A 2003 capture study in southeastern Colorado found that lizards were active at air temperatures of 21 to 42oC (average 30oC) with the greatest number captured between 29 to 31oC.  The study also found that the dominant cover types were grasses (46%) and bare ground (43%).  The remaining cover came from litter (5%), forbs (5%), and shrubs (1%).  Buffalo grass and blue grama were the dominant grasses at every site with sandsage, yucca, and cactus being the dominant shrubs. 

	The diet of the Texas horned lizard consists primarily (85% or more) of harvester ants supplemented with other insects.  Lizards can consume up to 200 ants per day.  During the hotter months, they generally eat in the morning, after the sun has brought up their temperature, and in the evening after sundown.  The 2003 study mentioned above found that during the cooler temperatures in April, May, and September, the lizards were active during the day.  Since harvester ants require seeds for food, they tend to make their mounds in high seed producing areas.  Thus, Texas horned lizards are often found in open patches of less dense vegetation adjacent to the ants mounds.  Invasive red fire ants and Argentine ants are major causes of harvester ant decline in other parts of the Southwest and efforts to control their spread have so far not been very effective. Availability of water may be a limiting factor for one or both of these species, so not introducing external water sources such as irrigation would be a sensible management decision to benefit the harvester ant population.

	According to the Natural Resources Conservation Service, there are 25 ecological sites occurring in Baca County, Colorado. While the ecological site descriptions don't specifically list Texas horned lizard, 13 are mentioned as supporting short-horned lizards (Phrynosoma douglasi).  These are loamy, loamy slopes, clayey, siltstone plains, shallow siltstone, gravel breaks, shale breaks, salt flat, sandy salt flat, salt meadow, Plains swale, saline overflow, and overflow.  Plant communities of interest within these ecological sites are generally flat-lying blue grama and buffalograss sod or bare ground communities which can contain cactus or low, sparse brush.  Average air temperatures in Baca County are also appropriate for Texas horned lizard habitat, with suitable temperatures occurring in June, July, August, and early September.

	In addition to meeting the needs of harvester ants by having areas with relatively high density of grasses and therefore the seed the ants need, the area has a wide variety of vegetation. The vegetation types found in Baca County, from farm ground to blue grama / buffalo grass and continuous bare ground, are good for meeting the needs of Texas horned toads themselves, who require light vegetation to move around near these ant populations and areas that are bare to help them with their temperature regulation through thermal regulation.  

	A mixture of mid to early late seral stages would be appropriate to support harvester ants and thus Texas horned lizards.  The 46/43 split between blue grama/buffalograss sod and bare ground indicate long term continuous grazing. 