Shrews remodel skull shapes to survive winter cold

New research led by Hokkaido University has revealed that shrews undergo complex skull remodeling to survive winter. While the phenomenon of seasonal shrinking, known as Dehnel’s phenomenon, has been observed in various small mammals like moles and voles for decades, scientists previously lacked a full understanding of the process.

By examining 136 long-clawed shrew specimens, researchers found that the skull does not merely decrease in size by approximately 20%, but actively remodels its shape. This biological adaptation helps the animals manage energetic challenges caused by extreme cold and food scarcity. In addition to the skull, these mammals may also shrink internal organs, including the heart, liver, and kidneys, to conserve energy.