Very much
unlike humans and rats (or anything larger than a mouse), mice enter a
state of torpor in the face of low food supply and / or cold temperature.
Torpor is when mice lower their metabolic rate immensely to conserve on
metabolic stores (like fat). The result is a tremendous drop in body temperature,
from 37° C (just like humans) to 1-2° C above ambient temperature.
See the temperature profile of an animal in torpor below. Blood pressure
and heart rate fall drastically in this evolutionarily conserved response
to low food supply.
Data were obtained during the night, their active period.
Normal
Mouse
Average systolic pressure =
125 mmHg
Average diastolic pressure =
90 mmHg
Average mean pressure =
111 mmHg
Heart rate = 580 beats per minute
Mouse
in Torpor
Average systolic pressure =
82 mmHg
Average diastolic pressure =
58 mmHg
Average mean pressure =
70 mmHg
Heart rate = 180 beats per minute
