Pliocene Epoch

5 million to 2 million years ago

The formation of a land bridge across Panama in Central America about 3 million years ago was a major biotic event. Both North and South America had been previously isolated for millions of years. Each had evolved its own unique flora and fauna.

Contact between North and South America allowed for the overland dispersal of organisms between the two continents. Mammals living in North America traveled to South America, and South American mammals moved north. The closure of the seaway between North and South America apparently resulted in extinctions of many marine organisms. However, newly formed habitats also promoted the evolution of many new species.

Video produced, directed and filmed for the Florida Museum of Natural History by Wes C. Skiles/Karst Productions, Inc.


Dramatic changes are occurring on Earth. The great mountain ranges are uplifting further into the sky. Seasonal extremes in weather signal the coming of the Ice Ages.

We have entered the Pliocene Epoch occurring between five and two million years ago. Mysterious new residents begin to appear in Florida. Titanus, the flightless Terror bird, reached heights of nine feet and was certainly one of the most dominant carnivores to ever reside in Florida. But where did it come from? Scientists believed it walked here from South America. This is the time of the Great American Biotic Interchange and its impact would forever alter life in Florida both on land and in the sea.

The interchange occurred with the emergence of the Isthmus of Panama in Central America. This caused the closing of the seaway for marine life and created a land bridge allowing the migration of plants and animals between the Americas. The giant armadillo and the even larger Glyptodont were among the many creatures that migrated north and found their way to Florida. During the Pliocene, horses similar to today’s Equus first appear. Elephant-like mastodons and 15-foot tall giant ground sloths are the largest plant-eating herbivores in Florida’s ancient forest and grasslands.

In southwest Florida, scientists from the Florida Museum of Natural History have discovered an ideal location to study the shallow coastal environment of the Pliocene. These vast shell beds contain amazingly well preserved fossils that reveal both the diversity and uniqueness of this important time in Florida’s history.

After making the marine trek from South America, ancient manatees of the modern day genus Trichechus first appeared in the Florida fossil record during the Pliocene. Marine fish and birds, like the cormorant, were killed by red tides much like those seen off the Gulf Coast today. Although the Pliocene in Florida represented a time in which many extinctions occurred, it also saw the evolution of many new species and sets the stage for the arrival of one of the planet’s most dangerous predators.