Wednesday, July 6, 2011

A blue-belly's blue belly

The western fence lizard (Sceloporus occidentalis) lives in almost every part of California and Nevada and in certain areas of the neighboring states. Males show bright blue patches or lines along the sides of the body [1-3], which are best seen when the lizard turns around—what he never does. While I was watching a western fence lizard in the upper Hunter Creek area west of Reno in Nevada, a friendly hiker came along, carefully picked up the lizard and turned him around: the above picture shows the blue belly and his yellow-orange limbs. The picture below shows the typical angle of view, which we have, when encountering lizards. The skin with coarse, spiny scales of this male lizard, exhibiting patterns of light and dark brown triangular polyominoes on a grayish white background, can be seen.

The western fence lizard is normally not found in the desert, maybe in desert canyons. Its preferred habitats include the ground, rocks and lower parts of coastal sage brush, chaparral and woodlands—from the Pacific coast (a disjunct population occurs on Isla de Cedros off of  Baja California [2]) to high elevations below 9,000 feet like the Lake Tahoe area. Its diet includes spiders, scorpions, centipedes and insects such as caterpilllars, beetles, ticks, crickets, flies and ants as well as, but rarely, other lizards [4]. My favorite part about their feeding behavior is the tick diet, which reduces our risk of getting Lyme disease: ticks in regions inhabited by the western fence lizards carry Lyme disease 45 percent less frequently than ticks in other regions [5].

References and more to explore
[1]  San Diego Natural History Museum: Sceloporus occidentalis, Western Fence Lizard [].
[2] I. Lindsey: Western Fence Lizard, Sceloporus occidentalis [].
[3] Peter Alden and Fred Heath: Field Guide to California. National Audubon Society, Chanticleer Press, 1998; page 257. 
[4] Mary Sharp: Western Fence Lizard's Diet []. 
[5] Laura Hautala: Watching for Blue Bellies. Bay Nature June 2008 [].

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