Dinosaurs Challenge This Scientific Principle

A recent study challenges the Bergmann's rule, a 19th-century scientific principle stating that animals living in colder climates and at higher latitudes tend to be larger than their closer relatives residing in warmer climates.

This study, conducted by scientists from the University of Alaska Fairbanks and the University of Reading, reveals that the evolution of body sizes in dinosaurs and mammals cannot solely be attributed to latitude or temperature.


Lauren Wilson, a graduate student at UAF and one of the study's lead authors, pointed out that Bergmann's rule only applies to a subgroup of homeothermic animals (those maintaining a stable body temperature), and does so by only considering temperature while neglecting other climate variables. This suggests that Bergmann's rule is more the exception rather than the norm.

The study began with a simple question about the application of Bergmann's rule to dinosaurs. After examining hundreds of pieces of data from the fossil record, the answer was clearly negative. The researchers included in their data set the northernmost dinosaurs known, found in the Prince Creek Formation in Alaska, which lived in conditions of freezing and snowfall. Despite this, they found no notable increase in body size among these Arctic dinosaurs.

When applying the same assessment to modern mammals and birds, descendants of prehistoric mammals and dinosaurs, the results were similar: latitude did not predict body size in modern bird and mammal species. There was a slight correlation between the body size of modern birds and temperature, but this did not apply to prehistoric birds.

This research emphasizes the importance of using the fossil record to test current scientific rules and hypotheses, highlighting that modern ecosystems cannot be fully understood without considering their evolutionary roots.