Overview
Manatees are gentle, slow-moving aquatic mammals often called "sea cows." They belong to the order Sirenia and are divided into three species: the West Indian manatee (Trichechus manatus), the Amazonian manatee (Trichechus inunguis), and the West African manatee (Trichechus senegalensis). These herbivorous mammals play a vital role in maintaining healthy aquatic ecosystems by grazing on seagrasses and aquatic vegetation. Despite their large size, manatees have no natural predators — their greatest threats come from human activity.
Species & Distribution
West Indian Manatee
Found along the southeastern United States coast, the Caribbean, and the Gulf of Mexico. The Florida manatee is a well-known subspecies that congregates near warm-water springs and power plant outflows during winter.
Amazonian Manatee
The only exclusively freshwater species, living in the rivers, lakes, and floodplains of the Amazon Basin. It is the smallest manatee species and the most difficult to study due to the remote, murky waters it inhabits.
West African Manatee
Found along the coast and in rivers of West Africa from Senegal to Angola. It is the least studied of all manatee species, and population estimates remain uncertain.
Physical Characteristics
Size & Build
Adult manatees typically grow 9–13 feet (2.7–4 meters) long and weigh 800–1,300 lb (360–590 kg). Their bodies are rotund with a large, flat, paddle-shaped tail and two flipper-like forelimbs.
Teeth Replacement
Manatees have a unique dental adaptation called "marching molars." New teeth constantly form at the back of the jaw and slowly move forward, replacing worn teeth throughout their lives.
Breathing
As air-breathing mammals, manatees must surface every 3–5 minutes while active, though they can hold their breath for up to 20 minutes while resting.
Skin & Senses
Their thick, wrinkled skin is covered in fine hairs that act as sensory receptors, helping them detect changes in water currents and nearby objects.
Behavior & Ecology
Herbivorous Diet
Manatees spend 6–8 hours per day grazing, consuming 10–15% of their body weight in aquatic vegetation daily. Their diet includes seagrass, mangrove leaves, and various freshwater plants.
Social Nature
While generally solitary, manatees are not territorial and will congregate in warm-water areas during cold weather. Mothers form strong bonds with their calves, nursing them for 1–2 years.
Migration
Florida manatees migrate seasonally, moving to warm-water refuges like natural springs and power plant discharge areas when water temperatures drop below 68°F (20°C).
Vocalizations
Manatees communicate using chirps, squeaks, and whistles, particularly between mothers and calves. These sounds travel well underwater and help maintain contact in murky waters.
Threats & Conservation
Boat Strikes
Collisions with watercraft are the leading human-related cause of manatee deaths in Florida. Many surviving manatees bear propeller scars from close encounters.
Habitat Loss
Coastal development, water pollution, and the loss of warm-water refuges and seagrass beds threaten manatee survival across their range.
Recent Crisis
In 2021–2022, an unprecedented die-off occurred in Florida's Indian River Lagoon due to starvation caused by massive seagrass loss from water pollution. Hundreds of manatees perished.
Protection
Manatees are protected under the U.S. Marine Mammal Protection Act and the Endangered Species Act. Speed zones in waterways and manatee sanctuaries help reduce boat-related deaths.
