Allen's rule


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Allen's rule

[′al·ənz ‚rül]
(vertebrate zoology)
The generalization that the protruding parts of a warm-blooded animal's body, such as the tail, ears, and limbs, are shorter in animals from cold parts of the species range than from warm parts.
References in periodicals archive ?
The research validates a 133-year-old ecological theory called Allen's rule, which predicts that animal appendages like limbs, ears, and tails are smaller in cold climates in order to minimize heat loss.
Dr Symonds said Allen's rule has never been tested with this large a group of animals and was more anecdotal.
Biologists have Bergman's and Allen's Rules, which predict reduced surface area to body size and shorter limbs in colder environments," says Higgins.