Form & Function

The Western Fence Lizard is a medium sized lizard that measures from 3.9 inches to 8.4 inches in total length, from snout to tail end (Cossel, 1997). These measurements can vary drastically because these lizards have the ability to lose their tails if they need to distract and escape a predator. Sceloporus occidentalis, like other lizards have quick reactions and fast reflexes. Using all four limbs is their main form of movement and they use it to their advantage whenever possible. These lizards will sprint for several reasons, but mainly to escape their predators and to capture their prey. Their sprint speeds can vary drastically depending on the temperature, which impacts multiple things in the lizard’s life.

Like most reptiles, Western Fence Lizards are dependent on the temperature of its surroundings; warm is the mostUsed with permission suitable temperature for these lizards, making them diurnal organisms (Nafis, 2013). When the temperatures start to get too cold, the lizards become inactive and go into hibernation in crevices, burrows, or under rocks (Nafis, 2013). When the weather is warm enough, these lizards will be found in several sunny and exposed habitats, but will not be found in dense, moist forest or low, flat desserts (Cossel, 1997). This requires them to have camouflage to hide from their predators in the wide open. Cossel describes the coloration of Sceloporus occidentalis as having dorsal ground colorations on their pointed scales that include some shade of gray, brown, and tan that are broken by a series of wavy dark lines or blotches. Cossel also observed that the lizards have the ability to lighten or darken the color to some extent depending on the darkness or lightness of the background. So the lizard has some control of its camouflage and is aware of when it needs to be darker or lighter. This really helps them to blend in when they are basking in the sun on a rock or fence post! These aren’t the only colorations on the lizard; there are more detailed markings on both the male and female lizards, with the males being more enhancing. 

Used with permissionAccording to Cossel, the male S. occidentalis have distinct belly and throat patches that are vividly blue, bordered by black marking. These blue patches are mainly on the males for reproductive purposes, and is one method the males use to show off to the females and get a mate. Along with that they have scattered blue and green scales on their backs, making them “flashy” and attractive to the females. The female and juvenile Western Fence Lizards patches are either absent or less prominent. However, on the posterior limbs of the Western Fence Lizard there is yellowish orange coloration with black lines, these colors help distinguish them from Sagebrush Lizards. This allows for adult females and males to be distinctly different from one another and other species, and makes them easily recognizable.

The Western Fence Lizard is quite tolerant and adaptable to several habitats. Salice and colleagues did an experiment to test just how tolerant these lizards are to inorganic lead, which represents the pollution from the nearby cities by or within their habitat. Salice et al. (2009) dosed the lizards with several levels of lead over a course of two different time periods of fourteen days and sixty days. The results showed that the lizards were tolerant of up to 500 mg/kg/d of lead for fourteen days or 20 mg/kg/d of lead for sixty days. Nonetheless, pollution is the number one cause of declining numbers in their populations, but the population of the Western Fence Lizards is quite stable. As of now their species is classified as not rare and apparently secure, making them a low priority group for worries extinction (Cossel, 1997). Sceloporus occidentalis is an abundant reptile in several areas and easily encountered in the western United States.

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