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Tiger Whiptail (Aspidoscelis tigris)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”1314″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Tiger Whiptails mating. ©2013 Dancing Snake Nature Photography[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2042″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Juvenile Tiger Whiptail. Photo by Robert L. Bezy and Kathryn Bolles[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2047″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptails mating. 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=”2048″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Young juvenile Tiger Whiptail, Yuma Co., 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=”2049″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Shuffling tracks of a Goode’s Horned Lizard, Pinta Sands, Cabeza Prieta NWR. 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=”2054″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptail, Yuma Desert. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2053″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Hybrid Tiger X Sonoran Spotted Whiptail. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2051″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptails mating. ©2013 Dancing Snake Nature Photography[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2055″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Photo by Robert Bezy and Kathryn Bolles[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2041″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptail, Photo by Young Cage[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2043″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptail, adult male, Cochise Cnty. Note the 33 femoral pores (33-48 in the species), and enlarged pre-anal scales. Males do not have enlarged post-anal scales. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2057″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptail, adult male venter. Note darkening of chin, throat, and chest, somewhat enlarged mesoptychial scales, and 8 rows of quadrangular ventral scales. Cochise Cnty. Photo by Jim Rorabaugh[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2052″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Whiptail, Cochise Cnty, postantebrachial scales granular, not enlarged. Photo by Jim Rorabaugh[/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 Tiger Whiptail (Aspidoscelis tigris) is a moderately-sized whiptail (< 110 mm SVL in our area) that throughout its extensive range is quite variable and undergoes ontogenetic or developmental changes in color and pattern from hatchling to old adult.  As with all whiptails, this is a long and slender lizard with granular dorsal scales on the body, larger, keeled scales on the long tail, large plate-like scales on the pointed head, and eight longitudinal rows of quadrangular smooth scales on the venter.  The scales on the central rear surface of the forearm (postantebrachial scales) are not enlarged, and those just anterior to the gular region of the throat (mesoptychial scales) are only somewhat enlarged (see image gallery) and grade into the granular gular scales.

The dorsum of the body on hatchlings and young juveniles is dark brown to black with 4-6 light stripes (lateral stripes may be indistinct) and light spots or mottling between the stripes.  The tail is usually blue to blue-green.  As the lizards age, the tail turns a very dark brown to black and the stripes fade.  The dorsum of adults is mostly dark brown to black with a light reticulation on the back and tiger banding on the sides.  The venter of adult males shows considerable darkening, especially on the chin, throat, and chest.  Adult females have less darkening of the venter, and juveniles usually have none.

The color pattern just described occurs throughout the 100-Mile Circle, except that it may be replaced on the very southeastern edge of the circle, perhaps in sandy areas along the Río Sonoyta drainage, by a much lighter-colored form that occurs broadly over the Gran Desierto de Altar and the Yuma Desert.  In that form, the dorsal ground color of older juveniles and adults is buffy tan with faint reticulations and tiger banding (see image gallery). The adult venter is not nearly as dark as Tiger Whiptails elsewhere in the 100-Mile Circle. Range wide, five subspecies are recognized. The subspecies A. t. punctilinealis occurs in the Circle.

This is a distinctive whiptail, not likely to be confused with other lizards in our area. The Tiger Whiptail is the only whiptail in the Circle with conspicuous darkening of the chin, throat, and chest in adult males, and the only one to have a dark, reticulated and tiger-banded dorsal pattern in adults.  It is also the only whiptail in our area to consistently have granular (not enlarged) postantebrachial scales. The Arizona Whiptail (Aspidoscelis arizonae) has scales in that region ranging from small and granular to moderately enlarged, but it is striped with no light spots or mottling in the dark fields between the stripes.  The Tiger Whiptail is usually the only whiptail occurring in Sonoran Desert flats and bajadas. Where it occurs with the unisexual Sonoran Spotted Whiptail (Aspidoscelis sonorae – the eastern edge of the Sonoran Desert, Chihuahuan desertscrub, and semi-desert grasslands), hybrids may occasionally be found (see image gallery).

In the 100-Mile Circle, the Tiger Whiptail is found in most areas below 1280 m, but is absent from the mountains and higher valleys, most of Santa Cruz County, and the southern half of the Sulphur Springs Valley. It occurs in Sonoran desertscrub (both the Arizona Upland and Lower Colorado River subdivisions), Chihuahuan desertscrub, and semi-desert grassland. Based on habitat use elsewhere in Arizona, it likely ranges occasionally into oak savanna. At the higher elevations, it is a species of valleys and bajadas, but in the deserts it can be equally abundant on slopes and flats.  It also manages to persist to some degree in agricultural areas and on the edge of suburbia. Outside the 100-Mile Circle, the Tiger Whiptail occurs north to Oregon and Idaho, south to Sinaloa and the tip of the Baja California Peninsula, west to the coast of California, and east to western New Mexico and western Colorado.

The Tiger Whiptail is primarily diurnal, but on the lower Colorado River is often active as much as 30 minutes before sunrise in the heat of summer (Vitt and Ohmart 1977). Its activity is bimodal – mornings and late afternoon – in summer, but it is active throughout the day in the spring. At South Mountain and vicinity, south of Phoenix, Tiger Whiptails emerge from dormancy in March, adults remain active until the end of September, and juveniles are active intermittently until mid to late November (Parker 1972).  At higher and cooler sites, seasonal activity periods are shorter.  At South Mountain, females mature at 63-66 mm SVL, and males mature at about 71 mm SVL.  In southern Nevada, individuals > 80 mm SVL are mature (Turner et al. 1969).  South Mountain females are gravid from April to early August and produce one or two clutches of 1-4 eggs. A maximum of 8 eggs per clutch is reported for the species and mean clutch size ranges from 2.05-3.43 depending on location. Hatchling emergence at South Mountain occurs from mid-June to early August, but varies from year to year. Hatchlings are 37-41 mm SVL.  In 1965 and 1966, spring densities at South Mountain and vicinity were 13/ha and increased to 36/ha in late summer (Parker 1972).  Tiger Whiptails are relatively long-lived. Survivorship in southern Nevada after the first 8-10 months of life was 60% per year, and some lizards lived at least seven years (Turner et al. 1969).

This is an active forager, moving from bush to bush, poking and scratching with its front feet through leaf litter and soil for prey, which includes a variety of invertebrates, but also some lizards. Tiger Whiptails sometimes climb into low branches of shrubs in pursuit of prey.  On the lower Colorado River, the most important dietary items by volume were, in order of importance, Isopterans (termites), Homopterans (sucking insects, such as true bugs and cicadas), and Coleopterans (beetles and weevils, Vitt and Ohmart 1977). Lizards taken are usually small, but Randy Babb and Tom Brennan (2013) observed a Tiger Whiptail carrying off a juvenile Desert Iguana in the Yuma Desert.  In Glendale, AZ, I watched an adult Tiger Whiptail eat a juvenile Mediterranean Gecko.  Percent volume of lizards in the diet on the lower Colorado River was only 0.03.

The Tiger Whiptail is listed as a species of least concern on the 2014 IUCN Red List. With a valid Arizona hunting license, twenty Tiger Whiptails can be collected per day or held in possession in the aggregate alive or dead.  However, take is prohibited without specific authorization in National Wildlife Refuges, National Monuments, and other protected areas. There is no reason to believe the Tiger Whiptail is declining in wild lands; however, it is eliminated from areas of heavy urbanization, intensive mining, and other heavy forms of land use.  This lizard was known until recently as Cnemidophorus tigris.

Suggested Reading:

Babb, R.D., and T.C. Brennan. 2013. Aspidoscelis tigris (Tiger Whiptail). Diet. Herpetological Review 44(3):507. 

Brennan, T.C., and A.T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZ.

Degenhardt, W.G., C.W. Painter, and A.H. Price. 1996.  Amphibians and Reptiles of New Mexico. University of New Mexico Press, Albuquerque.

Parker, W.S. 1972. Ecological study of the western whiptail lizard, Cnemidophorus tigris gracilis, in Arizona Herpetologica. 28 (4): 360-369.

Sullivan, B.K. 2009. Tiger Whiptail Aspidoscelis tigris (Baird and Girard, 1852). Pages 394-397 in Jones, L.L.C., and R.E. Lovich (eds.), Lizards of the American Southwest: A Photographic Field Guide.  Rio Nuevo Publishers, Tucson, Arizona.

Turner, F.B. P.A. Medica, J.R. Lannom, and G.A. Hoddenbach. 1969. A demographic analysis of fenced populations of the whiptail lizard, Cnemidophorus tigris, in southern Nevada. The Southwestern Naturalist 14:189-201.

Vitt, L.J., and R.D. Ohmart. 1977. Ecology and reproduction of lower Colorado River lizards: II. Cnemidophorus tigris (Teiidae), with comparisons. Herpetologica 33(2):223-234.

Author: Jim Rorabaugh

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