The gray squirrel is more adaptable than the red squirrel.
At one time the gray squirrel lived only in North America. Its exportation to Britain by the Victorians has had an effect of the survival of the red squirrel, a European native.
Red Squirrels
The red squirrel (Sciurus vulgaris) is native to Europe and Asia. Their population is declining in Britain, where hunting, disease and forest management through the years have affected their numbers.
Gray Squirrels
The gray squirrel (Sciurus carolinensis) is native to the northeastern part of North America. They were first introduced to Britain in 1876, and have thrived, says Squirrels.Info, a website dedicated to British squirrels.
Size
The gray squirrel, which can reach almost 2 feet long including the tail, is larger than the red squirrel, at 18 inches long. British gray squirrels on average weigh 19 1/2 oz., while red squirrels in Britain generally weigh 7 to 10 1/2 oz.
Activity
Gray squirrels spend more time foraging on the ground, and are adventurous. In contrast, the red squirrel is usually high in an evergreen tree, so its diet is more restricted.
Diet
One reason suggested for the increase of the gray squirrel in Britain, while the red squirrel declines, is diet. Gray squirrels are more adaptable and able to eat foods that are not digestible, or even toxic, to the red squirrel, according to Wildlife Online.
Tags: gray squirrel, more adaptable, North America, squirrel Sciurus, than squirrel