Identification
Western fence lizards measure 5.7-8.9 cm (snout-vent length) and a total length of about 21 cm. They are brown to black in color (the brown may be sandy or greenish) and have black stripes on their back, but their most distinguishing characteristic is their bright blue belly. The ventral sides of the limbs are yellow. These lizards also have blue patches on their throats. This bright coloration is faint or absent in both females and juveniles. The scales of S. occidentalis are sharply keeled, and between the interparietal and rear of thighs, there are 35-57 scales.
Many other lizards have similar bright blue coloring. The eastern fence lizard, S. undulatus, instead of having one large patch on its throat, has two small patches. The sagebrush lizard, S. graciosus, lacks yellow limbs and has smaller dorsal scales. S. occidentalis also resembles the side-blotched lizard, Uta stansburiana. However, the axilla of U. stansburiana usually has a black spot behind it and it has a complete gular fold.
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