C. collaris exhibit a wide range of physical characteristics, particularly in coloration and spotting patterns, and this phenotypic variability may be attributed to a combination of differences in population, social organizations, or habitat.

Male dorsal and head color tend to range from green to tan and yellow to orange respectively, while females, overall, possess more muted body pigmentations, varying from brown to gray.

[7] Consequently, juvenile collared lizards lose this sharp cross-band pattern, and their features drastically change to resemble those of either adult males or females.

Used as a weapon during male combat, the head dimensions play a key role in determining dominance, territoriality, fitness, as well as mating success.

Individuals occupy a range of different habitats from rocky desert landscapes to grasslands, but they often prefer to inhabit mountainous regions with high environmental temperatures for optimal thermoregulation.

[9] In addition, the hilly topography allows these keen and highly alert lizards to stay hidden between rocks, despite their flamboyant features, and look out for potential predators or territory intruders from the top of elevated platforms.

They feed on a variety of large insects, including crickets, grasshoppers, spiders, moths, beetles, and cicadas, along with other small lizards and even snakes.

[11] From an evolutionary standpoint, these sexual differences in diet may act to reduce intra-species competition for resources, whereby females and males do not need to fight for the same type of food.

[citation needed] Collared lizards are diurnal;[12] they are active during the day, and spend most of their time basking on top of elevated rocks or boulders.

The collared lizard in the wild has been the subject of a number of studies of sexual selection; in captivity if two males are placed in the same cage they will fight to the death.

[13] In an effort to monopolize as many female mates as they can, male C. collaris viciously defend their exclusive territories through aggression, patrolling activities, and displays.

However, when agonistic interactions between male rivals escalate to violent fights, both lizards must expend substantial amounts of energy and risk getting seriously injured.

[14] This cost-benefit strategy demonstrates the complex social behaviors and decision making processes exhibited by the male collared lizards.

Though lizards are considered mature and may breed following their first hibernation, those that are two years and older exhibit greater reproductive success due to their larger size.

Subsequently, mature females, typically two years and older, produce their first clutches and lay them in a burrow or under a rock about two weeks after copulation.

Consequently, successful males may, more often than not, possess vibrant body coloration and patterns and may be bigger in size, specifically having larger head proportions.

[18] During courtship rituals, a male or a female lizard approaches the opposite sex within 1 body length and subsequently engages in various behavioral patterns, which include either individual superimposing its limbs, torso, or tail over its partner, mounting the dorsum of the other lizard, males nudging females with their snouts or grasping them with their jaws, and mutual displays.