She asked me if I was okay, the technician, while the small warm animal trembled against my chest, and I told her the trembling was interesting, because shivering is the body burning stored chemical energy as waste heat, muscles firing out of phase precisely so their motion cancels and produces almost nothing but warmth. A body deliberately being inefficient to stay alive.
The animal is warm because somewhere inside each of its cells, structures no wider than a few hundred atoms are prying electrons off of the molecules it ate this morning and letting them fall, in careful steps, down a voltage gradient steeper, per meter, than a lightning bolt. That controlled falling is the whole trick.
That is what "alive" means, thermodynamically: a pocket of matter that pumps hard enough, moment to moment, to hold itself in a state overwhelmingly less probable than the room it sits in.
I could feel its heart going against my forearm. Fast, maybe twice mine. Every mammal gets roughly the same billion and a half heartbeats; the small quick ones just spend them sooner. The carbon in that heart was forged inside a star that died before the sun existed. It has been, at various times, seawater and fern and something else's blood, and for this particular window it has organized itself into a thing that leans into me when it is frightened.
The technician was still waiting for an answer.
I said the animal was, at this instant, one of the most improbable arrangements of matter in the observable universe, and that its warmth was the sound of it refusing, cell by cell, to become ordinary again.
She wrote something down.
I don't think it was that.