Marilynne's Wetlands and Other Stuff - 2020
- Thread starter Marilynne
- Start date
Contacted the FWC and here's the response I got back.
Although the leglessness of glass lizards causes them to superficially resemble snakes (the genus’ name Ophisaurus means “snake-lizard”), there are several fairly easily seen differences between snakes and lizards. These include:
- Body proportions. Most of a snake, say ~90%, is body, with the tail occupying just the very last part of the animal. In lizards, including glass lizards, the body is only the first quarter of the animal, the rest being tail. The demarcation between body and tail can be seen at the vent or cloaca on the underside, the single opening through which the animal passes feces, uric acid, musk, and sexual organs.
- Tail. A special attribute of glass lizards, which you witnessed, and how they get their “glass” name, is the ease with which the tail breaks off. There are special break points along the tail such that if grabbed by a predator, the tail breaks off easily and keeps on wriggling while the important part of the lizard (i.e., its head and body) crawl safely away. A new but shorter tail will eventually grow in replacement. Other lizards can grow back their tail, but don’t have the special break points of glass lizards. A snake’s (relatively short) tail doesn’t “come off”; if it is cut or bitten off it won’t grow back.
- Skull and jaws. Everything about a snake is engineered for flexibility and stretching. A snake’s jaws are loosely attached to allow the snake to swallow something several times larger than its head. Having no limbs to grip prey and take bites, whatever a snake eats (and it only eats other animals), it has to eat whole. A lizard’s head is more solid and its jaws only open like ours so it can eat only relatively small food items. Lizards with legs to support them can tear off pieces of food, as with plant eaters like iguanas.
- Ear opening. Snakes don’t have external ear openings, but lizards do. I can see the glass lizard’s ear opening just past the third band behind the eye.
- Eyelids. Snakes have a fixed scale over each eye that they shed with the rest of the skin when they shed; a snake with cloudy bluish eyes is getting ready to shed. Most lizards, including glass lizards, have moveable eyelids, so you’ll see them blink.
- Scales and body flexibility. The scales of snakes are fixed on a very stretchy skin; the skin can stretch greatly to accommodate swallowing and digesting large food items. Terrestrial snakes have large, overlapping belly scales called scutes that are attached to muscles that are attached to the many pairs of ribs. Moving the muscles in a wave fashion enables snakes to slither or glide smoothly on their big belly scales. In contrast, lizards have small scales all over their body; the small scales on the belly of a glass lizard don’t contribute much to its locomotion. A glass lizard typically thrashes awkwardly when put on a smooth surface (very un-snakelike); it moves much more smoothly when it can use vegetation to give it purchase.
It's already rained twice here and for most of the week its looked like Cleveland.
As usual you got some nice shots this AM.