How the grey squirrel drove out the red… it’s smarter

THEY are bigger and tougher than their red cousins.

But that may not be what has made grey squirrels the dominant breed. They also happen to be smarter, and it is this which scientists think gives them the edge.

According to researchers, the greys are better at problem solving. Given a task involving pushing and pulling levers to get hazelnuts, 91 per cent of greys were able to work it out, compared to 62 per cent of reds.

The findings suggest greys, which came here from North America in the 19th century, may be more adaptable than the reds – which they now outnumber by more than 15 to one.

Dr Pizza Ka Yee Chow, from the University of Exeter, which led the study, said: ‘Many factors have been considered to explain why grey squirrels are more successful. These include disease resistance and the fact greys are bigger, but our research shows problem-solving could be another key factor.

‘This might be especially important for an invasive species, as they have to adapt to their surroundings.’

The researchers, from the universities of Exeter and Edinburgh, tested grey squirrels in Exeter and reds on the Isle of Arran, off the west coast of Scotland. The greys were better at the most tricky task to obtain hazelnuts. The study, published in the journal Animal Behaviour, said the greys’ flexible skills ‘may have facilitated their invasion success’.