Abstract
- Global climate change affects many aspects of biology and has been
shown to cause body size changes in animals. However, suitable
datasets allowing the analysis of long-term relationships between body
size and climate are rare.
- The size of the skull, often used as a proxy for body size, does not
change much in fully grown vertebrates, but some soricine shrews
shrink their skull and brain in winter and regrow it in spring. This
is thought to be a winter adaptation in these high-metabolic,
nonhibernating animals, as a smaller brain size reduces energy
requirements.
- Climate could thus affect not only the overall size but also the
pattern of the size change, i.e., Dehnel’s Phenomenon, in these
shrews.
- We assessed the impact of the changes in climate on the overall skull
size and the different stages of Dehnel’s phenomenon in skulls of the
common shrew, Sorex araneus , collected over 50 years in the
Białowieża Forest, NE Poland.
- Overall skull size decreased, along with increasing temperatures and
decreasing soil moisture, which determined the availability of the
shrews’ main food source, earthworms. The magnitude of Dehnel’s
phenomenon increased over time, indicating an increasing selection
pressure on animals in winter. Overall, climate clearly affected the
common shrew’s overall size as well as its seasonal size changes. With
the current acceleration in climate change, the effects on the
distribution range of this cold-adapted species may be quite severe.
Key words: body size, skull size, climate change, Dehnel’s
phenomenon, shrews