by Chuck Rigby
Lizards are a very common animal in the Illinois Valley area. They are also very useful in helping to control insects and spiders. They also serve as a handy food source for hawks, snakes and predatory mammals. The lizards main protection is to blend in with their surroundings and then move very quickly to avoid capture.
They have another defense mechanism which is familiar to most people, that is their ability to drop their tails. The tail, when dropped, will jerk and twist to distract the predator while the lizard may escape in the confusion. This process is more complicated than it seems. The muscles in the detached tail need to have a stimulus from the nervous system even though it is severed. Another requirement is that the blood vessels need to close off quickly in the lizard to prevent much blood loss. The tail is dropped by contractions of the lizard’s muscles and not by the action of the predator and can only occur along a fracture line in the middle of a vertebral bone and not between bones. When the new tail grows it usually has cartilage rather than bone and it is often a slightly different color. All this action can only occur at specific points along the tail rather than at any random spot.
Experts list five species of lizards in Josephine County but most of us are only familiar with three: alligator lizards, western skinks, and western fence lizards or blue-bellies. The largest and most aggressive are the alligators which can have a body length of 7inches and another 14 inches of tail, if they have never dropped their tail. Actually there are two species: northern alligator lizards and southern alligator lizards. The northern is more gray in color with dark cross bands on its back, while the southern is a lighter brown color with lighter bands and are usually a little larger. Both are found in our area but they are hard to distinguish unless both are present at the same time.
Western skinks have a much slicker appearance than the other lizards and usually harder to capture because of their speed. They also lose their tails very easily and it is the tail which is most noticeable. The immature skinks have a bright blue tail and more pronounced lines running the length of the body. Fully mature skinks will have a brown tail and very faint lines. Skinks generally are found in moist areas while the other lizards will be in drier sections.
The common name of “blue-belly” is often used for the 4-inch species of lizard in the region.
Officially it is called western fence lizard because often it is seen on fence posts where it can warm itself in the sun. They also do “pushups”, while on posts or on rocks, to control their body temperature. Only the males have the bright blue areas on the underside of the head and body. These lizards can also change their body color slightly by becoming lighter or darker in order to blend in better with its surroundings. The fence lizards also have spiny scales that stick up along their back.
They are often mistaken for sagebrush lizards which is the 5-inch species of the valley. The sagebrush lizard is smooth, like the alligator lizard, but it has a blue belly. The blue color on the belly does not extend up in the head area and also it lacks yellow sections on the underside of the legs, which the fence lizard has. Sagebrush lizards are usually higher in the mountains. The two species are easily thought to be the same. Even if the names get confusing, lizards are an interesting group and are much easier for people to tolerate than their close relatives the snakes. They are a vital part of the ecosystem of the Illinois Valley.