Despite the joy of seeing a rare red squirrel up close, you must resist the temptation to give them a snack, experts have warned.
Researchers have discovered that giving the species titbits that are softer than their natural diet may be changing their jaw shape and weakening their bite.
Normally, red squirrels chomp on hard food such as hazelnuts, pine seeds, acorns and even tree bark.
But during the 1990s conservationists provided a local population of red squirrels in Formby, Merseyside, with a steady supply of peanuts.
These softer nuts were given in such abundance that they made up more than 50 per cent of the squirrels’ diet, on average, in the area.
It is also thought that over the last few decades, visitors to the area have regularly provided the species with biscuits and chips to nibble on.
These treats require much less chewing and comparison with historic skeletons reveals a change in skull and jaw shape – suggesting that squirrels have a lower bite force after having their natural diet supplemented.
The researchers, from University College London (UCL), warned that care should be taken when providing food for wild – and captive – animals, so as not to influence their ability to consume their natural diet.
In recent years the National Trust has been communicating with visitors to the area that giving the squirrels extra food is unnecessary.
Despite the joy of seeing a rare red squirrel up close, you must resist the temptation to give them a snack, experts have warned
Researchers have discovered that giving the species titbits that are softer than their natural diet may be changing their jaw shape and weakening their bite
Comparison with historic skeletons reveals a change in skull and jaw shape – suggesting that squirrels have a lower bite force after having their natural diet supplemented
Writing in the journal Royal Society Open Science the scientists said: ‘Peanuts are less mechanically demanding than most other food items exploited by red squirrels, as their shells can be broken through with a much lower force than that needed to fracture hazelnut shells or to remove the scales from conifer cones.
‘We propose that these morphological changes are related to the reduced mechanical effort needed to process peanuts relative to naturally occurring food items.
‘This effect was partially reversed following a reduction in supplementary feeding of peanuts.’
They added that their findings have an ‘interesting parallel’ in modern humans, as it has been suggested that the modern soft diet has led to jaw shrinkage and dental overcrowding.
Red squirrels, once widespread in the UK, have seen their numbers severely decline since the introduction of the invasive grey squirrel.
Now, they are only found in a handful of woodland and are outnumbered 10 to one by the grey species, which were introduced to the UK from America around 150 years ago.
