Despite the joy of seeing a red squirrel up close, recent research suggests that feeding them may be harming the species.

The iconic rodent, once widespread in the UK, is now only found in a handful of woodlands. As breeding is limited within these isolated populations, changes to diet or habitat, or the introduction of disease can impact an entire population in just a few generations.

Analysis of over 250 skulls from different locations in the UK has shown significant changes to the jaws of red squirrels in Formby, Liverpool. Here, the usual diet of hazelnuts and pine seeds has often been supplemented with biscuits, chips and peanuts from humans.

These treats require much less chewing, which researchers say could have caused the changes to the squirrels’ masseters (cheek muscles) and made wild foods harder to consume.

Long term, the change in diet could affect trees that rely on these animals spreading seeds, along with the woodland species that depend on them.

Learn more about red squirrels:

Main image: A red squirrel at a feeder filled with nuts in an area of woodland in Scotland. © John F Scott/Getty


Amy Arthur is a freelance science and health writer.