Rodent of the Week: Mice try on a new look

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Evolutionary changes to the size and shape of humans certainly don’t take place rapidly. But others in the animal kingdom may be changing much faster.

A study today in the journal PLoS One found that the head shape and overall size of rodents has been changing over the last century. The changes appear to be linked to human population density and climate change.


Oliver Pergams, an ecologist at the University of Illinois, Chicago, initially found evidence that deer mice from the Channel Islands and white-footed mice in northwest Chicago had changed rapidly. He then looked at a collection of more than 7,000 body and skull measurements from rodents from all over the world. The collections are housed at Chicago’s Field Museum and the Smithsonian in Washington. He found both increases and decreases in 15 anatomic traits, with changes as great as 50% occurring over 80 years. Many of the traits were associated with changes in human population density, temperatures or trends in precipitation.

‘Rapid change, contrary to previous opinion, really seems to be happening quite frequently in a number of locations around the world,’ Pergams said. ‘Species can adapt quickly to environmental changes -- quicker than many people have thought, especially for mammals.’

It’s important to understand which species have the ability to change in order to conserve biodiversity, he said.

-- Shari Roan