Excerpts from Jim Conrad's
Naturalist Newsletter


from the September 16, 2012 Newsletter issued from the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA

Coastal Plain Toads aren't the only critters who like the cement floor of the community's park shelter. In early mornings you're likely to see slender, eight-inch-long (20cm) lizards starkly patterned with narrow, alternating pale and dark lines quietly resting on the cement floor, basking in the warm sunlight. You can see one doing just that above. A closer look at the front end is afforded below.

Texas Spotted Whiptail, CNEMIDOPHORUS GULARIS, front view

On the farm in western Kentucky I grew up with a very similar lizard, the Six-lined Racerunner, Cnemidophorus sexlineatus, common in the US Southeast and south-central states. However, this is a different species, the most conspicuous difference being that the Six-lined Racerunner's black lines are solid black, while you can barely see that on our cement floor one the black lines are broken with indistinct pale spots. Also, Six-lined Racerunners tend to have brownish tails while the tail of ours is pinkish.

Our cement-floor lizard is the Texas Spotted Whiptail, CNEMIDOPHORUS GULARIS, endemic to Texas and small parts of adjacent Oklahoma, New Mexico and Mexico. Being in the same genus as the Southeast's Six-lined Racerunner, you can see that the two species are closely related.

As you might guess, our whiptail eats grasshoppers, spiders, termites and the like. He's a very fast mover who when disturbed runs a short distance, stops and checks to see if he's being chased, then either nonchalantly begins walking around or continues running. He's active during the day. As with all members of the Whiptail and Racerunner Family, the Teiidae, prey is located by sight, smell and sometimes by taste, the latter by means of a long, protrusible, deeply-forked tongue. All "teiids," as the pros call members of the family, are egg-layers.