“Who can chill?”: Comparing metabolic rates between mice and cockroaches in cold temperatures

Abstract

Thermoregulation is an important survival function put in place by animals and it can be carried out in two specific ways. Ectotherms rely on outside sources of heat to regulate internal body temperature while endotherms maintain their body temperature by exerting energy they have created themselves. We are interested in the difference between these metabolic responses of endotherms and ectotherms in a cold environment. We hypothesized that mice would require more energy than cockroaches to maintain homeostasis in a cold environment. To test this, we measured the increase of CO2 amounts- another way to measure metabolic rates- in a chamber containing a mouse and at a separate time, 3 cockroaches. The chamber was cooled to an ambient temperature of 10 degrees Celsius and the animals were held in the chamber for 5 minutes. The mouse had a much higher rate of oxygen consumption than the cockroaches. Our results supported our hypothesis that internal heat regulation of the mouse requires a higher metabolic rate than external heat regulation of the cockroaches.