ORLANDO, Fla. – From boat strikes to seagrass loss, Florida manatees are facing existential threats this decade, however, conditions for the gentle sea cow are likely more favorable today than they’ve been in centuries, according to a report published in the journal Plos One.
While manatees are long considered to be one the state’s most adored inhabitants, research suggests they may have only arrived in great numbers starting in the late 1800s.
[RELATED: Hot spots in Florida to see manatees]
Researchers point to a lack of archeological and historical evidence that the species lived abundantly alongside humans on the Florida peninsula from the time of initial human settlement 14,000 years ago to the late 1950s.
How long have manatees frequented Florida?
That’s a difficult question to answer, study co-author David K. Thulman, an adjunct professor at the George Washington University, told News 6.
The researchers relied on documented sightings from Native American residents and European colonists — observations that were sporadically reported and potentially inaccurate since Spanish and French explorers had little experience with these chubby, graceful mammals.
The study also examined fossils and bones from those Precolonial and Colonial days.
“The actual bones of manatees are extremely uncommon on archeological sites,” said co-author Thomas J. Pluckhahn, professor of anthropology at the University of South Florida.
“We do have one or two examples dating back as far as 5,000 years ago, but it seems likely that they were pretty uncommon in Florida.”
What changed?
For one, the warming climate.
“The climate is much warmer than it has been in the past,” Pluckhahn said.
“Part of that is natural climate change. Beginning about 1200 A.D. and continuing into the 1800s, we were in what’s called the ‘Little Ice Age’."
That period of significantly cooler global temperatures may have forced the Florida manatee (one of two subspecies of the West Indian manatee) to remain in warmer Caribbean waters.
The industrial boom of the 1920s brought electricity-generating power stations to several coastal Florida cities, which release warm fresh water used to cool off the steam boiled by burning fuels into natural waterways.
Generations of manatees have relied on that heated water to survive, for example, outside the Orlando Utilities Commission Indian River Plant along U.S. 1 in Brevard County.
Another factor bolstering the modern abundance and migration of manatees in the Sunshine state — is food.
Water plants, such as the hydrilla and water hyacinth, have invaded many Florida waterways providing a tasty snack for the floating herbivores.
“These invasive species were able to support larger manatee populations. I think those two factors coming together as Florida becomes more and more populated and more industrialized led to this growth in population,” Thulman said.
Humans’ shifting relationship with Florida manatees
Before the mid-1950s, the article states the range and population of the Florida manatee were poorly understood and that much of our knowledge surrounding the mammal’s ecological history often relied on speculative, outdated science.
Previous reviewers assumed the species used to be abundant and widespread before modern hunting and earlier exploitation by Indigenous peoples.
But the study’s co-authors argue the scarcity of sea cows was not due to overhunting, but rather because of their infrequent migrations from the Caribbean and the natural climate conditions of the time.
Florida’s modern protective relationship with manatees is benchmarked in an 1893 state law when leaders made it illegal to hunt or capture the animals.
In 1975, the gentle giants were declared the state marine mammal of Florida.
For nearly 50 years, manatees were classified as an endangered species, only being reclassified as ‘threatened’ in 2017 due to a rebound in their numbers.
The future of managing manatee populations in Florida
What will this new understanding of our aquatic neighbors tell us about how we should manage the species?
Thulman told News 6 he hopes it will encourage policymakers and agencies like Florida Fish and Wildlife (FWC) to ensure manatees' survival in a more realistic way.
“It seems maybe unsupportable in the long term to keep throwing iceberg lettuce into the water, but how that occurs is a really tough question," Thulman said.
“It’s sort of like a dog or a cat followed us home and had a litter of kittens,” Plukhahn adds.
“I think we feel responsible for them now, and we hope this research can actually help conserve manatees.”
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