Taking Temperatures - Maintaining Thermal Regulation
Photograph Copyright 2006 Wynne Brown
Why do reptiles, such as snakes and lizards, bask in the sun? In its native South Africa, this sungazer is called an ouvolk, or "old person," for its habit of sitting in the sun for hours outside its burrow. Reptiles are ectothermic, which means they rely on outside heat to regulate their temperature. This particular sungazer is controlling its internal temperature by choosing a mix of sun and shade.

Mammals and birds are endothermic, which means they "make" their own heat and maintain the same internal temperature in either hot or cold circumstances.

But how could you test this theory? It'd be easy if you were in the same room with a mammal and a reptile - but what if you don't want to handle snakes and rats? Can you measure how hot or cold an animal is just by using images?

You be the judge.

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