Did you know that Sea Turtles are the oldest living creatures on earth, dating back more than 110 million years to the Cretaceous period? The very first sea turtle known as the Archelon, had flippers that spanned nearly 17 feet, its head was more than 2 feet wide, and it weighed an estimated 5000 lbs! Turtles themselves, have existed since the Triassic Period, 210 million years ago, and the marine adapted turtles that we know of today appeared 10-50 million years later during the Jurassic period.

The evolution of sea turtles began with animals that could only swim in shallow waters as their limbs had not yet modified into flippers like those of modern day sea turtles. Of the estimated 80+ species of sea turtles that evolved during the Cretaceous period, only 7 have survived and still swim in the oceans all over the world, excluding the polar waters. These species are commonly known as: Loggerhead, Green, Hawksbill, Kemp's Ridley, Olive Ridley, Leatherback and the Australian Flat Back. Out of these 7 species, there are no living species from the Archelon or Protostega families, the Leatherback is a direct decendant of the Dermochelyidae family but has some characteristics of the Archelon, and the remaining 6 species are members of the Cheloniidae family.

So just how did sea turtles survive when the dinosaur's could not? Approximately 66 million years ago during the Cretaceous period, a meteor slammed into the earth and wiped out 3/4's of the plant and animal species on earth, while the marine environment only suffered a 10-22% loss. Scientists believe that mainly due to their slow metabolism and aquatic lifestyle, sea turtles and most amphibians were able to survive on sparse resources afterwards. Furthermore, because these animals could go into a sort of animated suspension, they were able to wait out the lack of sun, food and oxygenated water, the extreme cold and the harsh conditions for a few months until the earth started to settle down and the sun returned.

With all that sea turtles have endured during the past 110 million years, its just so sad to think that they are now threatened and/or endangered creatures because of harvesting and fishing from humans. Here in the Florida Keys, sea turtles were a necessary food source to it's earliest inhabitants back in the 1800's. However, turtles became a delicacy, their shells were used for making combs and jewelry, eggs were harvested from nests for food as well and leatherbacks were harvested for their leathery shells. Two hundred years of harvesting turtles world wide finally took its toll on the population.

All species of sea turtle protection began here in the US in the 1970's. Today, Green turtles are the only species that is protected world wide. While many countries have also joined the effort to protect these amazing animals, 42 others have not and do continue to fish and harvest sea turtles, particularly Hawksbills (for their beautiful shells) including Japan, Palau and Grenada.

Watch for next month's newsletter: Basic Sea Turtle Anatomy