Zygorhiza Skull and Jaws

These skull and jaw fossils are from a Zygorhiza, a toothed whale that swam over a submerged Florida peninsula millions of years ago. Zygorhizas grew up to 20-feet long and weighed upwards of 2,000 pounds.

Courtesy of the Florida Museum of Natural History

During the Eocene Epoch (lasting 55 to 35 million years ago), Florida–geologically speaking–existed, but the warm global temperatures of the time led to high ocean levels and a submerged Florida peninsula. It was not until the following cooler epoch, known as the Oligocene (35-24 million years ago), that the ocean levels dropped and parts of Florida were exposed. Life in these ancient seas was no picnic for Zygorhiza. Another toothy whale named Basilosauras, who grew to nearly 60-feet long, and gigantic sharks hunted Zygorhizas.

Three Fast Florida Facts

  1. During the warm Eocene Epoch, the South and North Poles sometimes had zero ice or snow cover.
  2. The oldest “surface deposit” fossils paleontologists have found in Florida are aquatic ones from the Eocene. In other words, Florida’s fossil record begins in the Eocene.
  3. The first humans arrived in Florida around 12,000 years ago, during the last ice age.