It’s Sea Turtle Day! Not to be confused with World Turtle Day, which celebrates all shelled reptiles, this day is solely about those turtles that exist almost entirely in an aquatic environment. Sea turtles are marine reptiles that spend nearly all their time in the sea, only coming on shore to lay their eggs. Living in this habitat has led them to evolve specialized skills and traits to adapt to their watery surroundings.
Unlike tortoises, which have thick legs and claws, or terrapins, which have webbed and clawed feet, sea turtles have evolved their legs into paddle-shaped flippers that help to propel them efficiently through the water. Their shells are typically smoother and more streamlined than tortoises or terrapins, which helps them travel more speedily through the ocean, but also means they can’t retract their heads or legs into their bodies like other turtles. Sea turtles are able to slow their breathing and heart rate, which allows them to dive underwater for long periods of time without needing to surface for air. They also have a special gland that removes the excess salt that accumulates in their body from their marine environment.
|Green Sea Turtle||Loggerhead Sea Turtle||Kemp's Ridley Sea Turtle|
There are currently seven living species of sea turtle: the loggerhead, the green, the hawksbill, the olive ridley, the Kemp’s ridley, the flatback, and the leatherback. All can be found in the family Cheloniidae except for the leatherback, which is the only living member of the family Dermochelyidae. The turtles of the first family have bony shells of fused plates, similar to most other turtle types. The leatherback, however, is unique in that its shell is covered in leathery, oily skin instead of bony plates. Though it lacks teeth like all other turtles, the leatherback has specialized spines in its throat to keep prey from escaping and guide it downward toward the turtle’s stomach.
|Leatherback Sea Turtle||Loggerhead Sea Turtle|
Sea turtles have been around, largely unchanged, for over 100million years. However, many sea turtles today are threatened with extinction to some degree. Loggerheads, leatherbacks and olive ridleys are considered vulnerable, while the green turtle is endangered. The hawksbill and Kemp’s ridley turtles are both critically endangered. These turtles can get tangled in fishing nets, and are also hunted for their meat and eggs. They are also vulnerable to oil spills and other marine environmental disasters. Plastic waste also harms sea turtles, who often become tangled in soda can rings or may mistake a floating plastic bag for a tasty jellyfish snack.
|Sea Turtle Hatchling||Kemp's Ridley Sea Turtle Hatchling|
Sea turtles are affected by human activity from the moment they are born, and sometimes even before. Sea turtles lay their eggs on land, burying them in beach sand. Climate change affects sand temperature, which can affect whether hatchlings are male or female, throwing off the ratio and making it difficult to find mates. Light pollution on beaches can also make it difficult for baby turtles to navigate to the sea upon hatching. When sea turtles hatch, they must quickly make it to the ocean before they are caught by predators. Too many lights near a beach can distract baby turtles and disorient them, making them easier prey and leading them further away from the sea. If you’re in an area where sea turtles are known to nest, make sure you do not use floodlights, high intensity flashlights or flash photography, as these can damage turtles’ eyes and startle nesting mothers, causing them to abandon their attempts to lay eggs.
Conservation efforts both globally and locally are devoted to protecting our sea turtles. You can help by doing something as simple as cutting apart your soda rings before throwing them away, or re-using and recycling your plastic bags so they don’t end up in the ocean. An even better choice is to opt for paper bags, or bring your own bag to the grocery store. It may seem like a drop in the bucket, but every little bit helps to save these wonderful sea creatures!
Bernie’s Bonus Fun Fact: Some sea turtles have recently been shown to exhibit biofluorescence, meaning they can reflect certain light that shines upon them as a different, often brightly glowing color. Hawksbill turtles are known to glow green and red when a blue light is shone on them.