Squirrels of the World

Ammospermophilus insularis 251

274 m (on average) and thus have modest home ranges. Har-
ris’s antelope squirrels are extremely energetic and rarely re-
main motionless, except when sitting on their haunches atop
a tall boulder or cactus. Their alarm vocalization is a long
pure-noted trill. These squirrels hold their tails straight up-
ward when scurrying about the ground, stopping to forage
for seeds on the desert fl oor. Due to their small body size
and diurnal habits, A. harrisii is a likely prey of foxes, coyotes
(Canis latrans), procyonids, small felids, raptors, and snakes. In
urban areas Harris’s antelope squirrels occasionally become
pests in gardens, but never at more than a localized scale.

general references: Best, Titus, Caesar, et al. 1990; Bolles
1988.

Ammospermophilus insularis (Nelson and

Goldman, 1909)

Espiritu Santo Island Antelope Squirrel

description: A. insularis is gray to slate gray on t he dorsum
and head, with a white stripe running along each side. The
venter is white to cream. The snout and legs are suff used
with light orange to rust. The tail is grizzled gray with a
whitish underside and a band of black near the tip of the tail.

size: Both sexes—TL 229 mm (210–240 mm); T 78 mm (71–
83 mm).

distribution: This squirrel is endemic to Espiritu Santo
Island, Baja California Sur (México).

geographic variation: None. A. insularis was proposed

as a subspecies of A. leucurus by Álvarez-Castañeda, and Hel-

gen et al. followed this classifi cation.

conservation: IUCN status—not listed. Population

trend—no information. A. insularis is considered threatened

in México.

habitat: Espiritu Santo Island is characterized by rocky

volcanic slopes with sparse vegetation, in which this spe-

cies is found.

natural history: A. insularis is diurnal, but little else is

known about this small island endemic. This squirrel’s call

Ammospermophilus harrisii. Photo courtesy Randall D. Babb.

Ammospermophilus insularis. Photo courtesy Troy L. Best.