San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Photo of California Collared Lizard, on a rock at San Ignacio microwave station, Baja California Sur, by Bradford Hollingsworth.

Crotaphytus vestigium
Baja California Collared Lizard

CROTAPHYTIDAE

Crotaphytus is from the Greek krotaphos, meaning the side of the head or temple region, and phyton, a creature or animal. It refers to the large jaw musculature of these carnivorous lizards.  Vestigium, from the Latin, meaning a trace, refers to their reduced collars. In Spanish, the Baja California Collared Lizard is called escorpión, a general name for most lizards. An older scientific name for this species was Crotalus insularis vestigium.

Description

The Baja California Collared Lizard is a relatively large lizard with a robust head, strong jaw musculature, short snout, and laterally compressed tail.  This species is sexually dimorphic with large males -- measuring about 5 inches (125 mm) snout-vent length, and small females -- about 4 inches (98 mm) snout-vent length.

This species is tan or light brown with two widely separated black collars. Slender, white bars cross the back, and a white to off-white dorsal stripe runs down the tail. The black inguinal patches located along in front of the hindlimbs and the black neck collars serve to attract females and warn off other males.

Range and Habitat

The Baja California Collared Lizard ranges from the San Jacinto Mountains in Riverside County, southward to San José de Comondú, Baja California.  In the northern part of its range, it's found along the eastern desert slopes of the peninsular mountains; south of the Sierra San Pedro Mártir, it inhabits both sides of the mountains.

This species is always found in sparsely vegetated rocky areas of hillsides, canyons, and lava flows.

Natural History

Photo of ventral side of very relaxed California Collared Lizard in hand, San Ignacio, Baja California Sur, by Bradford Hollingsworth.
Photo of ventral side of very relaxed California Collared Lizard in hand, San Ignacio, Baja California Sur, by Bradford Hollingsworth.
To photograph the coloration of the underside of the lizard, this photo was taken by gently rubbing the lizard's belly, a phenonema that puts the lizard into a relaxed state which allows it to be turned over.

Behavior: The Baja California Collared Lizard is often seen basking on small rocks during the hottest periods of the day.  An agile hunter, it can run bipedally, jumping from rock to rock with each step, using its tail as a counterbalance. Because the tail is used in running, this lizard can't afford to lose its tail as many other lizards do, and therefore lacks caudal autonomy. Instead, it's able to lose the skin along the last 20 percent of its tail.  If a predator grabs a Baja California Collared Lizard by its tail, the skin comes off, and the lizard can escape.  Interestingly, it also coils its tail up when hiding under rocks so it doesn't stick out.

Prey and Predators: Like all members of the family, the Baja California Collared Lizard is saurophagous, that is, it preys on small lizards.  Its large jaw and and short snout work well to quickly capture small lizards.

Breeding: The male Baja California Collared Lizard is larger than the female, and throughout the year displays color pattern differences.  The black inguinal and axillary patches located along the sides of the body in front of the hindlimbs and in back of the forelimbs, and the black neck collars serve to attract females and warn off other males.  Its laterally compressed tail presumably makes the lizard look larger when seen from the side. In general, females are less vividly marked and display bright gravid coloration after breeding occurs -- which may protect them from being eaten by the fierce males of their own species.

Conservation Status

There has been no proposed conservation plans.

Suggested Reading

McGuire, J. A.  1996.  Phylogenetic systematics of Crotaphytid Lizards (Reptilia: Iguania: Crotaphytidae). Bulletin of the Carnegie Museum of Natural History 32:1-142.


Text and photo contributed by Bradford Hollingsworth.

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