City shrews have bigger personalities

A new study from the University of Lisbon reveals that urbanization impacts the personalities of individual shrews. The greater white-toothed shrew is expanding its range in Europe and has been identified as invasive on some islands in Ireland. In order to predict where else shrews may emerge, it is important to understand how these small mammals adapt so rapidly to new environments.

“Urban environments differ in many aspects from natural or rural ones and thus pose challenges for many animal species. Some of these challenges have been connected to the observation that urban individuals of many animal taxa are bolder and more aggressive than their rural conspecifics,” wrote the study authors. 

“Apart from average behavioral differences between rural and urban populations, the variation of such behaviours within these populations may differ, enabling them to deal with the spatially and temporally heterogeneous habitats within cities. Here we tested average differences in behavior as well as the components of variation in these behaviors in rural and urban populations of shrews.”

Beyond confirming that urban shrews are more active and aggressive, the researchers have discovered that shrews from urban environments differ more in their individual behavior than those in rural environments.

“Possibly, such diverse city personalities are caused by the high spatial and temporal heterogeneity in urban environments,” explained study first author Sophie von Merten.

The shrews that were observed for the study came from a diverse assortment of sites, ranging from small patches of vegetation on a busy university campus to city parks or green spaces located next to a noisy highway. Furthermore, the same results were found in two different species of shrews: the greater white-toothed shrew and the common shrew.

“The fact that similar results were found in two species that are so different to each other hints at a general pattern,” said study co-author Professor Leszek Rychlik. “As cities are continuously growing around the globe, studies like ours are important to better understand of the consequences of urbanization on wild animals. Ultimately this might help us to protect biodiversity.”

The study is published in the journal Animal Behaviour.

Image Credit: Ana Cerveira

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By Chrissy Sexton, Earth.com Staff Writer