Black squirrels have advantages and disadvantages, depending on where they areDoug Wechsler / naturepl.comRoad accidents seem to be behind the natural selection of black squirrels in US cities, as they may be easier than grey ones for motorists to spot and swerve to avoid.Grey squirrels (Sciurus carolinensis), known as eastern gray squirrels in the US, have been introduced in countries throughout the world, but their native range is eastern North America. Despite their name, theyhave actually evolved a variety of colours. The grey version is the most common, but there are also black forms and