Common Side-blotched Lizard – Tucson Herpetological Society

[vc_row][vc_column][vc_column_text]

Common Side-blotched Lizard (Uta stansburiana)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”1271″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Common Side-blotched Lizard (female), near Sonoyta, Sonora. Photo by Jim Rorabaugh[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1717″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Male Common Side-blotched Lizard. Photo by Cecil Schwalbe.[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1720″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Male Common Side-blotched Lizard. Photo by Cecil Schwalbe.[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1722″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Male Common Side-blotched Lizard, Muggins Mtns, AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1719″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Hatchling Common Side-blotched Lizard, Marijilda Cyn, Pinaleno Mtns. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1716″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Common Side-blotched Lizard, Photo by Young Cage[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”1718″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Common Side-blotched Lizard, Photo by Young Cage[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”1721″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Side-blotched Lizard, Photo by Young Cage.[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column width=”1/6″][/vc_column][vc_column width=”2/3″][vc_column_text]

Description

The Common Side-blotched Lizard (Uta stansburiana) is one of the most familiar and well-studied lizards in the western United States. This is a small (< 64 mm SVL), rather stocky lizard with a gular fold and ear openings. The dorsum is mostly brown to gray-brown with light stripes, blotches, or spots. In adult males the dorsal pattern is obscured by small light spots and often turquoise-blue speckling. Males also have enlarged post-anal scales and grow to a slightly larger size than the females, which have a maximum SVL of 58 mm. Adult females and juveniles have prominent dorsolateral and lateral light stripes with brown interspaces. Sexual dimorphism is greater in southern populations than in northern populations of this species (Parker and Pianka 1975). The venter is pale except for the blue, orange, or yellow of the throat. A blue-black patch, more prominent in adult males than in juveniles or adult females, lies on each side of the body just posterior to the forelimbs. Reproductive females develop orange coloration on the sides and tail. Scales on the dorsum are uniformly granular. Seven subspecies are recognized, five of which occur in the U.S. The Western Side-blotched Lizard (U. s. elegans) occurs in the 100-Mile Circle. There is some evidence that the Eastern Side-blotched Lizard (U. s. stejnegeri) may be a distinct species (Corl et al. 2009).

The Common Side-blotched Lizard is fairly distinctive in the 100-Mile Circle but is sometimes confused with the Ornate Tree Lizard (Urosaurus ornatus), which is more slender with a longer tail, has two rows of enlarged paravertebral scales on each side of the mid-dorsal line, and lacks the dark patches posterior to the forelimbs.

In the 100-Mile Circle, this is mostly a species of the Sonoran Desert from Tucson north to the Phoenix area and west to Organ Pipe Cactus National Monument. It occurs sparingly into semi-desert grassland and Chihuahuan desertscrub, and is occasionally found in riparian vegetation along rivers. Interestingly, there is only a single specimen in Herpnet and the University of Arizona collection from Santa Cruz County (5 miles N of Nogales) and only nine for Cochise County (Portal and east of Portal, Fort Bowie and vicinity, and Willcox Playa). But it is common in Sonoran desertscrub to the north and west of Tucson at elevations under about 1070 m elevation. In the Pinaleño Mountains it has been taken as high as 1615 m, which likely places it amidst oaks and junipers. Throughout its range, it is found as high as 2,700 m (Brennan 2009). The Common Side-blotched Lizard does well in a variety of terrain from flats and sand dunes to rocky canyons. Range wide it is found from southern Washington, Idaho, and Colorado through the southwestern U.S. and northwestern Mexico to southern Coahuila, eastern Durango, Chihuahua, western Sonora and northern Zacatecas, as well as throughout the Baja California Peninsula and many adjacent Gulf and Pacific islands.

The majority of the demographic and ecological work on this species has been done in Texas (Tinkle 1967), southern Nevada (Turner et al. 1970, 1982, Medica and Turner 1976 and others), and Oregon (Nussbaum and Diller 1977, Scoular et al. 2011). These studies show that the Common Side-blotched Lizard is short-lived, with most breeding occurring by animals one year or less of age. Survival from hatching to nine months was 19-31% in Rock Valley, Nevada, and few survived more than two years (Turner et al. 1982). Leopard Lizards (Gambelia wislizenii) were important predators and sources of mortality in southern Nevada. Densities ranged from 15-133/ha in southern Nevada and were correlated with the amount of precipitation in the preceding winter (Turner et al. 1974, 1982). Densities of 1-175/ha were recorded in other studies (see Nussbaum and Diller 1967, Parker 1974, Degenhardt et al. 1996, Gadsden and Castañeda 2012). Both males and females are territorial (Tinkle 1967), although less so in northern populations where there is often extensive overlap of home ranges, even within sexes. Common Side-blotched Lizards tend to live longer, and the percentage of individuals that do not breed in their first year is greater with increasing latitude and/or elevation (Nussbaum and Diller 1976). Rainfall, lizard density, and gender have significant effects on home range size, although the effects of density and gender appear to be more robust than rainfall (Scoular et al. 2011). Parker and Pianka (1975) concluded that ecological challenges were mostly climatic for northern populations whereas predation and competition were the most important limiting factors for southern populations.

This is usually described as a diurnal species, becoming bimodal (active mornings and late afternoon) as temperatures rise in late spring or summer. However, Grismer (2002) noted nocturnally active lizards in Baja California and islands in the Gulf of California from April through September. Most activity occurs from March through October; however, in the lowlands and the southern portions of its range the Common Side-blotched Lizard may be active throughout the winter. The Common Side-blotched Lizard is usually found on the ground or on rocks. It rarely climbs into trees or shrubs.

Mating strategies, timing of reproduction, clutch size, and number of clutches produced by a female in a year vary with geography, as do a number of other ecological processes (Fitch 1970, Parker and Pianka 1975, Corl et al. 2009). Northern populations tend to breed most consistently in the spring, when clutch sizes are greatest. In the south the breeding season is extended. In Durango, Mexico, hatching was timed to the wet season in summer and autumn (Gadsden and Castañeda 2012). In Baja California Sur breeding occurs year-round (Grismer 2002, Goldberg 2012). Both sexes mature at 37-44 mm SVL (Parker and Pianka 1975, Goldberg 2012). One to seven clutches of 1-8 eggs are laid per year by females (Medica and Turner 1976, Brennan 2009). In northern populations, usually 1-2 clutches are laid, and two or more are laid per season by southern females (Parker and Pianka 1975). Eggs hatch 60-70 days after they are laid (Tinkle 1967). Hatchlings are 18-23 mm SVL and can reach adult size in as little as three months, but usually do not breed until the following year.

Parker (1974) studied a population of Common Side-blotched Lizards at South Mountain Park south of Phoenix. Mean home range for adult males and females were 446 m² and 121 m², respectively. Abundance was greatest in two flatland areas and reduced on adjacent slopes. Population densities varied seasonally. Adult density was high in February 1966 (50/ha), but declined rapidly through April and May (7/ha), likely due to predation. Females produced clutches in March, but few survived to produce second or third clutches. Most hatching occurred from mid-May to mid-June. Densities of up to 131 juveniles per ha were recorded. Parker (1974) estimated that some hatchlings reached adult size by September.

Common Side-blotched Lizards are opportunistic sit and wait predators, consuming mostly arthropods. Beetles, grasshoppers, crickets, ants, and termites are common in the diet. Small lizards are occasionally consumed, as well (Parker and Pianka 1975).

This lizard is listed as a species of least concern on the 2013 IUCN Red List. With a valid Arizona hunting license, 20 can be collected per day or held in aggregate, alive or dead, except that take is prohibited in protected areas such as National Park Service units, without special authorization. The Common Side-blotched Lizard is eliminated from areas of urbanization and intensive agriculture, but there is no reason to believe it is declining in wildland areas.

Common Side-blotched Lizard (Uta stansburiana)

Description

DONATE TODAY

THANK YOU FOR YOUR SUPPORT

Search the Site

CONTACT THS

Archive