Reticulate collared lizard (Crotaphytus reticulatus)

Spanish: Lagartija De Collar Reticulada
GenusCrotaphytus (1)
SizeTotal length: 20 - 43 cm (2)
Head-body length: 13.7 cm (2)
Hatchling length: 9-10 cm (2)

The reticulate collared lizard is classified as Vulnerable (VU) on the IUCN Red List (1).

A large, agile lizard usually seen basking on boulders (2), the reticulate collared lizard (Crotaphytus reticulatus) has a beautiful, regular pattern of light scales covering its back (2) (3). The arrangement of these scales gives it the common name ‘reticulate’, which means net-like (2). Species in the genus Crotaphytus are known as ‘collared’ lizards due to black markings found around the neck. However, the male reticulate collared lizard has black spots instead of a complete collar and the female either has faint markings or none at all (3) (4).

Like other members of Crotaphytus, the reticulate collared lizard has a large head and a slender neck. It has a fat body and sturdy limbs, with the back legs being twice as long as the front legs (3). The tail is slightly flattened from side to side, and it can measure over twice the reticulate collared lizard’s head-body length (3) (5).

Generally a grey to reddish-brown, the reticulate collared lizard also has a series of distinctive black spots on its back. The spots are commonly arranged in lines and neighbouring spots are sometimes merged together. In warm weather conditions, the net-like pattern on the reticulate collared lizard’s back appears bright and well-defined; however, when the lizard is chilled the pattern becomes almost indistinguishable (2) (3). The net-like markings continue down the legs, but unlike the back, the limbs and tail do not have any black spots. The underside of the reticulate collared lizard is creamy and has no markings (3).

The adult male reticulate collared lizard is larger than the female (6), but both have a similar colouration (3). During the mating season the sex differences become more noticeable, as the male reticulate collared lizard’s chest and front legs become bright yellow. The female may become pinkish and develop red bars between the rows of black spots (2) (5) (6).

Like the adult lizard, the reticulate collared lizard hatchling is greyish, but it has yellow crossbands between the black spots on its back (2).

The reticulate collared lizard has a restricted range, being found only in southern Texas and northern Mexico in the lower Rio Grande Valley (1) (6).

The reticulate collared lizard lives among vegetation and shrubs in areas that are gravelly, rocky or have sandy soils (1), and can also be found in flatland habitats where there are no rocks (6).

It prefers areas with a warm climate, dry soil and shrubs to provide shelter and camouflage (1). In cold conditions, the reticulate collared lizard seeks out small burrows sealed with dirt beneath rocks (3).

Like other reptiles, the reticulate collared lizard is dependent on the environment to regulate its body temperature, and it can usually be spotted basking in full sun on rocks. This basking behaviour may also have a social function, helping the reticulate collared lizard to ambush its prey. The adult and young reticulate collard lizards feed in the morning and evening to avoid the midday heat (6).

Arthropods, such as spiders and grasshoppers, form the majority of the reticulate collared lizard’s diet. It is a skilful predator and an opportunistic forager, with its varied diet known to include small reptiles and mammals (3) (5). This lizard also consumes plant matter, with a preference for Lycium fruits (5). Some Crotaphytus lizardsare able to walk on the strong hind legs, by lifting up onto the limbs at roughly a 45 degree angle. This increases the lizard’s running speed, helping it to capture prey and retreat from predators (7).

The reticulate collared lizard’s social interactions are not fully understood, although it is thought that some movements are purely for display purposes (6). The male is territorial and tends to be the most defensive of the sexes, using head-bobbing and push up displays to keep unwanted individuals out of its territory (7). When startled, the reticulate collared lizard runs to the safety of surrounding shrubs and remains motionless until the threat has gone (1). If it cannot retreat, the lizard defends itself by arching its back, opening its mouth, and biting fiercely (3).

Little is known about the reticulate collared lizard’s breeding biology, but it is thought that it mates between April and May. The female lays 8 to 10 eggs underground or underneath rocks, and these hatch 60 to 90 days later (1) (2) (5).

The most significant threat to the reticulate collared lizard is habitat degradation and destruction. Land is cleared for agriculture and grazing, and non-native grasses are cultivated to provide food for livestock. The introduced grasses can spread and interfere with the lizard’s natural habitat. Pit mining and housing developments also threaten the reticulate collared lizard (1).

The main conservation requirement is to protect the reticulate collared lizard’s habitat from further degradation (1). Research into the rare reticulate collared lizard’s distribution and abundance, as well as monitoring its population trends, would help to create future conservation strategies (5).

More information on the reticulate collared lizard:

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  1. IUCN Red List (August, 2011)
  2. Conant, R. and Collins, J.T. (1998) A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Company, New York.
  3. Smith, H.M. (1946) Handbook of Lizards: Lizards of the United States and of Canada. Comstock Publishing Company, Inc., AND Cornell University Press, Ithaca, New York..
  4. Bartlett, R.D. and Bartlett, P. (20089 Lizard Care from A to Z: From Anoles to Zonosaurs. Barron’s Eduational Series, Inc., New York.
  5. NatureServe Explorer - Reticulate collared lizard (August, 2011)
  6. Husak, J.F. and Ackland, E.N. (2003) Foraging mode of the reticulate collared lizard, Crotaphytus reticulatus. The Southwestern Naturalist, 48(2): 282-286.
  7. ArizonaSonora Desert Museum- Reticulate collared lizard (August, 2011)