They can swim quickly and are very graceful underwater.

Manatees generally travel at about a human walking speed of 3-5 miles per hour. They can move in short bursts of up to 15 miles per hour.

While swimming manatees’ tails often create a flat, circular pattern on the surface of the water. This pattern can help make it easier to see manatees when they are underwater.

Manatees have six cervical vertebrae, unlike all other aquatic mammals which have seven vertebrae. As a result, manatees do not have a neck and cannot turn their heads. They must turn their entire body to see around themselves.

Can Manatees Bite?

Manatees have teeth, but they cannot be used for biting.

Manatee teeth are all molars, and are located far back in their mouths. They are only used for grinding up sea grasses and aquatic vegetation.

Manatees’ teeth are constantly worn down by grinding action and are replaced frequently. They are known as “Marching molars”. When a new tooth grows into the back it pushes the old one out of the front.

Manatees grow new teeth at a rate of approximately one centimeter per month.

Manatees have very flexible and articulate mouths thanks to a feature known as a “Prehensile upper lip”.

They can move each side of their mouth and lips separately, which allows them to grab seagrass efficiently. It is similar to an elephant’s trunk.

Manatees also have protective membranes over their eyes for protection while underwater, although they do not have eyelids.

Instead of eyelids, manatees close their eyes in a circular, rotating movement. It’s similar to the round aperture of a camera. They can see well underwater and in both light and dark conditions.

Manatees don’t have external ear lobes, but they do have good hearing.

They have large internal ear bones which conduct sound waves. They do not generally make very much noise, but do sometimes scream when in distress. Mothers and calves are known to use sound to communicate with each other.

They are known to make more noise, possibly to locate each other or communicate, when in murky water conditions.

Manatees have grey, leathery skin which can often turn green or brown from algae growth in freshwater. They may also grow barnacles on their backs after spending a lot of time in salt water.

Manatees have sensitive hair and whiskers called vibrissae which covers their bodies, especially on their mouths and snouts.

These hairs are important sensory instruments for manatees. It helps them remain aware of their surroundings, especially because they cannot turn their heads.

Manatees’ mouth whiskers are also important because they use their mouths to kiss and socialize with other manatees.

Manatees can live for up to 65 years but most wild manatees do not survive past their early twenties.

Biology and Evolutionary History

The latin name for the Florida Manatee is Trichechus manatus latirostris. They are classified as part of the Sirenian bilogicial order.

Sirenians were land animals at one time. As they evolved their back legs turned into monofin tail flukes, or paddles. Their front limbs turned into pectoral flippers.

There are two families of sirenia: Dugongidae and Trichechidae.

Dugongidae consists of the Asian Dugong and another species which was quickly hunted to extinction, the Steller’s sea cow.

Manatees belong to the Trichechidae family. There are several subspecies, including the Amazonian manatee, the West Indian manatee, the West African manatee and the Florida manatee.

Florida manatees have evolved into their own subspecies and are distinct from other subspecies of manatee. Florida manatees have a subtle skull variation which makes them unique from other manatees.

Many people guess that manatees are related to walruses, but they are not. Manatees are most closely related to elephants. They have cute toenails on their flippers which closely resemble elephant toenails.

Manatees have unused bones in their skeleton which are relics, or left over, from when they were land mammals. Pelvic bones are one example, among others.

The bones inside manatee flippers are very similar to human hands. They have fingers and flexible, articulating joints.

Manatees use their flippers as if they were hands. They use them to hold things, bring food to their mouths and for moving through the water.

Manatee Behavior

Although they are often seen in large groups during winter, manatees are generally solitary.

They do not tend to travel or live together, except for mothers and calves, or when they are all gathered together in a warm water refuge. They do socialize with other manatees, though.

Manatees breathe air, and breathe through nostrils on the top of their snout. When they need to breathe they rise briefly to the surface, exhale, inhale, then dive again.

Their nostrils have protective coverings and form a waterproof seal when they go underwater.

Manatees usually hold their breath for 5-10 minutes at a time, but can hold their breath for as long as 20 minutes.

They do not dive very deep and usually stay in shallow water near shore.

This makes them vulnerable to being run over by boats and sliced by boat propellers.

Manatees spend most of their time resting, eating or socializing with other manatees.

They spend approximately 8-12 hours a day sleeping, 8-10 hours eating, and the rest is spent socializing or migrating.

Because they graze on grass all day, manatees are often referred to as “sea cows”.

Manatees can eat as much as 100 pounds of vegetation per day, which is often 10-15% of their overall body weight.

100 pounds of vegetation would be approximately three bath tubs worth of spinach leaves, for comparison.

They typically rest while floating weightlessly in the water, or sometimes laying at the surface or the bottom. They typically expend very little energy while resting.

During warm winter months some manatees may migrate far away from Florida as they forage for aquatic vegetation. Some go as far as Georgia on the east coast and as far west as Texas. They return to Florida as cold winter months approach.

Mating and Reproduction

Florida Manatees do not breed according to seasonal patterns. Their mating behavior depends on when a female manatee becomes sexually mature or when they do not have a calf.

Their mating behavior generally consists of a group of males pursuing a female when she is fertile, or in estrus. Females mate with multiple male partners. The most persistent male typically achieves fertilization.

The mating pursuit can be exhausting; females often retreat to shallow water to escape the chase. People often think that mating groups are stranded or in distress, and may disturb the manatees mating behavior.

Female manatees generally have approximately one calf every three years. The pregnancy lasts approximately one year.. Manatees, like all mammals, nurse their offspring with milk.

Mothers nurse their baby manatees for one to two years. Manatees’ mammary glands are located under their front flippers, which sort of looks like an armpit.

Warm Water

Manatees migrate into warm spring water, rivers and other areas during cold winter months. They often gather in large numbers around the headspring of natural springs.

They gather in tight groups to stay close to warm water, conserve body heat and minimize their energy expenditure.

Florida is at the north boundary of the Manatee’s natural geographical range. During cold winter months Florida’s ocean water becomes too cold for manatees to survive. Water below 68 degrees will kill or injure manatees due to cold stress syndrome.

Without warm water refuges manatees could not survive in many areas of Florida.

Threats to Manatees

There are many threats which are dangerous to manatees survival:

• Habitat destruction
• Watercraft collisions
• Starvation due to seagrass destruction
• Entanglement in fishing gear
• Water Pollution and Red Tide
• And other human-caused dangers

Manatees do not generally have many natural predators.

They are generally too large to be prey for most of the predators, but small, young and injured manatees can be an easier target for crocodiles, alligators and sharks.

Most manatee deaths are due to being run over or sliced by boat propellers.

Many manatees have large, deep scars on their backs from being cut and sliced by boat propellers.

If strong manatees survive the initial cuts and collisions they may be able to heal themselves, or be treated by manatee rescue operations.

Some manatees have been found with many dozens of slice sounds because of repeated boat strikes.

2021 has been the deadliest year on record for manatees.

Huge numbers of manatee have starved to death because of seagrass shortages which are caused by water pollution, red tide and runaway algae growth.

Manatee survival is also threatened by other factors. They are at risk of starvation due to seagrass die offs and water pollution. They are also losing access to warm-water refuges, which are critical to their survival, as springs and rivers are blocked, altered and developed. Some warm-water power plant refuges may also disappear as coal fired power plants are decommissioned.

Manatees were hunted by native Americans and early settlers in Florida.

Their population was stable for thousands of years while being hunted by small numbers of native Americans, but were quickly hunted to near extinction as soon as American settlers arrived in Florida in the late 1800s.

If manatees were not protected they would almost certainly not exist today. They would have been hunted to extinction very quickly. One example is already extinct, and shows what will happen to manatees without protection.

The Steller’s Sea Cow is a close relative of the Florida manatee. It was hunted to complete extinction soon after being discovered by Russian hunters.

Manatees are mostly defenseless animals.

They are peaceful and do not have any means of defense against predators or harassment.

Protections for Manatees

Humans have recognized manatees’ fragility and need for protection for hundreds of years.

When Florida was under English control in the early 1700s Florida was declared to be a manatee sanctuary.

Florida later passed a law making it illegal to kill or capture a manatee in the 1800s after it became a state. Even at that time biologists were worried that manatees would be hunted to extinction.

More recently, manatees are protected under several laws:

• The 1972 Marine Mammal Act
• The Endangered Species Act of 1973
• The Florida Manatee Sanctuary Act of 1978

The Florida Manatee Sanctuary Act of 1978 made all of Florida into a manatee sanctuary. It also designated the manatee as Florida’s official state marine mammal.

There are state and federal guidelines for interacting with manatees. Violating the guidelines is a serious crime.

Violations have been punished with jail time, criminal charges and enormous fines. In recent years manatees have come under greater threat, and their behaviors have changed.

Sadly, manatee abuse and harassment still occurs.