Organic matter is organic matter and it only functions within a rather limited range of temperatures - cold is better because heat denatures proteins and when proteins are denatured (as in the heating of eggs), they don't work as biological materials any more and the change is irreversible. Cooled proteins are not generally denatured and the change may be reversible. Therefore, a body that has been cooled for a protracted period (for instance, by immersion in very cold waters) may be revived after measurable life signs have stopped. Generally, human temperatures above 100 degrees F. will do damage after a period of time unless . Other animals can handle it because of differences in surface area and the ability to dissipate heat in different ways.