In preparation for winter, animals like bears stockpile fat while reducing their metabolism. However, a small mammal called the Eurasian common shrew has evolved a unique strategy to survive harsh weather conditions.
This phenomenon, named “Dehnel’s phenomenon,” allows the 5-12 gram shrew to shed up to 18% of its weight, including a significant portion of its brain mass, by shrinking its fuel-chugging organs. This adaptation enables the shrew to conserve energy and survive the winter.
Researchers from the US, Germany, and Denmark have identified genes responsible for this phenomenon in the shrew’s hypothalamus, which plays a crucial role in regulating metabolism. The findings are significant because they reveal intriguing links with genetic changes in humans implicated in Alzheimer’s disease.
The study compared gene expressions in the shrew’s hypothalamus to those of 15 other species, including rodents and primates. By analyzing these genes, the researchers found a suite of genes involved in energy homeostasis and cell death that may be associated with reduced brain size.
One sequence, BCL2L1, was identified as playing a role in managing cellular destruction. This discovery suggests that shrews’ brains undergo pruning to conserve resources during winter. The findings provide valuable insights into the diagnosis and treatment of cognitive decline in humans.
The study’s lead scientist notes that while this adaptation is beneficial for shrews, similar changes in humans would have severe consequences. Ongoing research suggests a significant overlap between metabolic disorders and neurodegenerative diseases, making further investigation into this phenomenon promising.
Source: https://www.sciencealert.com/this-animal-can-shrink-its-brain-and-we-finally-know-how