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.
Squirrel Facts & Squirrel Information. Two species of squirrel found on the West Coast are the native Douglas Squirrel (or Red Squirrel family) and the Eastern Grey Squirrel. The grey squirrel is the most common of the two species found locally in the Lower Mainland. The grey squirrel is originally from eastern North America and was introduced into Stanley Park in 1912. The grey squirrel population remained relatively contained until the late 1980's.