Scientists have discovered a surprising way in which long-clawed shrews in Japan may adapt to harsh winter conditions. During the cold months, the animals’ snouts become larger, while their brains and skulls become smaller.
The finding is unusual because researchers expected the animals to reduce the size of their body parts during winter to save energy. Instead, the shrews appear to follow a different pattern with their noses.
The study provides new information about a natural process called Dehnel’s phenomenon. This is a seasonal change seen in some small mammals, especially shrews. During winter, their bodies and some organs become smaller. This helps them use less energy when food is harder to find.
Researchers already knew that the brains and skulls of some shrews become smaller during winter. However, the new study found that the snouts of long-clawed shrews can become up to 7% larger in both height and width.
Yugo Ikeda and his research team studied 136 shrew skulls collected in Hokkaido, Japan, between 1948 and 1988. They carefully measured different parts of the skulls and compared the measurements with the seasons in which the animals had been found.
The researchers expected to see smaller skulls and brains during the winter months. While they found the expected changes, they also noticed something unexpected—the shrews’ snouts became larger during winter.
When spring arrived, the snouts returned to their normal size. This shows that the change is seasonal and may be connected to the animals’ need to survive cold conditions.
Scientists are still trying to understand why the shrews develop larger snouts during winter. One possibility is that the change may help the animals find food or deal with cold weather more effectively. However, more research is needed to understand the exact reason.
The discovery challenges some earlier ideas about how small mammals adapt to extreme environments. It also shows that animals can develop unusual physical changes to survive difficult conditions.
The study gives scientists a better understanding of Dehnel’s phenomenon and the survival strategies of shrews. It also suggests that there may be many other seasonal adaptations in small animals that have not yet been discovered.
For such a tiny animal, the long-clawed shrew has shown a remarkable ability to adjust its body to the changing seasons. Further research may reveal more about how these animals survive Japan’s harsh winters.