Red squirrels fed on peanuts by well-meaning environmentalists on the Merseyside coast may have lost the ability to consume their traditional diet of tougher pine cone seeds, hazelnuts and beech nuts, researchers in York say.
A study found the squirrels at Formby had developed in a different way to other populations of the rare species in England, with changes to their jaws and bite strength brought about by their softer diets
“It’s really surprising, said Dr Philip Cox at the University of York. “I wasn’t looking for a change in particular population of squirrels.
“We used to have red squirrels across the country. Now we don’t have so many and everyone knows and loves them – it’s a big conservation story.
“But they’re isolated, and I wondered if they might be evolving in different ways, because of the local conditions. But I hadn’t really thought that any differences would be quite so pronounced.”
He said the changes to the animals’ bone structure was comparable to that of humans whose muscles were prone to weakening if they were not used.
“It could be that if squirrels are not using their jaws as much, they are becoming less efficient.
“This may have happened in their lifetime or over a number of generations,” he said, adding that if the squirrels at Formby, a population managed by the National Trust, were released into other unmanaged woodland colonies to encourage breeding, they might struggle to survive.
“Efforts to conserve the red squirrel population at Formby have been really successful, but there may have been an unsuspected impact,” he added.