We can test our laboratory conclusion that the lizard cannot regulate its body temperature. To do this, we return the lizard to its desert habitat, but we continue to measure its body temperature as it goes about its normal behavior. In this environment, air temperature can change 40°C in a few hours (Figure 41.8).
In contrast to what we observed in the laboratory, the lizard's body temperature is sometimes considerably different from the environmental temperature. The lizard achieves this by using behavior to alter its heat exchange with the environment. Its behavioral strategies include spending time in a burrow, basking in the sun, seeking shade, climbing vegetation, and changing its orientation with respect to the sun.
Our conclusion must be that the lizard can regulate its body temperature quite well, but that it does so by behavioral mechanisms rather than by internal metabolic mechanisms. In our laboratory experiment, the lizard could not use its ther-moregulatory behavior, but in its natural environment it could move from place to
The lizard returns to the constant temperature of its burrow at night.
41.8 An Ectotherm Uses Behavior to Regulate Its Body Temperature The lizard's body temperature is dependent on environmental heat,but it can regulate its temperature by moving from place to place within its environment.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.