Shrews exhibit reversible size changes in their skulls and noses to get through the winter
Scientists had previously observed that some species of shrews undergo a form of biological plasticity in which their bodies, skulls, brains and some organs shrink in the winter, then regrow in the spring. Now, a new study in Japan, published in the Proceedings of the Royal Society B: Biological Sciences, has taken a closer look at this phenomenon and found that shrews' snouts exhibit an inverse…
Scientists have discovered that shrews undergo a unique form of biological plasticity, where their skulls, brains, and snouts shrink during winter and then regrow in the spring. This phenomenon, known as Dehnel's phenomenon, was first described in 1949. A recent study in Japan, published in the Proceedings of the Royal Society B: Biological Sciences, has provided new insights into this process, revealing that shrews exhibit a "reverse Dehnel's phenomenon" as well.
While their brains shrink in winter, shrews' snouts grow larger during this period before shrinking again in early spring. This reversal in snout size may be due to several factors, including improved dietary options, enhanced thermoregulation, or better olfactory detection in snowy conditions. The researchers propose that the reverse Dehnel's phenomenon is a sophisticated, region-specific process of cranial remodeling, likely an adaptive response to winter stress.
The study's findings highlight the modular and non-uniform nature of shrews' cranial changes, with potential implications for understanding the evolutionary mechanisms behind both Dehnel's and reverse Dehnel's phenomena.
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