By MATTHEW ROZSA
career helps illustrate why. The 19th century scientist traveled from the Dakota Territory to Brazil in order to collect specimens. When his health made further expeditions impossible, he established himself as a top researcher and writer, even helping to found the American Ornithologists’ Union (now part of the American Ornithological Society). He later became the first curator of birds and mammals at the American Museum of Natural History and, eventually, the first head of its Department on Ornithology.
He also figured out an important biological rule about homeothermic (previously known as warm-blooded) animals, one that is becoming tragically relevant as climate change alters the planet. Known as Allen’s rule, it holds that, generally speaking, animals’ appendages evolve to increase in size as the temperature around them also increases.Advertisement:https://1c3880c1389e354542a24baa7f9da043.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
According to a recent paper published in the journal “Trends in Ecology & Evolution,” Allen’s rule is manifesting itself in a number of animals because of climate change. In other words, animals’ bodies are adapting and changing in response to heat.
As the study’s coauthors write, “there is widespread evidence of ‘shape-shifting’ (changes in appendage size) in endotherms in response to climate change and its associated climatic warming.” This was seen in animals ranging from the great roundleaf bat, which saw an increase in the size of its wings, to wood mice, whose ears increased in length.