5) Pleistocene Epoch

The Pleistocene Epoch (2.6 million- 11,700 years ago) is one of the more notable time periods in history. Due to Milankovitch cycles (changes in how the earth rotates around the sun/ tilting orientations), there were many alternating cold periods (Ice ages) and warm periods (interglacial periods). Many freshwater/ terrestrial pleistocene fossils are found mixed in with marine Miocene fossils in Florida rivers and creeks due to the water bodies cutting through the multiple geologic layers.

Mammals that lived in Florida during the Pleistocene

Life was overall very similar to today's animals with a few exotic megafauna on land. The landscape was dominated by herbivores such as horses, llamas, columbian mammoths, huge armadillos, capybara, & tapirs; and teeming with predators such as dire wolves, sabertoothed cats, american lions and cave bears (and smaller more "modern" animals lived here too).

Around 20,000 to 15,000 years ago, humans migrated over the Bering landbridge connecting Asia and North America, and eventually reached Florida, much like how some mammals such as giant ground slothes and armadillos migrated from South America when the Panama canal closed (5 million years ago).

Continents during the Last Ice Age (Around 20,000 years ago)

During the last Ice Age (around 15,000-12,000 years ago?), Florida's landmass was 2 to 3 times larger (extending to the west) due to sea levels lowering (ocean water trapped in glaciers). Historically Florida's terrain was not static, as open oak and pine forests with grassy undercover dominated during warm periods and pines forests thrived during colder climates. No glaciers ever scourging over Florida (why Florida doesn't have very ancient hundreds of millions years old rocks near the surface, as no glaciers were ever here to cut through the newer geological layers)

Fun Facts:

+Carbon dating can be useful for Pleistocene fossils, as the technique can be used for fossils up to 50,000 years old.

+No one is completely sure what killed off most of the large mammals from the Pleistocene. It is most widely believed climate change (perhaps wetter climates during cold periods), mass human hunting on the megafauna, or a combination caused their extinctions.