Our state marine mammal, the Florida manatee (Trichechus manatus latirostris), is a subspecies of the West Indian manatee. This gentle, slow-moving creature can weigh more than 3,500 pounds and grow up to 13 feet long. Curious and playful by nature, they may pop their heads up close to kayaks or swim directly toward a snorkeler to get a closer look.
Manatees are sometimes called sea cows because of their size and grazing behavior. Manatees are natural weed-control agents, consuming up to 150 pounds per day of aquatic plants. Manatees are the only completely herbivorous marine mammals, and because they have no predators, they have evolved no defenses.
Manatees prefer shallow water, where they can forage and rest on the bottom. Because they cannot tolerate water temperatures colder than 68 degrees, during the winter they travel to natural warm springs inland or congregate in artificial sources of warm water, such as the power plants in Tampa and Fort Myers.
When manatees swim, they create roundish ripples in the water called footprints. If you look for these, you might spot a nose coming up to breathe. Because they are mammals, manatees need air. Normally, they breathe every 2 to 5 minutes, but may remain submerged for 20 minutes. When manatees surface, they open their nostrils. When they dive, they close their nostrils to keep water out.
Female manatees usually have one baby (rarely twins) every 2 to 5 years. After a 13-month pregnancy, a manatee gives birth to a calf that weighs about 70 pounds and measures 3 feet. The calf stays with its mother for one to two years, nursing from nipples located under each flipper and learning how to forage.
Wild manatees are known to live as long as 50 years, though many die younger due to boat collisions and red tide outbreaks. Snooty, a captive manatee, lived 69 years at the South Florida Museum in Bradenton.
Manatees use their front flippers to steer and to hold vegetation while eating. Their flattened tails allow them to undulate as they swim, so slowly that algae and barnacles attach themselves to their skin.
In 2017, the U.S. Fish and Wildlife Service delisted manatees from endangered to threatened because Florida’s population increased from several hundred in 1967 to 6,250 counted in an aerial survey in 2014. Manatees are still protected by the Marine Mammal Protection Act and the Endangered Species Act, so it is illegal to harass, hunt, kill, capture or feed wild manatees.
By offering lettuce or water to manatees, we invite them near boats, which puts them in danger. More than 85 percent of adult manatees show scars from boat propellers. In 2018, at least 119 manatees died from collision with watercraft.
Manatees ingest seagrasses contaminated with red tide toxins. Thus far, 804 manatees have died in 2018. Red tide contributed to 209 of those deaths. Additionally, seagrass decline, pollution, habitat loss and cold weather all present threats to manatee survival. These threats are likely to grow, given the dramatic increase in projected human populations.
The Marine Mammal Commission believes downlisting the manatee is premature. Thousands of commenters have urged USFWS to keep manatees listed as an endangered species. What a great gift to our grandchildren it would be to continue to share our world with manatees.