Scientists who study mice in Quebec, Canada, have noticed something that environmentalists have been warning us for decades. The team noticed noticeable physical changes in the two species of mice in the study and fixed it on climate change.
According to the climate and climate website, there is already undeniable evidence that animals, birds and plants are being affected by climate change and global warming.
Now, a team led by Virginie Millien, an badociate professor at McGill's Redpath Museum, could have provided conclusive evidence of the same.
The team has been studying two similar species: the deer mouse and the white-legged mouse: for a decade at the Gault Nature Reserve at McGill University in Montérégie, Canada.
These common mouse species are found in eastern North America. The deer mouse is found further north, while the white-footed mouse is rarely found north of the St. Lawrence River on the mainland.
The team compared specimens that they found in the wild with a treasure trove of preserved specimens provided by the museum for researchers. These specimens date back to the 1950s and 1970s, giving the team a broad enough insight into the evolutionary timeline of mouse species to badyze permanent changes.
The team found that specimens collected from the field had a different skull shape in both species. They observed that the change was gradual and that both species were affected.
"It's an indirect effect, based on what they are feeding," Millien said in a press release on the official website of McGill University. She said that her diet modifies her jaw and this in turn affects the shape of her skulls. But, the team also calculated the rate of change in the shape of the skull and discovered that the skull shapes of the two species changed at different speeds. It was discovered that the change in the shape of the skull of the white-legged mouse is much more pronounced than that of the deer mouse.
The team is still not sure if the changes will continue after the reproduction, making these changes evolutionary and permanent. In any case, the physical changes, although difficult to discern for the untrained observers, are significant. "We're talking about bones and teeth, hard structures that are not easy to bend," Millien said.
At the same time, the white-legged mouse has moved northward as the winters become milder, at a rate of around 11 kilometers a year, the researchers estimate.
During the collection of specimens in the 1970s, almost 90 percent of the mice in the reserve were deer mice. Today, the species of white legs is by far the most abundant. As the stag mouse decreases in abundance in the southern regions, Millien said it could also be shifting to the north.
"The two mice are similar and compete with each other for nesting sites, for food, for everything, if you have an established population, here, the deer mice, and a new species enters and is in aggressive colonizer mode, It takes over, "he said.
"One way to reduce competition is to become clearer, so there is less overlap in the type of food you use, which has been documented in birds: it's called character displacement. happening here, the two species are more different than they used to be, "he added.
The team believes that both the physical changes observed in the skull and the change in population estimates show that climate change is the common factor.  "The common driver, we believe, is climate warming, and the very common response to climate warming is for species to change to the north," he added.
The findings were published in the journal Evolutionary Ecology.