What is the likely homeostatic reason for developing a fever ?

The body is too cold, so the body tries to keep itself cool by overheating. But, though a likely scenario, would require the body to be frostbitten, and overexposed, and would supply as a sort of plan B for the body to maintain an equilibrium with its temperature; reacting to the conditions around it, and trying to maintain balance within itself.

Answerstratovolcanoes///near or in the ring of fire;