Manatees, long considered among Florida‘s most beloved and enchanting inhabitants, are not native at all, and only came to the Sunshine state for warm temperatures and clear blue waters like any other visitor, researchers have found.
The surprise revelation by scientists at the University of South Florida (USF) and George Washington University (GWU) upends decades of thinking about the origins of the threatened species, once plentiful around the Florida peninsula, the Gulf of Mexico and Caribbean.
The finding could also offer a pathway to survival of the creatures known as sea cows, of which fewer than 9,000 are believed to inhabit Florida’s waterways.
Thomas Pluckhahn, professor of anthropology at USF, pointed to a remarkable rebound in numbers of bowhead whales, conservation efforts fuelled at least in part by a better understanding of the history and geography of that species.
“Biologists often try to set targets for management based on historical baselines, but a lot of times those are just assumed rather than demonstrated. They often put a large priority on native species,” he said.
“Historical records could be useful for manatees‘ management, maybe trying to take a more granular approach to the population histories and using those to set targets. Studies of other species like bowhead whales have recognized populations are differential, they’ve been differentially impacted by histories of whaling and exploitation.”
Pluckhahn, who co-authored the study with the GWU archaeology professor David Thulman, likened manatees to so-called snowbirds, the colloquial name attached by locals to seasonal visitors to Florida from colder climes.
He said Florida’s waters were once too frigid for manatees because of the little ice age, a period of intermittent cooling lasting from around 1300 until the mid-1800s. The authors believe only at its conclusion did manatees begin travelling north in greater numbers, and not during Florida’s colonial days from the 16th to 19th centuries when it was assumed settlers from Spain and Britain might have hunted them.
“Manatees are very sparsely represented in archaeological and archival records before the late 1700s and the most likely explanation is that they were present only occasionally,” Pluckhahn said.
“There are a few documented examples of manatee bones in the archaeological records of Florida, most manufactured into tools or ornaments, which suggests they might have been traded from the Caribbean.
“It’s also possible they were present but people didn’t hunt them, but I just don’t think that kind of taboo would have lasted 10,000 years or so, and it doesn’t explain why they wouldn’t show up on Spanish sites or in Spanish records.
“And we also don’t see any art. If manatees were important to Native Americans, we might expect them to be represented. Other animals are represented in Native American art in Florida: panthers, dolphins, things like that. But we don’t see manatees.”
It was this anecdotal lack of representation for a species supposedly so ingrained in Florida’s historic culture that encouraged Puckhahn and Thulman to collaborate on their research. They studied dozens of pre-colonial archaeological records, and archives from explorers and settlers who landed in Florida from the mid-1500s onwards, and found that references to manatees were not showing up in any significant numbers.
Beginning in the 1920s, they said, media reports became more common of manatees being routinely spotted along the east coast of Florida, from Miami to St Augustine, and “becoming more plentiful” along the Gulf of Mexico coast and in Tampa Bay by the 1950s.
“There are still cold spells, and that’s a limiting factor for manatees,” Pluckhahn said. “But climate change was accompanied by changes to the landscape that created warm-water refuges, things like canals and yacht basins, and that’s where people spotted manatees most commonly in the late 1800s and early 1900s.
“Then when power production ramped up, beginning in the 1920s power plants became the principal warm-water refuge outside of natural springs.”
Pluckhahn notes that he and Thulman are not biologists, but hopes their research will help the decision-making process as efforts to restore the imperilled species continue.
“As we’ve highlighted, some of the earlier manatee refuges were kind of passive, solar, shallow-water features, and we don’t know if it’s possible to create more of those or to make existing ones more manatee friendly, but we are going to need more warm-water refuges for manatees as the fossil fuel plants close,” he said.
The US Fish and Wildlife Service (FWS) has been mulling whether to restore to manatees the “endangered” status removed during the first administration of Donald Trump in 2017. The service announced last month that because of hurricanes Helene and Milton this year it was extending until late January a public comment period over revised or new critical habitat designations for two subspecies, the Florida manatee and the Antillean manatee in Puerto Rico.
“The future of the Florida manatee is uncertain, and the continued loss of essential warm water and foraging habitat poses a significant threat to its long-term survival,” an alliance of advocacy groups, including Defenders of Wildlife, the Save the Manatee club and the Center for Biological Diversity, told FWS in a statement.
Conservation efforts, they said, “have been largely focused on the immediate need to rescue stranded manatees, rather than on engaging with the service’s long-term policies to ensure the survival and recovery of the species”.
This article by Richard Luscombe was first published by The Guardian on 2 January 2025. Lead Image: A manatee swims in Three Sisters Spring in Crystal River, Florida, in 2022. Photograph: Dave Fleetham/Design Pics Editorial/Universal Images Group via Getty Images.
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