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. Fox squirrel species live throughout most of the United States, excluding the eastern coast. It is the largest type of squirrel ranging from 17 to 27 inches long. These large squirrels come in two distinct color groups.One has dark fur in variable shades from black to gray and tan or gold undersides.wo species of gray squirrels inhabit the United States, the western gray and the eastern gray. The eastern gray squirrel normally inhabits the northeastern United States, although it has invaded the western United States, as well as Europe.