59 



tigris were marked and 23 recaptured a total of 8^^ times. One individ- 

 ual recaptured 17 times had a home range of .53 acres based on the out- 

 er polygon method. It was noted that tigris makes a low clicking sound 

 when handled. 



158. — . 1960. Supplementary notes on the herpetofauna of the Stock- 

 ton Plateau. TEXAS JOURNAL OF SCIENCE 12(3/if): 228-231. 



Cnemidophorus gularis and _C. inornatus , which occur in the cedar- 

 savannah association on mesa tops, were virtually wiped out by a 10- 

 year drought while _C. tesselatus went from virtually absent to quite 

 abundant. 



159. — . 1961a. Observations of the activities of small animals 

 (Reptilia and Mammalia) on a quadrat in southwest Texas. AMERICAN 

 MIDLAND NATURALIST 65(1): 127-138. 



Drift-fence trapping was done for 5 weeks beginning in June 1 mi. 

 E. of Alpine, Brewster County. The vegetation of the quadrat, located 

 in the short-grass—mesquite association at ^600 feet, is described. 

 Weather during the study period is described. ^7 female and 32 male 

 Cnemidophorus sacki (= exsanguis + gularis ) were marked and released. 

 51 lizards were recaptured at least once for a total of 156 recaptures. 

 The average home range was .34 (.25-.43) acres; lizards were apparently 

 not territorial. A modified Lincoln Index gave a density estimate of 

 20-25 resident lizards per acre. One lizard was eaten by the snake 

 Hypsiglena torquata . Foraging behavior is described; lizards were ob- 

 served to feed upon scorpions, grasshoppers, termites, candleflies, le- 

 pidopteran larvae, and ant lions. Lizards emit an audible squeak when 

 picked up. 



160. — . 1961b. Competitive relations in lizard populations. _in 

 VERTEBRATE SPECIATION, Blair, W. F., editor. University of Texas 

 Press, Austin, pp. 460-489. 



Four species of Cnemidophorus in Trans-Pecos Texas (inornatus , 

 sacki (= exsanguis + gularis) , tesselatus and tigris ) appear to present 

 an example of competition in the absence of an advantage. They occur 

 sympatrically within this region, although all 4 species are seldom 

 found at any one locality, and rarely do more than 2 species occur in 

 equal concentrations. Furthermore, no two species appear to occupy the 

 same ecological associations in the same areas, although all 4 species 

 do appear to occupy the same ecological niche. The diets of all 4 spe- 

 cies are similar and have the same staple food items. There is some 

 active intraspecific but no active interspecific competition. Foraging 

 abilities appear to be equal or complementary, and activity periods and 



