NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/683373
JUNE 2016 • NEBRASKAland 15 Amphibian or Reptile? By Dan Fogell As a herpetologist I get a lot of crazy calls about a group of animals most people know very little about. One such call was about bright blue salamanders someone had in their yard. Bright blue salamanders. We don't have any bright blue salamanders in Nebraska, so this was going to be fun. I asked for more details and got blue with a little green, but it was hard to see because they move so fast through the sand. But they were always out there in the middle of the day. None of this screamed salamander to me, but by now I knew what they were. I explained they were not salamanders, which are amphibians, but rather they were lizards, which are reptiles. Prairie racerunners to be precise. Males turn a bright blue in spring to impress the ladies, they are extremely fast, and they prefer sandy environments. The caller responded with "Well what's the difference?" Good question. The science of herpetology involves the study of amphibians and reptiles … two very different groups of animals. Why they are linked together is beyond me and makes very little sense, other than they are both ectothermic tetrapods. Ecto what? Ectothermic, meaning they gain heat from an external source – like the sun, and tetrapod, meaning they have four legs (or at least they DID at one point in their evolutionary history). Other than that, they have very little in common. Amphibians and reptiles haven't shared a common ancestor for more than 300 million years. The amphibians include frogs, toads and salamanders. Their name is from two Greek words meaning "double life" (amphi = both, bios = life), a description of their life history. Their ties to water make them both anatomically and physiologically different than reptiles. They have scale- less, usually moist, and very porous skin. Some breathe using lungs, but all of them breathe through their skin, and some actually have gills … like fish. And while they may be adapted to terrestrial life they return to the water to reproduce. Most lay eggs similar to fish eggs with a jelly-like coating around the embryo, which hatches into an aquatic, gilled larva. Larvae metamorphose to become land- dwelling adults. Due to their reduced number of neck vertebrae, amphibians have a relatively immobile skull. Reptiles, from the Latin word reptilis meaning creeping or crawling, include snakes, lizards, crocodilians, and turtles. Compared to amphibians they have scaly, dry skin that is somewhat impervious. All reptiles breathe using lungs, and reptiles either lay leathery, shelled eggs on land or give live birth. Their shelled egg – called an amniotic egg – keeps the embryo in an aquatic environment without having to be in the water, thus completely severing their ties to water. Even reptiles that are somewhat "amphibious" (such as turtles) return to land to lay eggs. Newly born reptiles are not larval and require no metamorphosis, but instead are small versions of the adults. Numerous neck vertebrae give reptiles a highly movable skull making them better hunters. So while the tendency is still to lump "cold-blooded terrestrial vertebrates" together into a single group of animals called herpetofauna, the truth is that amphibians and reptiles are much more different from each other than they are similar. ■ Reptiles, like this prairie lizard, have scaly, dry skin and either lay leathery, shelled eggs on land or give live birth. Amphibians, like this barred tiger salamander, are tied to water and have scaleless, usually moist and porous, skin.