Comment—Bergmann's rule is invalid: a reply to V. Geist

In a previous note, Geist attempts to prove that Bergmann's rule lacks both an empirical and a theoretical basis, and hence should be discarded (V. Geist. 1987. Can. J. Zool. 65: 1035–1038). It is noted that Geist has made a number of errors in interpreting the data and the theoretical material relating to the rule, and Searcy's arguments in particular have been distorted. It is concluded that Geist has confounded his data set with unrecognized multiple causality, a lack of critical analysis of biological relevance, inadequate partitioning of the data set, and misinterpretation of a physiological relationship. The conclusion that Geist has not proved Bergmann's rule to be invalid is justified.