38 Sciurus abertithe body and the tail is white; and the tail is black on the
dorsal side, overlaid with white hairs.
S. a. ferreus—extreme southcentral Wyoming and Colorado,
and northern New Mexico east of the Río Grande (USA).
This subspecies is small, with a relatively short tail and
variable coloration, including an all black phase, a dark
brown phase, and a normal phase. The normal phase
consists of a steel gray back, usually a mid-dorsal reddish
patch, and a black lateral band. The body and tail are
white ventrally, and the tail black dorsally, with scat-
tered white hairs.
S. a. kaibabensis—Kaibab Plateau, north of the Grand Can-
yon (USA). It is of medium size, with relatively the short-
est tail of any of the S. aberti subspecies. It is steel gray
dorsally, usually with a reddish dorsal patch. The venter
is black or blackish gray; and the tail white dorsally and
ventrally, with a few black dorsal hairs.
conservation: IUCN status—least concern. Population
trend—stable.
habitat: Abert’s squirrels are often suggested to be obli-
gates of ponderosa pine (Pinus ponderosa) forests that contain
abundant conifer seeds and moderately closed canopies for
effi cient foraging and protection from predators. Areas used
by Abert’s squirrels typically have denser growth than other
por t ions of t he forest. Recent ev idence sug gest s t hat S. aberti
uses and can persist in more diverse coniferous forests. Mo-
saic, heterogeneous, and unevenly aged forests are particu-
larly favored.natural history: This species is diurnal. S. aberti dem-
onstrates a strongly seasonal reproductive pattern, with
males possessing scrotal testes in winter through summer,
after which the testes are withdrawn into the abdominal
cavity. Females are in estrus for less than one day, when
males are attracted to and compete for access to them
through a linear dominance hierarchy. Females mate with
multiple males and solicit copulations from some low-
ranking males. Females produce a single litter (averaging
3.2–3.4 young) each year, typically in late spring or early
summer, after a gestation of 46 days. However, a female
may produce a second litter in some localities. Paternal
care is not provided, and the young remain with their
mother until natal dispersal, at about 10 weeks of age. Most
individuals are able to reproduce by the time they are 1Sciurus aberti. Photo courtesy Randall D. Babb. Sciurus aberti kaibabensis. Photo courtesy Randall D. Babb.