Bergmann's Rule Definition

bûrgmənz

noun

The principle that in wide-ranging, warm-blooded animal species, individuals living in a cold climate tend to be larger than individuals of that same species living in a warm climate.

American Heritage Medicine

The ecogeographic principle that, within a broadly distributed taxonomic clade, populations and species of larger size are found in colder environments, and species of smaller size are found in warmer regions.

Wiktionary

Origin of Bergmann's Rule

After Carl Bergmann (1814–1865), German biologist

From American Heritage Dictionary of the English Language, 5th Edition
Named after Carl Bergmann, nineteenth-century German biologist.

From Wiktionary