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Bergmann’s Rule
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Bergmann’s Rule

zoology
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History

Bergmann’s Rule, in zoology, principle correlating external temperature and the ratio of body surface to weight in warm-blooded animals. Birds and mammals in cold regions have been observed to be bulkier than individuals of the same species in warm regions. The principle was proposed by Carl Bergmann, a 19th-century German biologist, to account for an adaptive mechanism to conserve or to radiate body heat, depending on climate.