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.
American red squirrels can live for up to 9 years. 2 For juveniles less than 1 year of age, females tend to survive longer than males.3 The opposite is true for adult red squirrels. Another predictor of longevity for red squirrels is whether or not theyâre born at a time in which seeds are abundant.