Fig. 3.

(A–C) Phase diagrams of cold-tolerance limits and maximum operative body temperature for reptiles, insects, and amphibians. The white region shows where species have a physiological thermal-safety margin even in the coldest operative temperatures whereas the gray region shows where species are dependent on behavior or microhabitat use to avoid minimum operative temperatures in open habitats. (D–F) Cold thermal-safety margins as a function of latitude based on minimum exposed operative temperatures (T_e,min − CT_min; circles). Positive values indicate physiological thermal safety whereas negative values represent thermal danger and reliance on cold-buffering habitats and behaviors. Colors indicate elevation, and lines show best-fit regression from linear models that were significantly different from zero.