What is Bergmann's rule?
Q: What is Bergmann's rule?
A: Bergmann's rule is an ecogeographic principle that states that animals within a widely distributed group tend to be larger in colder environments and smaller in warmer regions.
Q: Who discovered Bergmann's rule?
A: The rule is named after nineteenth-century German biologist Carl Bergmann, who described the pattern in 1847, although he was not the first to notice it.
Q: Does Bergmann's rule only apply to species or populations as well?
A: Although originally put in terms of species, Bergmann's rule seems to apply to populations within a species.
Q: Does Bergmann's rule apply only to mammals and birds?
A: Bergmann's rule is most often applied to mammals and birds which are endotherms but some researchers have also found evidence for the rule in studies of ectothermic species.
Q: Are there any exceptions to Bergmann's rule?
A: Yes, there are exceptions to Bergmann's rule, although it appears to hold true for many mammals and birds.
Q: Does Bergmann's rule only apply to living animals?
A: No, Bergmann's rule has been reported in extinct populations from the fossil record as well.
Q: Was there any dwarfing of mammals during extremely warm periods in the past?
A: Yes, reversible dwarfing of mammals happened during two extremely warm but brief times in the Palaeogene.
