First Advisor

Stanley S. Hillman

Date of Publication


Document Type


Degree Name

Master of Science (M.S.) in Biology






Northern alligator lizard, Lizards -- Physiology, Metabolism, Body temperature -- Regulation



Physical Description

1 online resource (45 p.)


The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and not by fluctuations around this temperature. The metabolic cost of behavioral thermoregulation did not change with corresponding changes in reinforcement magnitude. This indicates that eurythermality is the recorded effect of lizards behaviorally regulating to different TB in a stenothermic manner, rather than of random TB fluctuations in a wide range of normal activity (the classical view of eurythermality).


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