Hot Or Not? Size Does Matter in Animals' Ability to Thermoregulate

Sydney Liddell, Brooke Lorna King, Blake Kirk, Michael Cobbs


After reviewing an experiment testing Bergmann’s Rule, we decided to test its validity.  Bergmann’s rule states that within the same species of warm-blooded vertebrates, individuals from cold climates are usually larger in size than those from hot ones (Meiri & Dayann, 2003). Bergmann’s rule is generally interpreted to mean that larger animals are better suited for cold climates because of their lower SA/V ratios (James, 1970).  In this experiment, we test whether larger animals are better suited for thermoregulation in colder climates by conducting an experiment including recording the cooling rate of the internal temperature of 3 different-sized spheres submerged in an ice bath. Using a temperature probe to record the rates, we observed that the results supported the statements in Bergmann’s rule.

Full Text:



Bulard, B., J. Ball, L. Caldwell, L. Cash, M. Cobbs. 2014. Heat Retention vs. Shape: Using Clay Models to Test if Surface Area to Volume Ratios Truly Makes a Difference in the Heat Retention. Journal of Introductory Biology Investigations. 1.1: 1-3.

Donald P. French.2014. Investigating Biology, 2014.Fountain Head Press, Southlake,Texas.

Frances C. James. 1970. Geographic Size Variation in Birds and Its Relationship to Climate. Ecological Society of America. Volume 51 (3): PG 365-390.

Hoefnagel, M. 2015. Biology Concepts and Investigations, Third Edition. New York.

R. L. Nudds; and S.A. Oswald. 2007. An Interspecific Test of Allen’s Rule: Evolutionary Implications for Endothermic Species. Evolution. 61-12: 2839-2848.

Shai Meiri; and Tamar Dayan. 2003. On the Validity of Bergmann’s Rule. Jounal of Biogeography. 30: 331-351.


  • There are currently no refbacks.