Shape-shifting: changing animal morphologies as a response to climatic warming (vol 36, pg 1036, 2021)

Many animal appendages, such as avian beaks and mammalian ears, can be used to dissipate excess body heat. Allen's rule, wherein animals in warmer climates have larger appendages to facilitate more efficient heat exchange, reflects this. We find that there is widespread evidence of 'shape-shifting' (changes in appendage size) in endotherms in response to climate change and its associated climatic warming. We re-examine studies of morphological change over time within a thermoregulatory context, finding evidence that temperature can be a strong predictor of morphological change independently of, or combined with, other environmental changes. Last, we discuss how Allen's rule, the degree of temperature change, and other ecological factors facilitate morphological change and make predictions about what animals will show shape-shifting.

Automated summary

Animal appendages are used to dissipate excess body heat, with larger appendages facilitating more efficient heat exchange in warmer climates. Endotherms exhibit widespread evidence of 'shape-shifting' in response to climate change. Temperature is a strong predictor of morphological change independently or in combination with other environmental changes.