Nearly 1,000 Manatees Converge on Florida State Park to Keep Warm in Record-Breaking Sighting

A group of manatees is called an aggregation—and visitors to Florida’s Blue Spring State Park north of Orlando have just witnessed some of the largest aggregations ever recorded at the site.

Hundreds of the threatened mammals—affectionately known as “sea cows” for their slow-paced swimming and gentle giant demeanor—have been wintering together in the park’s warm springs throughout January. Huddling and resting in the shallow, turquoise waters near grassy riverbanks and mangrove trees, the manatees are riding out the cold. Rangers rang in 2024 with an official Blue Spring record, counting 736 manatees in the park on New Year’s Day, and impressive totals between 200 and 700 manatees continued in the following weeks, updated routinely on the park’s Instagram.

But perhaps no morning was more memorable than January 21, when workers counted 932 manatees, surpassing the month’s earlier aggregation by nearly 200 animals. “Record breaking morning at Blue Spring State Park,” the park shared on Facebook. “Happy manatee season everyone!”

While the aggregation was historic, it isn’t entirely charming. In Florida’s cool winter months, manatees—which live in freshwater and saltwater habitats, preferring calmer waters above all—can struggle to stay warm. Huddling with others and sharing body heat is necessary for their survival.

Despite what many people think, manatees are relatively lean, and their ho-hum behavior isn’t a product of laziness, but of energy conservation. Though they appear insulated by a thick layer of blubber, the animals actually have just one inch of fat. This, combined with their slow metabolisms and warm-blooded bodies, can make cold snaps—as Florida has recently faced—quite dangerous.

Manatees cannot endure temperatures below 68 degrees Fahrenheit for long, reports WFLA’s Kaycee Sloan. And water temperatures below 60 degrees Fahrenheit could send the animals into cold stress, a condition in which the tail or fins don’t receive enough blood, and patches of skin might flake off.

On the record-breaking day, temperatures in the nearby St. John’s River, a manatee hotspot with channels that flow throughout the park, dipped to a near-deadly 58 degrees. In response, the sea cows migrated to the park’s springs, which tend to be 72 degrees year-round.

“This is very unusual,” Cora Berchem, a manatee research associate at the nonprofit Save the Manatee Club, tells BBC News’ Mia Taylor. “I was definitely expecting to see a high number, but not so many, so quickly.”

Though such chilly weather can have grave implications for the marine mammals, the fact that so many of them were able to find the park and its naturally warm waters “is really encouraging,” Berchem tells NPR’s Diba Mohtasham.

Blue Spring State Park has become a haven for manatees over the past few decades, with its population jumping from just 36 in the 1970s, to consistently more than 700 today, per NPR.

Between 7,000 and 11,000 manatees live across Florida—a significant increase from 50 years ago, when they numbered only 1,000. Still, the species remains listed as threatened under the Endangered Species Act, though some are petitioning to get it reclassified as endangered. More than 500 manatees died in 2023, according to a preliminary report, and a number of challenges to the species’ survival remain.

Underwater Manatee-Cam at Blue Spring State Park powered by EXPLORE.org

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In recent years, polluted waters and an influx of toxic “red tide” algal blooms have decimated the population of Florida seagrass—manatees’ main source of food—and led to the starvation and death of hundreds of animals. Manatees may also be seriously hurt or killed by boat strikes.

But food is abundant in Blue Spring State Park’s clear waters, and it’s one of Florida’s few places where watercraft are prohibited during the winter months.

“The fact that [manatees] are choosing to be at Blue Springs shows how important of a site it is and what a manatee is really looking for, for survival,” Monica Ross, a manatee and conservation researcher for the Clearwater Marine Aquarium, tells NPR.

Christian Thorsberg | READ MORE

Christian Thorsberg is an environmental writer and photographer from Chicago. His work, which often centers on freshwater issues, climate change and subsistence, has appeared in Circle of Blue, Sierra magazine, Discover magazine and Alaska Sporting Journal.