Squirrels of the World

Notocitellus annulatus 291

natural history: These squirrels typically dig burrows
that are branched and up to 60 cm deep. The tropical ground
squirrel is technically omnivorous, but it is strongly gra-
nivorous whenever seeds are available. These animals
have been reported to feed on the seeds and fruits of Aca-
cia, Prosopis, Crescentia, and Prunus. This species’ reliance
on agricultural crops—corn (maize), sorghum, and beans—
may contribute to occasional range expansions. The tropi-
cal ground squirrel is diurnal, social, and generally active
year-round, although estivation may occur in the warmest
months of the year, when food is less abundant. These
squirrels frequently vocalize, giving high-pitched “chirps”
in the presence of humans and potential predators. Only
one louse (Neohaematopinus traubi) is reported from N.
adocetus, but ectoparasites are likely to be common. Al-
though not listed as threatened in México, it is one of 122
vertebrate and vascular plant species, and one of 11 mam-
mal species, considered key species for conservation
within the Transvolcanic Belt of central México.

general references: Best 1995g; de Grammont and Cua-
rón 2008; Hayssen 2008a; Herron, Castoe, et al. 2004; Sánchez-
Cordero et al. 2005; Velázquez et al. 2003.

Notocitellus annulatus Audubon and

Bachman, 1842

Ring-Tailed Ground Squirrel

description: This squirrel is similar to N. adocetus, but N.
annulatus is larger, with a longer narrower rostrum. The tail
of N. annulatus has obvious pale-colored rings; its pelage is
darker and more reddish than that of N. adocetus.

size: Female—HB 219.3 mm; T 207.6 mm; Mass 386.3 g.
Male—HB 221.2 mm; T 215.2 mm; Mass 260.0 g.
Sex not stated—HB 209.5 mm; T 208.0 mm.

distribution: The ring-tailed ground squirrel occupies a
narrow range along the Pacifi c coast of western México,
from Nayarit through Jalisco, Colima, Michoacán, and
northern Guerrero.

geographic variation: Two subspecies are recognized.

N. a. annulatus—northern third of the species’ range, from
Nayarit to Jalisco (México). See description above.
N. a. goldmani—southern two-thirds of the species’ range,
from Jalisco to Guerrero (México). The reddish tinge

on the face, neck, thighs, and tail is less extensive and

intense.

conservation: IUCN status—least concern. Population

trend—no information.

habitat: The ring-tailed ground squirrel is found at eleva-

tions from sea level to 1200 m. It typically occurs in dry

tropical deciduous forests, sometimes in association with

fi gs (Ficus), but also oil palm (Elaeis), mesquite (Prosopis), or

catclaw (Acacia). Although ground burrows in sand or rocky

cliff s and outcrops are common, N. annulatus is also re-

ported to nest in tree cavities.

natural history: This species is primarily granivorous,

eating a variety of seeds, fruits, and nuts from the plants

Notocitellus annulatus. Photo courtesy Troy L. Best.