Bergmann's rule

American  

noun

1. Zoology. the generally observed tendency for warm-blooded animals living in a cold climate to have a larger body size than animals of the same species living in a warm climate. Compare Allen's rule.

---

Bergmann's rule Scientific  

/ bûrg′mənz /

1. The principle holding that in a warm-blooded animal species having distinct geographic populations, the body size of animals living in cold climates tends to be larger than in animals of the same species living in warm climates. Animals with larger bodies are generally more massive and thus produce more body heat. They also have smaller surface areas relative to their mass, resulting in a relatively lower rate of heat radiation. The Bergmann rule is named for the German biologist Karl Bergmann (1814–65).

2. Compare Allen's rule

---

Example Sentences

The study started as a simple question Wilson discussed with her undergraduate advisor: Does Bergmann's rule apply to dinosaurs?

From Science Daily • Apr. 5, 2024

The researchers suggest that revealing a genetic basis for Bergmann's rule helps us to understand how evolution, natural selection and climate have interacted throughout a species' history.

From Science Daily • Nov. 7, 2023

By characterizing these candidates, they identified eight specific genetic variants closely linked to body mass -- aligning with Bergmann's rule.

From Science Daily • Nov. 7, 2023

"However, the genetic mechanisms underlying Bergmann's rule have remained elusive until now."

From Science Daily • Nov. 7, 2023

The evolutionary principle called Bergmann’s rule suggests that body sizes tend to be bigger in colder climates.

From New York Times • Jul. 28, 2014