Manatees, also known as sea cows, are gentle giants that inhabit coastal waters and rivers. With their bulbous bodies, whiskery snouts, and paddle-like tails, they look harmless enough. But have these slow-moving marine mammals ever attacked humans before?
If you’re short on time, here’s a quick answer: while extremely rare, there are a few documented cases of manatees acting aggressively toward humans, likely out of fear or feeling threatened.
The Gentle Nature of Manatees
Manatees are Herbivores
Manatees are completely herbivorous mammals that only consume aquatic vegetation. Their diet consists primarily of seagrass and freshwater vegetation such as hydrilla and water lettuce. Occasionally, manatees have been observed eating acorns from overhanging oak trees.
Being herbivores, manatees do not prey on other animals for food. This contributes to their docile and gentle temperament.
Manatees Have Few Natural Predators
In the wild, manatees have very few natural predators, mainly due to their intimidating size. The average adult manatee can reach up to 13 feet long and weigh up to 1,300 pounds. Historically, sharks and crocodiles occasionally preyed on baby manatees, but attacks were rare.
However, with the decreasing manatee population, predation from sharks and crocodiles poses more of a threat now.
The biggest threat to manatees comes from humans through watercraft collisions and habitat loss. So while manatees are generally defenseless creatures, their size protects them from most predators
Threats from Humans and Habitat Loss
As mentioned previously, one of the largest threats to manatees is collisions with motorized boats and ships. Manatees swim slowly, often basking near the surface of the water. Unfortunately, their slow pace and shallow positioning makes them highly vulnerable to fast-moving watercraft.
According to Florida government statistics, over 300 manatees died from watercraft collisions in 2021.
In addition to boat collisions, human development has led to a significant loss of crucial manatee habitats like seagrass beds and sheltered waterways. The degradation of their ecosystem through algal blooms and pollution from agricultural runoff also poses a major threat.
Evidence suggests that manatees lack the capability to adapt quickly to habitat loss and human activity expansion along coastlines. Therefore, they remain extremely vulnerable to extinction without strict conservation measures.
Cases of Manatees Acting Aggressively Toward Humans
Documented Incidents Are Rare
Despite their large size and intimidating appearance, attacks by manatees on humans are extraordinarily uncommon. In fact, there are only a handful of documented cases of these gentle giants exhibiting aggressive behavior toward people.
According to records kept by the Florida Fish and Wildlife Conservation Commission (FWC), fewer than 15 incidents involving aggressive manatees have been reported in the last 50 years (source: FWC Manatee Mortality Statistics).
The FWC classifies most cases of purported manatee aggression as “threatened” interactions rather than outright attacks. These incidents typically involve a manatee swimming toward or chasing a swimmer while vocalizing or making abrupt movements.
However, actual physical contact between manatees and humans is very rare.
Aggressive Behavior Often Linked to Fear or Feeling Threatened
On the infrequent occasions where manatees do lash out at humans, experts believe the behavior is usually triggered by the animal feeling afraid, surprised, or threatened in some way rather than actual aggression or a desire to attack.
These gentle sea cows tend to be slow-moving and extremely wary of humans unless they have become accustomed to people through programs like swimming with manatees.
Documented incidents of aggressive manatee behavior have almost always involved humans unintentionally startling a manatee by doing something like suddenly jumping into the water near them or getting too close to a cow that has a calf. The manatee may perceive this as a threat to itself or its baby.
Other Possible Explanations
In addition to feeling frightened, threatened, or protective of a calf, researchers have surmised that unusual manatee behavior toward humans could also be due to:
- The manatee being rescued or handled by biologists multiple times, making it less wary of humans
- Habituation to humans feeding or touching manatees
- Debilitating health issues affecting the manatee’s cognition or behavior
- Orphans or rescued calves that have imprinted too much on humans
So while manatees don’t intentionally attack people, incidents can happen if they feel surprised, scared, or aggressed against. But again, documented cases of truly aggressive manatee behavior remain exceptionally rare, especially given the thousands of friendly human-manatee interactions that occur in Florida’s waters every year.
Overall, any hazards these peace-loving marine mammals may pose to us swimmers and boaters is greatly outweighed by the threat we pose to them through habitat loss and collisions with watercraft.
How to Avoid Conflicts with Manatees
Give Manatees Space
When boating, paddling, or swimming in waters where manatees are present, it is crucial to give these gentle giants plenty of space. Manatees can be startled if approached too closely, especially mothers with calves. Give manatees a wide berth of at least 50 feet when possible.
This gives them adequate space to surface, breathe, and move about freely without feeling threatened.
If a manatee does approach your boat out of curiosity, simply let it be. Do not try to touch or interact with wild manatees. Passive observation from a safe distance is the best practice. Limit noise pollution as well by turning off music and keeping voices soft when manatees are near.
Never Provoke or Harass a Manatee
It should go without saying, but it is illegal to hunt, capture, collect, or in any way harass or provoke manatees, thanks to their legally protected status. Do not throw objects at manatees, chase after them, or attempt to feed them. This includes no giving them water, lettuce, or any other foods.
Such harassment causes distress and alters their natural behaviors. Well-meaning interactions with wild animals often do more harm than good. Leaving manatees to their business is the best way we can “help” them.
Be Cautious Around Calves
Mother manatees with calves require extra precautions. They are more likely to become defensive if they perceive humans as a threat to their babies. Stay at least 100 feet away from any pairings of adult and juvenile manatees.
If you accidentally separate a mother and calf due to boating activity, cut your motor and patiently wait for them to reunite. Never come between them. Mothers are extremely protective and may exhibit dangerous behaviors like ramming or flipping boats if distressed.
By giving manatee families plenty of room, moving slowly, and minimizing disturbances, we reduce the very small risk of retaliation from these otherwise peaceful creatures.
Conclusion
While manatees are generally peaceful creatures that mean no harm to humans, in very rare cases, they have exhibited aggressive behavior when feeling threatened or frightened. By giving these gentle giants plenty of space, refraining from antagonizing them, and respecting protective mothers with calves, we can appreciate manatees safely in their natural habitats.
