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Desert Banded Gecko
Coleonyx variegatusFamily: Eublepharidae Order: Squamata Class: Reptilia
DISTRIBUTION, ABUNDANCE, AND SEASONALITY
The banded gecko exists in two forms in California. The desert banded gecko (C. v. variegatus)
is common to uncommon in the desert from northern Inyo Co. south to Mexico. It is found from
below sea level to 1750 m (5750 ft) (Macey and Papenfuss 1991) in all desert habitats up to
pinyon-juniper
or mixed chaparral, but is most abundant in sandy flats and
desert washes
(Klauber 1945).
The San Diego banded gecko (C. v. abbotti) occurs in coastal and cismontane southern California
from interior Ventura Co. south, although it is absent from the extreme outer coast. It is uncommon
in coastal scrub and chaparral, most often occurring in granite or rocky outcrops in these habitats
(Klauber 1945, Stebbins 1972).
SPECIFIC HABITAT REQUIREMENTS
Feeding:
Banded geckos are opportunistic foragers on insects and other arthropods including
beetles, termites, spiders, grasshoppers, sowbugs, and insect larvae (Klauber 1945, Parker and
Pianka 1974).
Cover:
During the day, geckos stay under rocks, rock caps, boards, fallen yucca stems, cow
dung and other litter, or may seek refuge in mammal
burrows
(Klauber 1945, Miller and Stebbins
1964). Banded geckos hibernate in burrows (Parker 1972).
Reproduction:
Eggs are probably buried in ground or under rocks (Mayhew 1968).
Water:
Water is obtained from food (Miller and Stebbins 1964).
Pattern:
The desert banded gecko occurs in a wide variety of habitats, however the San
Diego banded gecko prefers rocky or granite outcrops.
SPECIES LIFE HISTORY
Activity Patterns:
Nocturnal.
The peak activity period is two hours after sunset (Klauber
1945, Miller and Stebbins 1964), however, banded geckos may come out in the late afternoon
to absorb heat (Brattstrom 1952). They are active April through October with a peak in May.
Juveniles may be intermittantly active November through March (Klauber 1945, Parker 1972).
Seasonal Movements/Migration: No data.
Home Range:
Parker (1972) estimated densities of 12-25 geckos/ha (5-10 acre) in Arizona.
By driving roads at night, Klauber (1945) found 19.4 per 160 km (100 mi) in the Borrego area
in San Diego County. On the best trips he encountered one gecko on the road every 3.2 km
(2 mi), or 24 specimens in 78.4 km (49 mi).
Territory:
Aggressive interactions between males in the laboratory suggest the possibility
of territoriality in the field, or may be a means of sex recognition in a species that is not sexually
dimorphic. During the day geckos tended to aggregate in shelters in the laboratory (Greenberg
1943).
Reproduction:
Mating occurs from April to May, eggs are laid from May through September,
and hatchlings appear July through November (Stebbins 1954, Fitch 1970, Parker 1972, Miller
and Stebbins 1964). Males emerge in April and attain peak testes size in May followed by
testicular regression (Parker 1972). The highest frequency of gravid females was in May and
June (Parker 1972). Clutch size is two eggs, one per ovary or oviduct. Eggs are sometimes laid
one at a time on different days (Parker 1972). Females store sperm and can produce multiple
fertile clutches per season (Mayhew 1968, Parker 1972). Two to three clutches per season are
produced. Estimates of incubation time are 30 to 45 days. Males and females reach maturity
within one year at 52 mm (2.08 in) and 56 mm (2.24 in), respectively (Fitch 1970, Parker 1972).
Niche:
Predators include
leaf-nosed snakes,
western patch-nosed snakes,
night snakes,
sidewinders,
western diamondback rattlesnakes,
coachwhips, and
zebra-tailed lizards
(Klauber 1945, Funk 1965, Parker 1972). Other possible predators are
tarantulas,
large centipedes, solpugids, other rattlesnake species,
coyotes
and
kit foxes
(Parker 1972). Tail autotomy is believed to be an important defense mechanism from enemies (Parker 1972,
Parker and Pianka 1974). The tail is raised and undulated at the approach of a
predator
(Johnson and Brodie 1974). The banded gecko can have considerable dietary overlap
with sympatric
diurnal
lizards
(e.g., whiptails).
Therefore, time of activity may be of
limited importance in reducing dietary overlap and competition (Huey and Pianka 1983).
REFERENCES
Brattstrom, B. H. 1952. The food of the night lizards, genus Xantusia. Copeia 1952:168-172.
Dixon, J. R. 1970a. Coleonyx. Cat. Am. Amphibians and Reptiles 95.1-95.2.
Dixon, J. R. 1970b. Coleonyx variegatus. Cat. Am. Amphibians and Reptiles 96.1-96.4.
Fitch, H. S. 1970. Reproductive cycles in lizards and snakes. Univ. Kans. Mus. Nat. Hist. Misc.
Publ. 52:1-247.
Funk, R. S. 1965. Food of Crotalus cerastes laterorepens in Yuma County, Arizona.
Herpetologica 21:15-17.
Greenberg, B. 1943. Social behavior of the western banded gecko, Coleonyx variegatus Baird.
Physiol. Zool. 16:110-122.
Huey, R. B., and E. R. Pianka. 1983. Temporal separation of activity and interspecific dietary
overlap. Pages 281-290 in R. B. Huey, E. R. Pianka, and T. W. Schoener, eds. Lizard Ecology.
Harvard Univ. Press, Cambridge. 501pp.
Johnson, J. A., and E. D. Brodie, Jr. 1974. Defensive behavior of the western banded gecko,
Coleonyx variegatus. Anim. Behav. 22:684-687.
Klauber, L. M. 1945. The geckos of the genus Coleonyx with description of new subspecies.
Tran. San Diego Soc. Nat. Hist. 10:133-216.
Macey, J. R. and T. J. Papenfuss. 1991. Reptiles. 291-360. IN Natural History of the White-Inyo
Range eastern California. C.A. Hall, Jr. Ed. Univ. Calif. Press, Berkeley, California. 536 pp.
Mayhew, W. W. 1968. The biology of desert amphibians and reptiles. Pages 195-356 in G. W.
Brown, Jr., ed. Desert Biology, Vol. 1. Academic Press, New York. 638pp.
Miller, A. H., and R. C. Stebbins. 1964. The lives of desert animals in Joshua Tree National
Monument. Univ. California Press, Berkeley. 452pp.
Parker, W. S. 1972. Aspects of the ecology of a Sonoran desert population of the western
banded gecko, Coleonyx variegatus (Sauria, Eublepharinae). Am. Midl. Nat. 88:209-220.
Parker, W. S., and E. R. Pianka. 1974. Further ecological observations on the western banded
gecko, Coleonyx variegatus. Copeia 1974:528-531.
Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill, New
York. 536pp.
Stebbins, R. C. 1972. California amphibians and reptiles. Univ. California Press, Berkeley.
152pp.
Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. 2nd ed., revised.
Houghton Mifflin, Boston. 336pp.
California Department of Fish and Game. California Interagency
Wildlife Task Group. 2005. California Wildlife Habitat Relationships version 8.1 personal computer program. Sacramento, California.
Nelson Ryan Wong, Western Banded Gecko. San Diego Natural History Museum
Western Banded Gecko
Coleonyx variegatus
Western Banded Gecko
EUBLEPHARIDAE
Coleonyx comes from the Greek koleos, meaning a sheath and onych, meaning nail or claw, while variegatus comes from the Latin vario, meaning variegated.
Description:
The Western Banded Gecko is a medium-sized gecko with soft skin, short limbs, a pointed snout, large eyes, and functional eyelids. Like other Eublepharid geckos, this species has movable eyelids, slender toes that lack villi, and pointed claws. Adults are approximately 6 inches (150 mm) in total length, with females measuring about 2.8 inches (70 mm) snout-vent length, and the smaller males measuring about 2 1/2 inches (63 mm) snout-vent length.
Adults are typically pale-yellow or light-gray in color. Red-brown spots cover the top of the head, and red-brown spots or bands cross the back.
Subspecies: There have been as many as seven subspecies recognized: the San Diego Banded Gecko (C. v. abbotti); the Desert Banded Gecko (C. v. variegatus); the San Lucan Banded Gecko (C. v. peninsularis); the Utah Banded Gecko (C. v. utahensis); and the Tucson Banded Gecko (C. v. bogerti); the Sonoran Banded Gecko (C. v. sonoriensis); and the Santa Inez Island Banded Gecko (C. v. slevini). All appear to intergrade widely.
Range and Habitat
The Western Banded Gecko ranges throughout the southwestern United States and northwestern Mexico, closely mirroring the combined Mojave and Sonoran Deserts.
This species is usually found in open areas, often near rocks, and may seek shelter under them, or in crevices. It is found from sea-level up to an elevation of 4000 feet.
Natural History
Well-known herpetologist Laurence Klauber noted that this lizard was found more often at night in the Colorado Desert than all snakes and lizards put together. (Klauber, 1945)
Behavior: Western Banded Geckos are primarily nocturnal, foraging at night and hiding under a variety of objects such as rocks, stems, and other types of debris during the daytime. They are most active during the spring.
When they run, this species holds its tail curved over its back, and sways from side to side. Its tail breaks off easily -- caudal autonomy is considered a defense mechanism. Other defensive tactics include squeaking, ejecting viscous liquids, and limb extension.
Prey and Predators: Their diet includes insects and other arthropods. Occasionally, they will eat parts or all of their own skin after shedding. Fat is stored in their tails for times of food scarcity. The Western Banded Gecko is a food source for many predators, such as snakes. These geckos are believed to be able to detect the chemical signals left by snakes, which gives them the chance to avoid them.
