Class Mammalia Linnaeus, 1758 - mammals
Order Rodentia Bowdich, 1821 - rodents
Suborder Sciurognathi (Tullberg, 1899)
see Suborder Sciuromorpha Brandt, 1855
Family Sciuridae Batsch, 1788 - squirrels, chipmunks, marmots, and prairie dogs
Subfamily Sciurinae Batsch, 1788 - tree and ground squirrels
Genus Spermophilus Cuvier, 1825 - ground squirrels
01 Spermophilus adocetus Merriam, 1903 - tropical ground squirrel
02 Spermophilus alashanicus Büchner, 1888
03 Spermophilus annulatus Audubon & Bachman, 1842 - ring-tailed ground squirrel
04 Spermophilus armatus Kennicott, 1863 - Uinta ground squirrel
05 Spermophilus atricapillus W. Bryant, 1889 - Baja California rock squirrel
06 Spermophilus beecheyi (Richardson, 1829) - California ground squirrel
07 Spermophilus beldingi Merriam, 1888 - Belding's ground squirrel
08 Spermophilus brunneus (A.H. Howell, 1928) - Idaho ground squirrel
09 Spermophilus canus Merriam, 1898 - gray ground squirrel
10 Spermophilus citellus Linnaeus, 1766 - European souslik
11 Spermophilus columbianus (Ord, 1815) - Columbian ground squirrel
12 Spermophilus dauricus Brandt, 1843 - Daurian ground squirrel
13 Spermophilus elegans Kennicott, 1863 - Wyoming ground squirrel
14 Spermophilus erythrogenys Brandt, 1841
15 Spermophilus franklinii (Sabine, 1822) - Franklin's ground squirrel
16 Spermophilus fulvus Lichtenstein, 1823 - large-toothed souslik
17 Spermophilus lateralis (Say, 1823) - golden-mantled ground squirrel
18 Spermophilus madrensis Merriam, 1901 - Sierra Madre ground squirrel
19 Spermophilus major Pallas, 1778 - russet souslik
20 Spermophilus mexicanus (Erxleben, 1777) - Mexican ground squirrel
21 Spermophilus mohavensis Merriam, 1889 - Mohave ground squirrel
22 Spermophilus mollis Kennicott, 1863 - Piute ground squirrel
23 Spermophilus musicus Ménétries, 1832
24 Spermophilus parryii (Richardson, 1825) - Arctic souslik
25 Spermophilus perotensis Merriam, 1893 - Perote ground squirrel
26 Spermophilus pygmaeus Pallas, 1778 - little souslik
27 Spermophilus relictus Kashkarov, 1923 - Tien Shan souslik
28 Spermophilus richardsonii (Sabine, 1822) - Richardson's ground squirrel
29 Spermophilus saturatus (Rhoads, 1895) - Cascade golden-mantled ground squirrel
30 Spermophilus spilosoma Bennett, 1833 - spotted ground squirrel
31 Spermophilus suslicus Güldenstaedt, 1770 - spotted souslik
32 Spermophilus tereticaudus Baird, 1858 - round-tailed ground squirrel
33 Spermophilus townsendii Bachman, 1839 - Townsend's ground squirrel
34 Spermophilus tridecemlineatus (Mitchill, 1821) - thirteen-lined ground squirrel
35 Spermophilus undulatus Pallas, 1778 - long-tailed souslik
36 Spermophilus variegatus (Erxleben, 1777) - rock squirrel
37 Spermophilus washingtoni (A.H. Howell, 1938) - Washington ground squirrel
38 Spermophilus xanthoprymnus Bennett, 1835
39 Subgenus Otospermophilus Brandt, 1844
40 Subgenus Spermophilus F. Cuvier, 1825
44 Subgenus Poliocitellus Howell, 1938
45 Subgenus Callospermophilus Merriam, 1897
46 Subgenus Ictidomys J. Allen, 1877
47 Subgenus Xerospermophilus Merriam, 1892