Temperature-Independent Morning Emergence in Lizards of the Genus Phrynosoma

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Science  23 Nov 1962:
Vol. 138, Issue 3543, pp. 891-892
DOI: 10.1126/science.138.3543.891


An investigation of the relationship of morning emergence and body temperature in Phrynosoma demonstrated a rhythmic anticipation of conditions favorable for normal activity. Such a rhythm offers a mechanism by which ectothermic reptiles can use safe nocturnal shelters without loss of activity time in the morning.