brevifolia (Martinez-Berdeja and Ezcurra 2015) suggesting that other species may benefit from the fruit-carrying behavior of Ammospermophilus
The Baja California Peninsula (Figure 3) showed three sub-areas: a) Baja California Peninsula, including the states of Baja California and Baja California Sur, based on Ammospermophilus
leucurus, Chaetodipus arenarius (CI=0.33), Dipodomys simulans, Neotoma lepida and Sylvilagus bachmani; b) Northern Baja California Peninsula, including the state of Baja California, based on Chaetodipus californicus, C.
This life-form is represented in Asia by susliks (Spermophilus and Spermophilopsis, both members of the squirrel family Sciuridae); in North America by ground squirrels (Spermophilus and Ammospermophilus
, both Sciuridae); and in South America by guinea-pigs and similar genera (Cavia, Galea, and Microcavia, all of the guinea-pig family Caviidae).
Sciurid species (which included Spermophilus beecheyi, Ammospermophilus
leucurus, and Xerospermophilus tereticaudus) were grouped as "ground squirrels" and analyzed separately from other rodent species (Neotoma lepida and species of Dipodomys, Peromyscus, Chaetodipus, and Perognathus).
leucurus) were captured in a total of >6000 trap-nights (TN), but only two species were recorded on islands.
leucurus while excluding Marmota spp.
The most numerous mammals are the rodents, especially the kangaroo rats (Dipodomys), the pocket mice (Chaetodipus), and the antelope ground squirrels (Ammospermophilus
), named because the tail is often carried up or over the back, like the American pronghorn antelope (Antilocapra americana).
We caught reasonable numbers of the only diurnal species present at our sites (Ammospermophilus
leucurus), and used these data as well as those for nocturnal species in our analyses.
In a Sonoran Desert community of four granivorous species (Arizona pocket mouse, Perognathus amplus; Merriam's kangaroo rat, Dipodomys merriami; round-tailed ground squirrel, Spermophilus tereticaudus; and Harris's antelope squirrel, Ammospermophilus
harrisii), we concluded that two mechanisms were jointly responsible for community organization.
We used number of fecal deposits (scats) as an estimate of relative abundance of coyotes and lagomorphs (Lepus and Sylvilagus) and presence of small burrows as an estimate of relative abundance of small mammals (Ammospermophilus
Records for Ammospermophilus
interpres, Geomys texensis and Vulpes vulpes represent range extensions.
The maintenance nitrogen requirement of adult antelope ground squirrels (Ammospermophilus
leucurus) varied seasonally from 481 mg [kg.sup.-0.75] day 1 in the autumn to 505 mg [k.sup.-0.75] [day.sup.-1] during spring (Karasov, 1982).
Texas antelope squirrels (Ammospermophilus
interpres) are distributed widely across xeric environments of western Texas, but rarely are abundant (Schmidly, 2004).
Noteworthy records include an unusually high population of Ammospermophilus
interpres, and an apparently isolated group of Chaetodipus nelsoni, which provides the northernmost record for the species in the Trans-Pecos, and evidence of the continuing northern expansion in western Texas of the javelina (Tayassu tajacu).