Approximately 10,000 years ago the Kaibab Squirrel (Sciurus kaibabesis) was geographically separated from a common ancestor of the Abert’s squirrel. This separation cut off the gene flow from the Abert’s squirrel and the Kaibab squirrel began to evolve on its own. While the two are still closely related the Kaibab squirrel developed noticeable differences such as a dark belly and forelimbs. Their tails are white and the backs of their heads, a chestnut brown.
In 1972, seven female Kaibab squirrels and one male were transplanted to Mt. Trumbull on the present day Parashant National Monument. Because the squirrel populations were localized on the Kaibab Plateau, scientists feared that a plague could wipe out the entire species. For five years, they released additional squirrels to the back-up community on Mt. Trumbull to mix the gene pool and make a self-sustaining population.
Last updated: December 3, 2019