It is named in honor of the American naturalist John James Abert; nine subspecies are recognised.

It is recognizable by its tufted ears, gray color, pale underparts and rufous patch on the lower back.

The squirrel feeds on the seeds and cones of the Mexican pinyon and the ponderosa pine when they are available, but will also take fungi, buds, bark, and carrion.

This gives this species a striking similarity to the Eurasian red squirrel, aside from its differing dark coloration.

[7] Abert's squirrels transplanted to the Graham and Santa Catalina Mountains of Arizona have established stable populations.

[9] The distribution of Abert's squirrel subspecies in the Southwest is coincident with the disjunct ponderosa pine forests.

[10] Subspecies distributions are as follows:[5][11] Abert's squirrels in the U.S. make almost exclusive use of ponderosa pine for cover, nesting, and food.

[5] In Mexico where ponderosa pines are absent, the species is found in stands of the closely related Pinus arizonica.

[5] Ramey reports that the mean Abert's squirrel home range for spring and summer was 20 acres (8.1 hectares) in Black Forest, Colorado.

[20] Abert's squirrel is closely associated with, and nearly confined to cool, dry interior ponderosa pine forests.

[5] Findley and others mention that Abert's squirrels are common in mixed conifer canyons in New Mexico.

[22] In Durango and Chihuahua the squirrels are said to inhabit high altitude ponderosa pine stands.

[12] However, the ponderosa pines of Mexico have relatively recently (since at least 1997) been reclassified as a separate species Pinus arizonica (syn.

[5] Hall and Kelson, however, report that two litters are often borne per year in the southern parts of Abert's squirrel range.

[5] Summer nests are built by Abert's squirrels on ponderosa pine branches, in Gambel oak cavities, and sometimes in cottonwood (Populus spp.)

[27] Nests are placed from 16 to 90 feet (4.9–27) above the ground, usually on a large limb against the bole, or in the forks of smaller branches.

[10][15] Dwarf mistletoe (Arceuthobium vaginatum) infestations that cause the formation of "witches brooms" are often incorporated into or support Abert's squirrel nests.

[28] Nests are roughly spherical and a small platform often extends beyond the bowl edge on one side.

[5] In winter, pairs of Abert's squirrels, usually an adult female and one subadult (presumed) offspring, use the same nest for shelter.

[21] After seeds have been disseminated Abert's squirrels are dependent on inner bark, which forms the bulk of the diet from November to April.

[5] Fleshy fungi consumed include members of the following genera: Agaricus, Amanita, Boletus, Hypholoma, Lepiota, Lycopedon, Russula and Tuber.

Mushrooms poisonous to humans are consumed by Abert's squirrels without difficulty, including destroying angels (A. bisporigera and A. ocreata) and a species of Russula.

Hawks (Accipitridae and Falconidae) prey on Abert's squirrels in central Arizona, but even though other potential predators are present, i.e., gray fox (Urocyon cinereoargenteus), bobcat (Lynx rufus), coyote (Canis latrans), there is no evidence that they prey on Abert's squirrels.