“The appendages have an important but often underestimated role in animal thermoregulation as places of heat exchange”, details the research published in the journal Trends in Ecology and Evolution .
Many animals occupy parts of their body, such as bird beaks and mammalian ears, to dissipate excess body heat. The researchers note that this is explained in Allen’s rule, which states that animals in warmer climates have larger appendages to facilitate more efficient heat exchange.
“We found that there is widespread evidence of ‘shape change’ in endotherms in response to climate change and its associated climate warming,” they note.
Experts also point out that this could result in the relaxation of natural selection for small appendages through which body heat could be detrimentally lost in cold climates.
What species will change shape and why?
While much evidence seems to indicate that the size of the appendages is changing, there are differences in the strength of those changes and in how they affect animal function. Changes can be limited to what is feasible within the constraints of phylogenetic history (a discipline of evolutionary biology concerned with understanding the historical relationships between different groups), developmental biology, and ecology.
In fact, a broad analysis of the evolution of peak shapes reveals that their shape is highly dependent on trade-offs between various functions and behaviors, which may therefore include a thermoregulatory function.