about 20 rods wide and approximately 4 miles long, an area of
approximately 160 acres, particular note being taken of the kind of
shrub under which each mound was located. Of 300 mounds in this area, 96
were under _Prosopis_, 95 under _Acacia_, 65 under _Celtis_, 11 under
_Lycium_, 31 in the open, 1 about a "cholla" cactus (_Opuntia
spinosior_), and 1 about a prickly pear (_Opuntia_ sp.). There is
apparently no strongly marked preference for any single species of
plant. While both desert hackberry and the cat's-claws afford a
better protection than mesquite--since cattle more often seek shade
under the latter, and in so doing frequently trample the mounds
severely--it appears that the general protection of a tree or shrub of
some sort is sought by kangaroo rats, rather than the specific
protection of the thickest or thorniest species.

The following records indicate particular habitat preferences of
_spectabilis_ as noted at different points in its range:

Occurs on open bare knolls exposed to winds, also on gravelly
places at lower edge of foothills (Franklin Mountains, Tex., Gaut);
here and there over the barest and hardest of the gravelly mesas
(Bailey, Tex., 1905, 147); on open creosote-bush and giant-cactus
desert (Tucson, Ariz., Vorhies and Taylor); on firm, gravelly, or
even rocky soil on the grassy bajada land along the northwest base
of the mountains, either in the open or under _Celtis_, _Prosopis_,
_Lycium_, _Acacia greggii_, or other brush (Santa Rita Mountains,
Ariz., Vorhies and Taylor); mounds usually thrown up around a bunch
of cactus or mesquite brush (Magdalena, Sonora, Bailey); in heavy
soil (Ajo, Ariz., A. B. Howell); loamy soil (Gunsight, Ariz., A. B.
Howell); in mesa where not too stony (Magdalena, Sonora, Bailey);
grassy plain (Gallego, Chihuahua, Nelson); in open valley and high