Click on pictures to enlarge
(Sceloporus
undulatus)
Identification: Upper side with spiny scales; scales on rear of thigh keeled and overlapping; coloration extremely variable, usually striped or crossbanded (see following); total length up to about 19 cm (7.5 inches).
Mature male: Two enlarged scales on underside of base of tail just behind vent;
underside of base of tail with two bulges (from hemipenes).
Mountainous southwestern Colorado: light stripes along sides of
back of male usually distinct and not crossed by dark bands; blue patches on
sides of throat and belly, with wide black margin in adult males.
|
Eastern edge of Rockies and rocky areas in southeastern Colorado : Back crossed by dark wavy
bands; blue patches on throat meet at midline in adult male; lips, chin,
and/or face of adults usually orange or yellow during breeding season
(peak coloration in May), though some adult males may instead have
extensive black coloration.
|
 |
 |
 |
Sandy areas of eastern Colorado: light stripes
along sides of back usually distinct and not crossed by dark bands;
usually no blue patches on sides of throat.
|
| Western Colorado: blue patches on sides of throat usually do not meet at midline; lips and chin never orange or yellow; dark crossbands on back often faint, discontinuous, or absent; sometimes upper side is patternless; dark stripe usually present sides of adult male. |  |
 |
Colorado Distribution:
Throughout most of Colorado, except
the high mountains in the central part of the state.
Habitat:
Throughout most of Colorado, this
species inhabits sunny, rocky habitats including cliffs, talus, old lava flows
and cones, canyons, hogbacks, and various outcroppings. Vegetation adjacent to
and among the rocks is variable and may include coniferous montane forest (e.g.,
ponderosa pine, Douglas-fir), piņon-juniper woodland, mountain shrubland,
semidesert shrubland, or various grasses and forbs. Perch sites often are on
rocks but also include trees, logs, piles of debris, buildings, and dirt banks,
though the lizards also may spend a considerable amount of time on the ground.
In southern Colorado, common habitat includes montane woodland with downed logs.
In northeastern, east-central, and extreme southeastern Colorado, this lizard is
a ground-dweller, occurring in areas with soft sandy soil and often associated
with barren wind-eroded areas and patches of yucca. In some areas of eastern
Colorado, the species is associated with rocky scarp woodlands and sandstone- or
limestone-capped bluffs and buttes, and in prairie habitats, it commonly occurs
in association with isolated rocks, debris, or other cover. Burrows, spaces
under rocks, and various crevices are used as shelter during extended periods of
inactivity or as refuges from danger.
Life History:
Females produce one or more clutches
of eggs in May, June, or July, sometimes in August. The earliest hatchlings
emerge in mid- to late July in some areas, but not until August in other
locations.
Note: Recent studies suggest that Sceloporus undulatus
comprises more than one species, but the geographic scope of those species has
not yet been fully resolved.
Revised: July, 24 2003