New Discoveries point Scientists to Huge Ancient Sea Turtles
by Simone Rogers, age 15
Sea turtles first roamed planet Earth about 250 million years ago. Scientists know this because fossils records indicate sea turtles are from the Jurassic period. Scientists learn more every year about these fascinating ancient creatures. For instance, the skull of a sea turtle found in South Dakota in 1996 is 70 million years old. From this discovery scientists learned that, at one time, sea turtles were twice as big as they are today.
The evolution of sea turtles tells an interesting story. Originally they had four appendages instead of flippers, suggesting they once lived on land. They had hard shells, and their color was different from than. Their necks were longer, and researchers think the ancient turtles were probably meat eaters. About 65 million years ago, at 13 feet 10 length they were the largest sea turtles to ever roam the earth.
Climate change has a major effect on endangered species like sea turtles. A good example is nesting beach temperatures. This can have a special impact on sea turtles. Because these turtles incubate their eggs in the sand, temperature determines the sex of hatchlings. The eggs in the lower cooler part of the nest will become males; the ones in the upper warmer parts become females.
Scientists think there have been more female hatchlings than males, in recent years. This is a threat to the genetic diversity of the species.
In addition, warmer ocean temperatures are affecting sea turtle food resources in and around coral reefs. Scientists are working to protect these fascinating animals. They are moving some eggs to cooler places, just as they are ready to hatch. Scientists also often act as a chaperone during key hatching periods to guide the hatchlings to water and protect them from predators.
Although their survival is threatened by human activity and habitat issues, science is launching new efforts to ensure the future of sea turtles.
[Sources: www.conserveturtles.org; www.seaturtle-world.com]