The common shrew, a slight mammal found throughout Northern Europe, possesses a remarkable ability to adapt to harsh winter conditions by dramatically shrinking its body size, including its brain and bones. This adaptation, detailed in recent research, highlights the extraordinary resilience of wildlife and raises potential implications for medical science.
Researchers have long known that shrews undergo significant physiological changes during the winter months when food is scarce. A study published in September 2024, identified over 190 species of viruses in 32 genera found in shrews, underscoring their role as potential reservoirs for zoonotic diseases. The common shrew (Sorex araneus), also known as the Eurasian shrew, typically measures 55 to 82 millimeters in length and weighs between 5 and 12 grams. It is one of the few venomous mammals.
The shrinking process isn’t simply a matter of cell death. Scientists have discovered that shrew cells decrease in size without dying, effectively halting programmed cell death – a process that triggers cell destruction. This mechanism, as reported in the journal Viruses, could potentially inspire new treatments for neurological diseases in humans. Except for their sense of smell, shrews maintain nearly the same cognitive function in winter as they do in summer, despite the reduction in brain mass.
The ability of shrews to shrink and regrow tissues is particularly relevant in the context of emerging infectious diseases. The Helmholtz Institute for One Health is conducting research in Taï National Park, Côte d’Ivoire, to understand the transmission pathways of viruses and other pathogens between animals and humans. Their perform has revealed that squirrels act as a reservoir host for the Mpox pathogen, which can then be transmitted to apes.
This research emphasizes the “One Health” approach, which recognizes the interconnectedness of human, animal, and environmental health. Preventing spillover events – the transmission of pathogens from animals to humans – requires collaboration across scientific disciplines to identify risks and interrupt infection chains. The One Health project in Côte d’Ivoire is intended to serve as a model for other regions globally.
While shrews demonstrate an extraordinary ability to adapt, other animals possess unique traits that humans cannot replicate. Birds, for example, are capable of flight due to their ultra-light skeletons, efficient respiratory systems, and specialized feathers. Humans, lacking these evolved characteristics, can only approximate flight with the aid of technology.
The intelligence of animals is also increasingly recognized. In Frankfurt, Germany, a crow has formed a unique bond with a hospital employee, recognizing him and visiting his window daily for nuts. Ornithologist Bernd Petry explains that crows are capable of recognizing individual human faces and forming lasting social connections, suggesting a level of cognitive ability previously underestimated.
