Metabolic Calculators: Mammals (Intraspecific)

Here are metabolic calculators for several common species of mammals, which predict metabolic rates on the basis of body mass. These are intraspecific allometries - in other words, they apply only to the designated species, not across different species. They are valid only for basal metabolic rates (the animal is post-absorptive, inactive and within its thermal neutral zone). Typical metabolic rates may be somewhat higher. Energy equivalents (Watts, Joules) assume an RQ of 0.83. Like all allometrically-based estimates of metabolic rates, the results are approximate, but should be close enough to real values to act as a reality check.

Flow rate suggestions are for typical flow-through respirometry and are also approximate. The highest usable flow rate is dependent on the quality of the O2 analyzer being used, which determines the lowest change in O2 concentration that can be reliably resolved. Examples of "superb" and "good" O2 analyzers can be found here and here, respectively. In general, a good flow rate to aim for is about 50% of the suggested maximum for the grade of analyzer you are using. The minimum flow rate corresponds to a 1.5% depletion of O2 in the excurrent air and should be exceeded by at least twofold if at all possible.

For our biomedical users: Please read our cautionary notes in the interspecific metabolic calculator. Note especially that the actual interspecific mass scaling of mice has a mass scaling exponent that is radically different from the exponent incorrectly assumed in standard, commercial metabolic screening systems! (0.91 vs. 0.75, which is actually an interspecific mass scaling exponent, and a discredited one at that). See Chapter 13 of my book. If you have questions, contact me.

Note that all metabolic calculator JavaScript code on this page is (c) John Lighton 2008. All rights are reserved. You are welcome to link to this page without restrictions, but copying and re-posting of the code is strictly prohibited. Suggestions for additional taxa and citations are welcome.

Mammalian Intraspecific Metabolic Rates

This section covers several common placental mammals. All options are only valid for body masses within the likely range of the selected taxon. Please use with care and consult the appropriate citation if you need more details.

Enter the body mass in grams:

Choose the taxon:

Choose the desired BMR units:

Give maximum flow rate suggestions for:

Click this button to calculate the BMR:

Estimated BMR is:

Citation is:

Approx. maximum flow rate (ml/min):

Approx. minimum flow rate (ml/min):