CLASS REPTILIA: REPTIlES
leatherback sea turtle: Dermochelys coriacea
Ever thought, “I wish I didn’t have scales; then I could breathe through my skin!”? If you answered no, I’m guessing you’re not a reptile. Unlike our friends over in classes Chondrichthyes, Osteichthyes, or Amphibia,...
...reptiles couldn’t breathe through their skin if they tried! Instead, they must use only their lungs for respiration. Scales are made up of alpha and beta keratin, which are formed from the epidermis and do not allow the exchange of gases. Reptiles may not have the upper hand when it comes to easy breathing, but they sure do have bragging rights over their circulatory system! Most reptiles have a three-chambered heart like amphibians, but with a partition down the third chamber. This means that even less blood gets mixed in this heart! What about the rest of that “most”? Crocodilians have a four-chambered heart- that’s as many chambers as our hearts have! This heart completely separates the oxygenated and carbon dioxide-filled blood. No mixing blood for the crocodiles! Speaking of blood, reptiles cannot regulate their own body temperature. Basically, if you’re a reptile, don’t go to Antarctica. Bummer, right? Well, not really. While reptiles have to sunbathe if the weather gets too cold and go in the shade if the weather gets too hot, they don’t use all the energy that we do keeping our body temperature at the right degree. Thus, they don’t have to eat three times a day like us. Reptiles reproduce sexually using internal fertilization, unlike many amphibians or fish. Amphibians have to lay their eggs in the water because they will dry out if not, but reptiles use leathery shells to keep moisture in the egg. The egg also provides food, waste disposal, and breathing pores for the embryo’s development. When the baby emerges, it will already look like a small version of the adult in its species. This is called an amniotic egg.
As you can see, above is the leatherback sea turtle. It’s called leatherback because its back feels like, well, leather. As the name suggests, leatherback sea turtles have a more flexible, almost rubbery shell compared to most other sea turtles, who have hard, bony shells. These animals can dive to depths unknown to any other turtle and remain underwater for up to 85 minutes. Even crazier, they have developed amazing adaptations which allow them to regulate their body temperature! If you now want one of these turtles as a pet, they can be found in the Indian, Pacific, and Atlantic Oceans and the Mediterranean Sea. These huge creatures love soft-bodied animals, especially jellyfish. Unfortunately, most leatherbacks don’t get to enjoy a long life because of human activity. Many eggs are taken and turtles caught by fishing lines or hit by boats. They also can die after eating plastic debris, which they mistake for their favorite food (if you’re a plastic bag-user, you should feel guilty). This species has sadly been declared endangered.