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.
The gray mouse lemur has a reproductive lifespan of five years, although captive individuals have been reported to live up to 15 years. Although threatened by deforestation, habitat degradation, and live capture for the pet trade, it is considered one of Madagascar's most abundant small native mammals.he gray mouse lemur tends to prefer lower levels of the forest and the understory, where branches and vegetation are dense. In secondary forest, it is generally observed from ground level up to 10 m (33 ft) above ground, yet 15 to 30 m (50 to 100 ft) in the canopy of primary forest.