Shelter site selection by Mastigoproctus giganteus in an atypical microhabitat in the northern Chihuahuan Desert characterized by hard adobe soils is described for the first time. The majority of the 321 whipscorpions (70.4%) were found within rock crevices during periods of highest daytime ambient temperatures, as compared to those found under plant debris (4.4%) or inside small mammal holes (25.2%). The percentage of available crevices, holes or plant debris that were occupied by whipscorpions was 41.5, 3.8 and 7.3%, respectively. Most occupied crevices (66.7%) were in the shade. Depths of occupied crevices ranged from 6.4–36.7 cm. Crevice widths ranged from 0.7–2.9 cm. Whipscorpions used crevices whose height above the surface of the ground ranged from 6.5 cm–1.1 m. No whipscorpions were observed at the ground surface, even in shaded areas, between 0645 and 1910 hr (CST).