Allen's rule

proper noun

An ecogeographic principle broadly stating that animals adapted to cold climates have relatively short limbs. Specifically, homeothermic animals in hot climates have low volume-to-surface ratios, and homeothermic animals in cold climates have high volume-to-surface ratios, due to thermal adaptation.

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Meanings

proper noun
  1. An ecogeographic principle broadly stating that animals adapted to cold climates have relatively short limbs. Specifically, homeothermic animals in hot climates have low volume-to-surface ratios, and homeothermic animals in cold climates have high volume-to-surface ratios, due to thermal adaptation.

Origin

Formulated by Joel Asaph Allen in 1877.

Full word history & related roots →
Cite this entry
APA

Allen's rule. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/Allen's%20rule

MLA

“Allen's rule.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Allen's%20rule. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “Allen's rule,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/Allen's%20rule.

Source: Allen's rule on Wiktionary, CC BY-SA 4.0.