What this actually means for the structure of the foot is a question that is still being researched today. It would seem that an accessory navicular is commonly related to pes planus. Frederick Kidner, in 1929, first theorized that the presence of an accessory navicular could be the cause of pes planus.
Successful as they are, Eastern Gray Squirrels live only 11-12 months on average, but some individuals have survived more than ten years in the wild. Factors affecting survival include the severity of winter, abundance of food, and parasites.
Sciurius carolinensis. The Eastern Gray Squirrel is a tree squirrel native to the eastern and midwestern United States and to the southerly portions of the eastern provinces of Canada. A prolific and adaptable species, the Eastern Gray Squirrel has been introduced to, and thrives, in several regions of the western United States.