Earless lizards lack external ear openings, an adaptation to burrowing in the sand, as are the recessed lower jaw and flared upper labial scales.

The greater earless lizard is native to the Chihuahua Desert and other arid and semi-arid regions of Southwestern United States and northern Mexico, where they most often occupy moderately open areas of sparse vegetation with rocks, gravel, and sand.

The trivial name, or specific epithet texanus, is a toponym in reference to the state of Texas, the original location where the specimens used in the lizard's description were collected.

[6] Later, that same year, the species was transferred to the genus Holbrookia in a review by Spencer Fullerton Baird and Charles Frédéric Girard, and subsequent literature used the name H. texana for well-over a century.

[10]: 5 p.  Both combinations, C. texanus and H. texana, were used by various authors during the 1970s, although, despite arguments for the placement of the species in Holbrookia,[11][12] Cophosaurus was in predominant use by the 1980s; later allozymes analyses supported the recognition of the genus.

The colors are most prominent in the Chihuahuan greater earless lizard (C. t. scitulus) and are greatly enhanced and most noticeable in the breeding season in all subspecies.

[2][22] In south-central Tamaulipas, its occurrence becomes increasingly spotty and localized, with records just across the southern state line in eastern San Luis Potosí.

[22][27][24][19] The Sonoran greater earless lizard (C. t. reticulatus) is endemic to northeastern Sonora, Mexico, between 470 – 1300 meters, where, as recently as 2016, it was reportedly known from only eight localities.

[28] The longevity of the greater earless lizard is typically 3 years, but records of individuals surviving five reproductive seasons in the wild have been documented.

A study in Mohave County, Arizona found insects comprised 85% of the diet, including 18.2% Orthoptera (crickets, grasshoppers, locusts), 15.8% Hymenoptera (ants, bees, sawflies, wasps), and 10.1% Lepidoptera (butterflies and moths), 9.2% Diptera (flies), 9.2% Coleoptera (beetles), and 8.4% Hemiptera (true bugs).

[32]: 180–181 p.  Another study conducted in the Mapimí Biosphere Reserve in Durango, Mexico, found the most frequent prey items were spiders, Hymenoptera, Lepidopteran (caterpillars) adult and nymph Orthoptera, beetles, and true bugs.

[32][34] Cophosaurus use a sit-and-wait foraging strategy, often situating themselves on a high vantage point such as a rock, bolder, or fallen limb, in a relatively open space and dashing out to take passing insects.

Competition for food between adults and juveniles, as well as other species of sympatric lizards is at least partially alleviated by resource partitioning, determined by differences in body size and jaw length.

[34][35] The greater earless lizard native to the arid environment of the Chihuahua Desert, extending into western areas of the Tamaulipan mezquital, and the northeastern margins of the Meseta Central matorral, as well as the semi-arid Edwards Plateau and Central Great Plains in Texas, and the Arizona transition zone (between the Sonoran Desert and Arizona Mountains forests) in the west.

[32][34] Limestone ledges and outcrops near streams with boulders and crevices, and dry gulches, arroyos, and canyons with alluvium deposits of silt, sand, gravel, and rocks are often preferred, but it is not strictly limited to these areas.

[37] Plants identified in association with greater earless lizards include honey mesquite (Prosopis glandulosa), creosote bush (Larrea tridentata), ocotillo (Fouquieria splendens), sotol (Dasylirion), lechuguilla (Agave lecheguilla), prickly pear cactus (Opuntia), leatherstem (Jatropha dioica), and candelilla (Euphorbia antisyphilitica).

[40][41] They are predominantly ground-dwelling lizards that often seek a high perch, such as a protruding rock, to survey their area for passing prey and approaching predators.

[17] Males, females, and even hatchlings only five minutes old exhibit territorial displays including head bobbing, pushups, lateral body compression.

[17] The practice of curling the tail over the body while of running also serves a functional purpose as a counter-balance, shifting the center of gravity closer to the force exerted by the lizard's rear legs.