Why do mice have a higher metabolic rate than humans?

Question

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body?What is it in this cell that will be different? How is that regulated inside mouse cell?

Answer 1

Hi there,

We can think of this problem more simplistically:

An animals' surface A-to-V ratio will vary with its size; this can be related back to a small cell having more area (surface) relative to its overall volume when compared to a larger cell. A smaller animal will have more body surface area relative to the overall volume of metabolically active tissue. Animals will exchange heat with their environment over their overall body surfaces and in conjunction with the aforementioned explanation, this explains why smaller animals tend to lose heat to a relatively cooler environment faster than larger animals. This in turn accounts for why smaller animals have higher energetic requirements that satisfy higher metabolic rates and therefore help maintain constant internal/core temperatures, especially in environments where the temperatures are lower than the animals' internal/core body temperatures.

I hope this helps. Please let me know if you have any other questions.

-Dr D