What are Bergmann’s and Allen’s rules? Bergmann's rule is one | Ask Me
What are Bergmann’s and Allen’s rules?
Bergmann's rule is one of the best-known generalizations in zoology.
It is generally defined as a within-species tendency in warm-blooded animals to have increasing body size with increasing latitude and decreasing ambient temperature.
Bergmann's rule states that among mammals and birds, individuals of a particular species in colder areas tend to have greater body mass than individuals in warmer areas.
This principle is named after a nineteenth-century German biologist, Karl Bergmann (1814-1865, on the left), who published observations along these lines in 1847.
A corollary of Bergmann's rule is Allen's rule, observed in 1877 by Joel Asaph Allen (1838-1921, on the right) which indicates a trend in terms of appendages of warm-blooded animals according to latitude. Allen's rule holds that individuals in populations of the same species have a tendency to have shorter limbs than the corresponding animals in warmer climates.
