Natural History Notes Holbrookia lacerata (Spot-tailed Earless Lizard) Burying Behavior

Authors: Neuharth, D., D.K. Walkup, S. Frizzell, J. Kachel, C.S. Adams, T. Johnson, T.J. Hibbitts, and W.A. Ryberg

Full text originally published in the Herpetological Review 49(3). Natural History Notes (PDF)

HOLBROOKIA LACERATA (Spot-tailed Earless Lizard)

BURYING BEHAVIOR. Burying behavior is well documented within the phrynosomatid sand lizards, but no literature exists on the burying habits of Holbrookia lacerata. Other members of this clade prefer sandy soils and are known to bury in soft soils to avoid extreme temperatures and predation, and to lay eggs (Axtell 1956. Bull. Chicago Acad. Sci. 10:163–179; Brennan and Holycross 2009. A Field Guide to the Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix. 150 pp.; Hibbitts and Hibbitts 2015. Texas Lizards: A Field Guide. University of Texas Press, Austin. 351 pp.). Uma notata (Colorado Desert Fringe-toed Lizard) have been documented burying themselves in coarse pebbly sand (Pough 1970. Copeia 1970:145). However, clay soils are preferred by H. lacerata (Hibbitts and Hibbitts, op. cit.). Over the course of a telemetry study on H. lacerata from May to July 2017, a number of individuals were discovered buried in multiple substrates and under varied weather conditions. All lizards used in the study were adults. Two sites were used for this study: one located in Crockett County, Texas, USA (ca. 30.9300°N, 101.1916°W; WGS 84) and another located in Val Verde County, Texas, USA (ca. 29.3712°N, 100.7722°W; WGS 84). Lizards from these sites represent two separate subspecies: H. l. lacerata (Northern Spot-tailed Earless Lizard) at the Crockett County site and H. l. subcaudalis (Southern Spot-tailed Earless Lizard) at the Val Verde County site. The Crockett County site consists of a mixture of Chihuahuan thornscrub and arid grasslands. The Val Verde County site is heavily modified and consists of a mowed airfield surrounded by Chihuahuan thornscrub. Both sites are primarily clay soils intermixed with varied amounts of limestone. In Val Verde County, eight individual lizards were observed at least partially buried a combined total of 37 times. Many of these events were sequential encounters in the exact same location. Assuming these represented times the lizards did not become active and then rebury themselves at the same location, lizards were discovered buried 17 times. Five lizards were female, two of which were gravid during and after our observations. With respect to weather, 78% of encounters with buried lizards occurred during overcast or rainy conditions, while the remaining observations were made during sunny conditions. Lizards never buried more than 1 cm deep, and were occasionally partially exposed. One female lizard was documented twice buried into a harvester ant (Pogonomyrmex sp.) mound. Four lizards were recorded buried along caliche roads in shallow, relatively loose gravel. Two lizards were discovered buried in the detritus and shallow soil occupying cracks in an abandoned asphalt runway. Additionally, 325 of 578 total observations (56.2%) of lizards were found completely hidden underneath thick forbs or grass bunches but not buried. Most of these lizards were hiding in detritus, primarily dead grass, beneath the plants. In total, lizards were hidden 62.6% of encounters. In Crockett County, 10 individual lizards were observed at least partially buried a combined total of 82 times. Excluding sequential encounters in the same exact location, lizards were observed buried 40 times. Six of these lizards were female, and four were male. Five of the females were gravid during burying observations. In contrast to Val Verde County, only 25% of encounters with buried lizards in Crockett County occurred under overcast or rainy conditions. Lizards were recorded buried, or actively burying, in caliche roads 13 times. Additionally, 144 of 475 total observations (30.3%) of lizards were found completely hidden beneath thick forbs or grass bunches, and under dry cattle feces in three cases. Similar to the Val Verde County site, detritus beneath the plants were used as cover. In total, lizards were hidden 47.6% of encounters. Burying behavior at both sites seemed to coincide with longer periods of inactivity (i.e. cool, overcast days). Short-term refuge use was most often just the cover of vegetation or detritus. Herpetological Review 49(3), 2018 NATURAL HISTORY NOTES 537 Other members of this genus have been shown to be extremely wary, readily sprinting away when approached (Cooper 2000. Behaviour 137:1299–1315). This wariness, in conjunction with their cryptic pattern and the burying habits described here, suggest that the detection probability of this species could be extremely low.

 

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