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.
Fox squirrels can live for about 13 years both in captivity and under natural conditions. 8 One of the primary factors in how long a fox squirrel will survive is the availability of food, especially for younger squirrels. 7. As with eastern gray squirrels, female fox squirrels seem to live longer than their male counterparts. The oldest recorded age for a female fox squirrel is just under 13 years, whereas that of a male fox squirrel is a little over 8 years. 8. Southern Flying Squirrel. Southern flying squirrels have gray backs and white bellies.