Researchers from the University of Alaska Fairbanks and the University of Reading has challenged the validity of Bergmann's rule, a long-standing scientific principle from the 1800s. Bergmann's rule proposes that animals in cooler, high-latitude climates tend to be larger than their counterparts in warmer climates. However, the fossil record examined in this study reveals a more complex picture.
Lauren Wilson, a UAF graduate student and lead author of the study published in Nature Communications, emphasized that the evolution of body sizes in dinosaurs and mammals cannot be solely attributed to latitude or temperature. Bergmann's rule, she argues, is only applicable to a subset of animals with stable body temperatures and only when temperature is considered in isolation from other climatic factors. This challenges the notion that Bergmann's rule is a universal principle.
The study originated from a question posed by Wilson and her undergraduate advisor: Does Bergmann's rule apply to dinosaurs? By analyzing extensive data from the fossil record, particularly focusing on dinosaurs in Alaska's Prince Creek Formation, the researchers found no significant increase in body size among Arctic dinosaurs despite harsh environmental conditions.
Expanding their analysis to modern mammals and birds, the descendants of prehistoric creatures, yielded similar results. Latitude did not consistently predict body size in these modern species, although a minor correlation was observed between modern bird size and temperature.
Jacob Gardner, a postdoctoral researcher at the University of Reading and co-author of the study, emphasized the importance of using the fossil record to challenge and test contemporary scientific rules and hypotheses. He highlighted how studying past ecosystems and climate conditions can offer new insights into the applicability of ecological rules.
Pat Druckenmiller, director of the University of Alaska Museum of the North and co-author of the paper, emphasized the necessity of considering evolutionary history to understand modern ecosystems fully. He stressed the importance of looking to the past to comprehend the origins of present-day ecological phenomena and species characteristics.
Source: University of Alaska Fairbanks