Grey squirrels have driven out Britain’s native reds, and most Britons think it’s because they are bigger and bullies.
However it is not their brawn that has given them the edge, but their brains.
A study has found grey squirrels may out-compete British red squirrels because they are better at problem-solving.
Both species were equally successful at the easy task, which involved opening a transparent lid to reach the hazelnuts. But grey squirrels were better at the trickier task, trying more times and in shorter bursts (file photo)
Giving a task involving pushing and pulling levers to get hazelnuts, 91 per cent of greys were able to figure it out, compared to just 62 per cent of reds.
The findings suggest grey squirrels, 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 when they move into areas where red squirrels live.
The findings suggest grey squirrels, 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 (file photo)
‘These factors include disease resistance and the fact grey squirrels are bigger, but our research shows problem-solving could be another key factor for the success of greys.
‘This might be especially important for an invasive species like grey squirrels, as they have evolved elsewhere and have to adapt to their surroundings.’ The researchers tested grey squirrels in Exeter and red squirrels on the Isle of Arran, off the west coast of Scotland, on two separate tasks.
Both species were equally successful at the easy task, which involved opening a transparent lid to reach the hazelnuts. But grey squirrels were better at the trickier task, trying more times and in shorter bursts.
The greys most often discovered the correct strategy of pushing the near end and pulling the far end of a lever, although red squirrels were quicker to change tactics.
A study has found grey squirrels may out-compete British red squirrels because they are better at problem-solving (file photo)
Previous evidence suggests grey squirrels also have greater spatial memory than red squirrels, which allows them to remember where their nuts are buried.
On the latest results, researchers from the universities of Exeter and Edinburgh said their flexible skills ‘may have facilitated their invasion success’.
Since being introduced to the UK and Ireland in the 19th century, and Italy more recently, grey squirrel populations have exploded to replace red squirrels. There are more than three million greys in the UK, while just 30,000 of their red cousins remain in England, 120,000 in Scotland and around 1,500 in Wales.
‘It is not yet clear whether grey squirrels are born better problem-solvers, or whether they work harder because they’re an invasive species living outside their natural environment,’ Dr Chow said.
‘The current stage of our research is to look at this, and the results may give us more insight into the likely future of both species.’ Professor Stephen Lea, also from Exeter’s Centre for Research in Animal Behaviour, said: ‘These results illustrate how investigating animals’ differing cognitive abilities can help us understand important issues in conservation.’ The study is published in the journal Animal Behaviour.