It was once inconceivable that humans could have been in Florida at the same time as mammoths and mastodons. Those large beasts, and a couple dozen other large mammals, went extinct just under 13,000 years ago. The oldest archeological sites in North America were 13,000 years old, belonging to the Clovis culture. The dates lined up with evidence of an ice-free corridor having thawed as the world warmed at the end of the last ice age. Florida is the furthest state from Alaska, where people crossed from Asia. It wasn't all that long ago that most archeologists didn't think that Florida would have old prehistoric sites.
All throughout the twentieth century, though, recreational divers kept finding mammoth and mastodon bones alongside stone tools and projectile points. Archeologists like James Dunbar and Michael Faught were intrigued, and started adapting archeological techniques to submerged settings. Dunbar's excavations of the Page-Ladson site on the Aucilla River were especially eye-raising. They found the bones of several extinct mammals, and a mastodon tusk that appeared to have human-made marks on it. They also found a few flakes from human-made tools. When they dated the site they obtained a date of 14,500 years old.
The date was too early, and in the wrong place. And it was excavated under water. The Page-Ladson date wasn't taken seriously, and work on it and other submerged Florida sites stopped in the early 2000s.
A new generation of archeologists returned to Page-Ladson in 2012. When they confirmed the dates, it sparked a renewed interest in Florida waters. It turns out that Florida is a prehistory hotspot, and its waters preserve fossils and artifacts better than terrestrial sites.
Not only are archeologists finding evidence of the First Floridians, they're learning about the world they inhabited. A couple dozen large herbivores went extinct or left Florida by the end of the Pleistocene epoch, and what we know of their diets lets us know about Florida's landscape, as does pollen and charcoal in the sediment record.
Sea level was lower in the Pleistocene, as was the water table. Humans had to find water on a dry landscape, in a Florida with almost twice as much landmass as it has today.
It was a much different place than it is today, and it was constantly changing, taking thousands of years to become something more familiar to modern Floridians. Indigenous people had to adapt to these changes, adaptations that showed up in sites as technology and culture changed along with the land.
In Finding the First Floridians, we explore this ever-changing world, and learn about the techniques used to learn about it.
You can take a deeper dive into this subject on the WFSU Ecology Blog: https://blog.wfsu.org/blog-coastal-health/documentaries/finding-the-first-floridians-underwater-archeologists-uncover-floridas-prehistory/