Not all organisms maintain their body’s core temperature the same way. Some control it internally like we do. We’re endothermic. Reptiles for example are not. They’re ectothermic. Two pennies for who guesses how these fine specimens maintain their temperature. Do they:
A) Run for heat?
B) Shiver for heat?
C) Sit where the sun shines?
They sit where the sun shines, dear audience, they just sit there until it gets too hot. And what do they do when it gets too hot? Well, funny you should ask. They move their scaly little selves to a shady place. Why didn’t our monkey-faced ancestors think of that? (They did, long story.)
Needless to say, a lot of ectothermic organisms live in extremely stable regions where temperature doesn’t fluctuate wildly.
Fun fact: that bit in the brain, the hypothalamus, is responsible for temperature homeostasis. Thermoreceptors pick up increases and decreases in optimal body temperature and send signals to effectors to act…