The newly published studies of the biology professor UNC Greensboro, Dr. Bryan McLean and colleagues, show that a masked malicious, small mammal much like a mole found in the Appalachów mountains, reduces his body and brain to maintain energy in the winter months.
The study, published in the problem of May 2025, showed that masked shrew () reduces body weight by 13 percent in cooler months; Then the creation grows in spring when the conditions improve. In addition to the shrinking body, the team also found seasonal changes in the peak of the creation (a part of the skull that houses and protects the brain) and the length of the femur.
“Reduction of the body and its parts is actually a clever strategy of survival,” says McLean. “And this is important to us to understand, because mammals stand in a constantly changing planet.”
This seasonal shrinking, referred to as the phenomenon of Dehnel, was observed in other mammals, but most frequently in the malice, that are small, eating insects, animals not related to rodents. The phenomenon of Dehnel is an extreme example of “phenotypical plasticity” – the body’s ability to vary its physical form in response to environmental changes.
“We do not know how the common phenomenon of Dehnel is among mammals, but we know that it has a rarer nature than other energy-saving strategies, such as hibernation,” said McLean.
McLean and his team of graduates and students analyzed 125 masked textbooks, which were imprisoned in the National Forests in Pisga, North Carolina in 2021–2023. The team used “traps traps” buried in the rubbish to capture Shrews. Animals were weighed in the sector, after which dropped at the joint school of Nanonuki UNCG and nanotechnology to look at various skeletal dimensions. Samples and related data are archived in the UNCG mammalian collection. Researchers from Georgia Southern University were also involved in research.
“Our population of masked Shrews is the most important, but studied for these many different features,” said McLean, “and the femoral measurements, which we were the first to make, which showed the size of a seasonal change in long bones of the skeleton. This shows that the rapid reconstruction of a significant part of the skeleton.”
Most of the previous studies of this phenomenon come from Europe. To put their recent results in the context, scientists also conducted a meta -analysis of 74 other studies from all the northern hemisphere, combining these studies with their very own discoveries to grasp what aspects drive the phenomenon of Dehnel. McLean and his team developed statistical models that accurately predicted the degree of body contraction, which they observed only on the premise of the climate in the place of North Carolina.
“This analysis reveals the generality of the phenomenon of Dehnel in Shrews,” explains McLean. “In many populations of Bajgań on three continents, the degree of body weight and brain height contraction is the highest in areas with the lowest temperatures of the cool season. So the fall and winter temperatures predict the phenomenon of Dehnel in these animals.”
“Phenotypical plasticity is a key way in which the bus and many other species react to temperature changes,” notes McLean. “By learning more about this process, we can start understanding how mammals buffer against a rapidly changing climate.”
