The San Joaquin antelope squirrel or Nelson's antelope squirrel (Ammospermophilus nelsoni), is a species of antelope squirrel, in the San Joaquin Valley of the U.S. state of California.
Distribution and habitat
The San Joaquin antelope squirrel is found in the San Joaquin Valley, including slopes and ridge tops along the western edge of the valley. The binomial of this species commemorates the American naturalist Edward William Nelson.
Description
Physical Characteristics
The San Joaquin antelope squirrel is dull yellowish-brown or buffy-clay in color on upper body and outer surfaces of the legs with a white belly and a white streak down each side of its body in the fashion of other antelope squirrels.
Breeding
Studies by Hawbecker provide abundant information on breeding and the life cycle of Nelson's antelope squirrel. Once pregnant, gestation lasts a little less than a month. There is usually about 1 per hectare. Nelson's antelope squirrel prefers deep, rich soil types since they are easy to dig through in both winter and summer temperatures. Although these squirrels may dig for food, they do not make their own burrows. Instead they claim abandoned Dipodomys (kangaroo rats) burrows as their own.
Nelson's antelope squirrels are cautious when emerging from their burrows.
Threats
Increasing agriculture and urban development is an increasing problem for Nelson's antelope squirrel. This species will not colonize cultivated land. Therefore, an increase in agriculture land is taking away their habitat and leaving them with no alternative. Grazing livestock further destroys what habitat may be left, and exotic plants are able to take over native grasses that the squirrel forages upon and relies on for shade and cover. Prescribed burns are one option to control invasive plant species, however this method can cause native species to also be killed and can be expensive.