Callisaurus draconoides

Geographic Range

Zebra-tailed lizards are native to the Nearctic region, occurring throughout the deserts of the southwestern United States and northern Mexico. Their geographic range includes the Mojave, Great Basin, and Colorado deserts. They are especially common in western Texas, southern California, Arizona, southern Utah, Nevada, and northern Mexico. Three subspecies of zebra-tailed lizards are recognized, which differ in their geographic range. Colorado zebra-tailed lizards occur in southern Nevada, southwestern Utah, southeastern California, and west Arizona. Northern or Nevada zebra-tailed lizards are found in central Colorado. Eastern or Arizona zebra-tailed lizards are distributed throughout central Arizona.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Callisaurus draconoides is a terrestrial lizard that lives in deserts or in semi-arid habitats with lose sandy soil. In rocky areas, this species is limited to sandy washes or occurs among boulders in canyons. In deserts, C. draconoides most often is found on the desert floor among shrubs, which are used for shade; rocks and boulders are used as perches for basking.

As a desert species, zebra-tailed lizards tolerate considerable variability in temperatures and rainfall. Throughout their geographic range, they experience high temperatures during the day and low temperatures at night. In the Mojave desert, temperatures range from 49°C (120°F) during the day to -7°C (20°F) at night. In the Great Basin, temperatures range from 14°C (57°F) to -8°C (18°F), and in the Colorado desert, temperatures range from 45°C (113°F) to -5°C (23°F). Because of this extreme temperature variation, zebra-tailed lizards tend to be diurnal, allowing periods of greatest activity during hours when the temperatures are most suitable. In addition, zebra-tailed lizards are capable of dealing with differing rainfall conditions. For example, in the Great Basin, rainfall varies from 2.3 to 3.0 cm per year; in the Mojave desert, it varies from 5.3 to 6.4 cm per year. In contrast, in the Colorado desert, rainfall ranges from 10.2 to 15.2 cm per year.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune

Physical Description

Callisaurus draconoides is a relatively large lizard, with males ranging in snout to vent length from 70 mm to 93 mm. Females are slightly shorter, typically ranging from 65 mm to 75 mm. Overall body length in both sexes ranges from 152 to 232 mm. Compared to other species of iguanids , both the tail and hind limbs of C. draconoides are considerably longer. In addition, the tail of C. draconoides is flattened. Subspecies of C. draconoides differ slightly in body measurements, particularly tail and hind leg length relative to overall body size.

Zebra-tailed lizards can be distinguished from similar species by their coloration and markings. Their dorsal surface ranges from gray to brown with yellow blotches. They have dark spots on both sides of their mid-dorsal line that extend from their neck to the bottom of the tail. The limbs and tail have 4 to 8 dark lateral cross bands separated by lighter areas, giving zebra-tailed lizards their distinct “zebra-striped” look. The intensity of coloration typically changes with temperature. Under higher temperature conditions, colors become much lighter; under mid-range temperatures, coloration typically matches that of their habitat.

Zebra-tailed lizards are sexually dimorphic, and males and females show differences in coloration and body markings. Both sexes have dark throats with radiating black lines; however, this pattern is particularly noticeable in males. Males also have sky blue to navy blue patches on both sides of the belly; these give way to two diagonal black bars that fade into brown on the sides of the body. Females are similar to males but lack the black and blue patches on the belly and have only faint black coloration on the sides and body. During breeding season, males exhibit a patch of metallic green-blue, sometimes orange and yellow, on the sides of their bodies and the lighter areas on their throat become pink.

The appearance of juveniles also differs from that of adults. Juveniles have dark dorsal spots that disappear as they age. These spots are completely gone once males reach sexual maturity. Young males also lack the black belly markings present in adult males.

Zebra-tailed lizards are similar, in some regards, to earless lizards and fringe-toed lizards . These three groups are sometimes referred to as “sand” lizards. These genera all have small scales on their heads, small granular scales on their backs, and folds of skin across their throats. In zebra-tailed lizards, these scales vary in size and texture across their bodies. Dorsal scales are small and smooth. Ventral scales are large, smooth, and flat. Scales on the head are small compared to those covering the rest of the body. Unlike earless lizards, both zebra-tailed and fringe-toed lizards have external ear openings. Belly markings also differ among these groups, with fringe-toed lizards having a single large blotched marking on the belly. Both zebra-tailed and earless lizards have two crescent-shaped belly markings. Belly markings in zebra-tailed lizards vary by location, occurring at or in front of their mid-body region.

• Other Physical Features
• heterothermic heterothermic

• Sexual Dimorphism
• male larger
• sexes colored or patterned differently
• male more colorful

Development

Callisaurus draconoides eggs usually hatch in August or September. Hatchlings range in size from 28 mm to 32 mm. Hatchlings are nearly identical to hatchlings of side-blotched lizards , a related species, and are often mistaken for them. However, hatchlings of C. draconoides curl and wag their tails, a behavior distinct to only this species.

Zebra-tail lizards hibernate twice during the year. They emerge from their first hibernation in April. At this point, hatchlings are known as juveniles. Most growth occurs between April, May, and June. By July, zebra-tailed juveniles have reached adult size, typically about 70 mm in length, and show signs of gonad development and body cycles. Sexual dimorphism, however, is not yet evident. Size differences between males and females begin to appear by late August, just before the second hibernation. When zebra-tailed lizards emerge from their second hibernation, they are sexually mature, with fully developed gonads, and are considered adults. Adult body length ranges from approximately 70 to 92 mm, with males typically ranging from 6 to 12 mm longer than females.

Reproduction

Zebra-tailed lizards are polygynous. The bond formed between males and a particular female may be strong or weak. Stronger bonds result in greater territory defense and greater duration of the male-female relationship. Once a bond is formed, the two court briefly, followed by copulation. It benefits males to mate with as many females as possible, typically resulting in higher hierarchical standing or rank. During breeding season, males attract mates by demonstrating that they are superior to other males. To do this, they perch themselves in an exposed area and perform a series of head bobs and push-ups. This is also used as a means of defending their territories. If a male enters another's territory, the resident male becomes highly aggressive.

• Mating System
• polygynous polygynous

Breeding season in Callisaurus draconoides begins in May and extends into August. Males reach peak reproductive state from May through July and show enlarged testes during this period. Females typically exhibit peak reproductive state from May through August. Both males and females reach reproductive maturity at about two years of age, with reproductively mature males (average snout-vent length = 70 mm) slightly larger than females (average snout-vent length = 65 mm). Like most other reptiles , C. draconoides is oviparous and has internal fertilization. Gestation lasts for 48 to 62 days. Females lay eggs in sheltered, humid environments to prevent desiccation. Average clutch size is 4 eggs, with each egg approximately 8 x 15 mm in size. Hatchlings are born with an "egg-tooth" - a tooth-like structure on their nose used to slice through the egg, which is lost shortly after hatching. Upon hatching, offspring are smaller but otherwise very similar in appearance to adults. Offspring are immediately independent of their parents.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• sexual sexual
• oviparous oviparous

Like most lizards , Callisaurus draconoides provides little parental care to offspring. Only pre-hatching parental investment occurs and includes choosing an appropriate nesting site, laying eggs in moist environments, and covering or sheltering eggs to prevent dessication. Females defend the area around their nest until hatching.

• Parental Investment
• female parental care female parental care
• pre-hatching/birth
  • protecting
    • female

Lifespan/Longevity

Callisaurus draconoides typically lives for 3 to 4 years in the wild, and adults rarely live past 3 years of age. Little is known about zebra-tailed lizards in captivity; however, closely related fringed-toed lizards reportedly live up to 8 years in captivity.

Behavior

Zebra-tailed lizards are active only during warmer months and hibernate typically from October to April. During active months, zebra-tailed lizards are diurnal and are more tolerant of high temperatures than most lizards. Whereas most lizard species burrow underground or hide beneath vegetation to avoid mid-day desert heat, zebra-tailed lizards are often seen basking in the sun in the middle of the day. Zebra-tailed lizards construct burrows, typically beneath shrubs, that are used to hide when they are threatened. They also use burrows for shelter during evening hours.

Zebra-tailed lizards are often solitary but have an elaborate social system in which social status is communicated to conspecifics via visual and olfactory cues. They are sometimes found in populations of varying sizes, but are highly territorial. Males may become highly aggressive when defending their territory.

Tail displays are used both in social communication and in predator-prey signaling. When zebra-tailed lizards detect a potential predator, they display the terminal portion of their tail, exposing the vivid black and white stripes while moving the tail in a vibrating motion. They also may curl their tail over their back, moving it in a side-to-side motion, to distract predators. Tail displays are seen most often when in open areas with little to no cover available. When threatened by a predator, zebra-tailed lizards hide in a nearby bush or burrow or sprint away, running in a zig-zag pattern and covering distances up to 50 m. They are considered to be one of the fastest desert lizards and can run up to 7.2 m/s. However, because of high desert temperatures, zebra-tailed lizards only move when defending their territories, chasing prey, or evading predators.

• Key Behaviors
• cursorial
• terricolous
• fossorial fossorial
• diurnal diurnal
• sedentary sedentary
• hibernation hibernation
• solitary solitary
• territorial territorial

Home Range

Home range size in zebra-tailed lizards varies in relation to age and sexual maturity. Individual home ranges often overlap, however, it is not clear if overlapping territorial boundaries are defended. Adult males have large home ranges that tend to overlap those of several females. In Nevada creosote scrub habitat, average home ranges size varies from 3500 m^2 to 6000 m^2.

Communication and Perception

Like most territorial lizards, zebra-tailed lizards defend their territories using physical gestures like push-ups or head nods. A characteristic unique to zebra-tailed lizards is the display of their black and white striped tail. "Wagging" of the tail is the most common form of intraspecific communication. Tail wagging is also performed when a predator is nearby. Tail wagging may be used to alert conspecifics of the presence of a predator or to signal fitness to the predator. Males and females both raise their tails when threatened by potential predators; however evidence suggests that males perform tail displays more often. In addition, zebra-tailed lizards found closer to ground cover are more likely to hide, whereas those encountered in the open are more likely to tail wag. Partial loss or shortening of the tail does not impede the ability or frequency of tail displays to predators; however, it does affect communication among conspecifics.

Little is known about perception in zebra-tailed lizards. They are believed to have well-developed vision and evidence suggests that taste buds may be used to identify individual females.

• Communication Channels
• visual visual

• Perception Channels
• visual visual
• chemical chemical

Food Habits

Although it is generally characterized as an insectivore, zebra-tail lizards consume plant material and the sloughed skin of other lizards. Common prey includes small invertebrates such as scorpions , flies , ants , spiders , worms , eggs, carrion, and other small vertebrates . Zebra-tailed lizards eat many different types of insect larvae, as well as leaves and flowers found throughout their geographic range. The diet of zebra-tailed lizards varies seasonally and regionally. Northern populations regularly consume grasshoppers during late summer and are more prone to eating vegetation during spring months when compared to other populations. More southerly populations regularly appear to prefer beetles and insect larvae.

Zebra-tailed lizards consume a majority of their food in the morning, however, they forage throughout the day as well. Zebra-tailed lizards are ambush predators. When prey nears, they cautiously approach with their tail raised and waving. During morning hours, they hunt for prey in the open, and during mid-day, they hunt for prey in more shady areas.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• mammals
• reptiles
• eggs
• carrion carrion
• insects
• terrestrial non-insect arthropods
• terrestrial worms

• Plant Foods
• leaves
• flowers

Predation

Snakes are common predators of zebra-tailed lizards and include red coachwhip snakes , pine snakes , glossy snakes , eastern kingsnakes , western patch-nosed snakes , and long-nosed snakes . Various species of rattlesnakes may also feed on zebra-tailed lizards, including horned rattlesnakes , western diamondback rattlesnakes , speckled rattlesnakes , and Mojave rattlesnakes . Larger lizards such as leopard lizards also feed on zebra-tailed lizards. Predatory birds include roadrunners , Swainson's hawks , American kestrels , and red-tailed hawks . Mammals that may prey on zebra-tailed lizards include kit foxes , coyotes , and gray foxes .

Callisaurus draconoides is well-camouflaged due to its gray-brown coloration. The bright, vivid colors of its tail are only seen on the ventral surface. In order to blend into its surrounding, it rests the bottom of its tail on the ground. Most lizard tails are autonomous, and can be shed or lost without incurring physical injury. This likely helps C. draconoides escape predators. Tail displays also are known to momentarily distract predators, allowing time for the lizard to escape. Tail wagging also may indicate individual fitness to the predator.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Callisaurus draconoides serves as prey for a wide range of species throughout its geographic range, including various snakes , birds , larger lizards , and some mammals . As insectivores, this species may help control insect pest populations. Parasites specific to this species are not currently known.

Economic Importance for Humans: Positive

As an insectivore, Callisaurus draconoides is valued because it helps controls insect pest populations. Like many other lizards , C. draconoides is often kept as a pet. This species is easily cared for but is short lived.

• Positive Impacts
• pet trade pet trade
• controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of Callisaurus draconoides on humans.

Conservation Status

Callisaurus draconoides is classified as a species of least concern on the IUCN's Red List of Threatened Species. It is abundant and maintains stable populations. This species occurs in many national parks and monuments, and as a result, its habitat is protected throughout much of its geographic range.

Additional Links

Encyclopedia of Life

Contributors

Ashly Goetting (author), Radford University, Megan Testerman (author), Radford University, Christine Small (editor), Radford University, John Berini (editor), Animal Diversity Web Staff.

References

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