Feeding peanuts to red squirrels may be altering the development of their jaws.
October 18, 2022
Feeding peanuts to red squirrels may be altering the development of their jaws.
A population of the endangered rodents living in Formby, Merseyside, have uniquely shaped lower jaws, possibly as the result of being fed softer foods. While the activity is now discouraged, the practice appears to have left a legacy in these squirrels, among the last to be living in mainland England.
While it is currently unclear if the changes in jaw structure are a result of evolution, or adaptations during its lifetime, the ability of researchers to track the changes is an indication of how isolated the squirrels are becoming.
Kim Chandler, a Ph.D. student at the University of York, is conducting research into how red squirrels are changing as a result of their diet.
„I don’t think these kinds of changes would have been observed if red squirrel populations were larger,“ Kim explains. „Without genetic mixing between them, British populations have become very isolated from one another.“
„This means that populations in northern Scotland, Formby and elsewhere are effectively acting as their own evolutionary islands.“
Why are red squirrels declining?
Wind back the clock 150 years, and red squirrels would have lived in forests all over the country, as well as in outposts such as Jersey in the Channel Islands.
However, this all began to change in the late nineteenth century. Some of the earliest gray squirrels were introduced to Henbury, Cheshire in 1876, followed by further introductions in Bushey, Hertfordshire and Woburn, Bedfordshire over the following years.
These introductions were primarily for ornamental reasons, with North American gray squirrels released on private estates by wealthy landowners. As the rodents breed more quickly than their native counterparts, the gray squirrels soon began to spread beyond these boundaries of these estates and across the country.
