Over more than a century, chipmunk and vole skulls have changed shape to fit an urban lifestyle
Chipmunks in the Chicago area have developed larger skulls with shorter teeth on the sides of their mouths, while parts of voles’ inner ears have shrunk. Through looking at specimens housed at Chicago’s Field Museum, scientists found evidence of fast-paced city evolution linked to urbanization in the rodents. Researchers took measurements and created 3D scans of the skulls, comparing how their size and shape changed over 125 years. Researchers think that changing diets caused the shifts in the eastern chipmunk (Tamias striatus) skulls. The chipmunks became larger because they were eating more human food. They had smaller teeth because they were eating fewer hard foods, like seeds and nuts. The eastern meadow voles (Microtus pennsylvanicus) had smaller bones in the inner ear associated with hearing, potentially to help them deal with noise pollution. “These findings clearly show that interfering with the environment has a detectable effect on wildlife,” said Anderson Feijó, assistant curator of mammals at the Field Museum and co-author of the study, in an interview with the museum.
Read more at Integrative and Comparative Biology.
