Mice have modified their habits and appearance as a result of climate change. This is the hypothesis of a Canadian study that compared new specimens with those that lived in the 1950s.
Global warming, and the milder winters that come with it, are the most likely cause of the physical and behavioural changes observed in two North American rodent species: the deer mouse and the white-footed mouse. This is the finding of a study conducted by a group of researchers at McGill University in Montreal, Canada.
Virginie Millien, who led the research, spent ten years studying specimens found in the university's nature reserve, which covers an area of one thousand hectares in the St. Lawrence Valley, roughly 40 kilometres east of Montreal. First and foremost, "milder winters have caused the white-footed mouse to shift northward at a rate of approximately 11 kilometres per year", reports 3Bmeteo.com. Furthermore, by comparing new specimens with samples collected since the 1950s, the researchers found changes in the skull shape and molar positioning of both species.
The different availability of food resources brought about by climate change and competition between the two species would have altered the mice's diet and, consequently, their physical characteristics. "One question that remains to be settled is whether the changes are genetic and will be passed on to future generations, or whether they instead represent plasticity — that is, the ability of certain species to adapt to rapid environmental changes," explains Carlo Migliore of 3Bmeteo.com.
Since 1950, the average annual temperature in Quebec has risen by approximately two degrees, and is set to increase by a further three degrees by 2050. The results obtained by McGill University add another piece to the body of research documenting the rapid response of wildlife to climate change. Mice represent an ideal subject, as they reproduce very quickly. Humans, however, could also evolve in response to environmental changes.