The Mt. Graham red squirrel (Tamiasciurus fremonti grahamensis) is a subspecies that is only found on Mt. Graham in southeastern Arizona. It was actually thought to be extinct in the 1950s until they were rediscovered two decades later. On June 3, 1987, the Mt. Graham red squirrel was listed as endangered under the Endangered Species Act.

Recent analyses indicate that the Mt. Graham red squirrel belongs to a different species than the North American red squirrel that ranges across much of the United States and Canada. Instead, the Mt. Graham red squirrel appears to be a subspecies of Fremont’s squirrel – a species found in Arizona, New Mexico, Colorado and Utah. It is distinguished by a smaller body and narrower head, but maintains the brownish-red sides and white belly that characterize other squirrels in its species.

Mt. Graham red squirrels are most active during the day and spend their time foraging for seeds of coniferous trees; however their diet also consists of insects, mushrooms, bird eggs, nestlings and various other items. Both genders are highly territorial and will aggressively defend their midden (territory) from other squirrels. Like other members of its species, Mt. Graham red squirrels do not hibernate during the winter, but will only venture out during mid-day when it’s warmest.

The forest habitat of the Mt Graham red squirrel has been impacted by wildfire and disease, reducing the available food resources and cover from predators. This has led to a reduction in their wild population. In addition, an introduced squirrel species (Abert’s squirrel) is now outcompeting Mt. Graham red squirrels for limited food resources.

At the Phoenix Zoo

The Arthur L. and Elaine V. Johnson Foundation Conservation Center at the Phoenix Zoo currently maintains a population of Mt. Graham red squirrels, which are housed in a temperature regulated building. Because the temperatures in Phoenix are much higher than on Mt. Graham, the building is maintained at 65 – 72F degrees throughout the year.

To help natural populations, the Zoo is working with the U.S. Fish and Wildlife Service to develop a pilot breeding program, focusing on establishing a sustainable method to breed and release Mt. Graham red squirrels back into the wild. Over the next several years we will be working to develop breeding management protocols and general husbandry guidelines designed to produce animals that can survive reintroduction. We are hopeful that through the conservation efforts of the Zoo and other organizations, the Mt. Graham red squirrel will be present in its natural habitat for years to come.

Learn More about Mt. Graham Red Squirrel Research