Shrews Shrink Their Brains for Winter, Then Regrow Them
Shrews reduce brain size by about 30% in winter to conserve energy and regrow it in spring; new research traces the genetic basis of Dehnel's phenomenon, showing upregulated brain-formation genes, VEGFA, DNA repair and longevity pathways, and water-regulation changes that imply reversible brain-volume loss rather than neuron death—offering clues for neurodegenerative disease research.