Are black squirrels a separate species?

ABlack individuals of both the eastern grey (the invasive rodent now well established in Britain) and red squirrels are reasonably common. These are not distinct species, but melanistic forms. However, a study published earlier this year recognises the Calabrian black squirrel, endemic to that region of southern Italy and formerly considered a subspecies of the red squirrel, as a separate species, with the scientific name Sciurus meridionalis.

Researchers from the universities of Rome, Insubria, Calabria, Florence and Milan discovered that the Calabrian black squirrel has a recognisably different morphology. It is larger, with more prominent feet and a darker back and tail than the black form of the red squirrel. It also occurs in a different habitat, preferring mature pine forests in mountainous areas, and its mitochondrial DNA displays three distinct markers.

Unfortunately, this newly recognised species is already under threat. In the limited habitat it occupies, it faces competition from the invasive variable (or Finlayson’s) squirrel Callosciurus finlaysonii, introduced from Southeast Asia, which damages native Italian trees.

The Calabrian black squirrel occurs across some 7,000km2 of southern Italy. Like its red cousins, it is arboreal, preferring black pines.