the.com/shivering
Your body throwing a tiny earthquake to warm itself, no permission asked.
means Involuntary muscle trembling that generates heat to fight cold, fear, or fever.
from From Middle English chiveren, possibly tied to chavel, meaning to chatter the jaws — the teeth got there first.
Heat hackRapid muscle contractions burn energy purely to make warmth.
Fever twistYou shiver while burning up because the brain raised the target.
Goosebumps cousinBoth are leftovers from fur we no longer have.