Great Basin Pocket Mouse
This pocket mouse can be found in the Great Basin from South British Columbia (Canada), south to eastern California and east to southeast Wyoming and northwest Arizona. The Great Basin pocket mouse can be found in shrub/grassland communities of sagebrush, shadscale, greasewood, mountain mahogany, and bitterbrush. Habitats dominated with shrub are useful in vegetative cover, while also providing better and more diverse food resources.
Great Basin pocket mouse
The upper parts of its body are a pinkish buff color, which is thinly to heavily overlaid with a blackish color, while the underparts vary from white to buffy. The soft coat of this mouse has no bristles. One molt takes place in late summer. The soles of its hind feet are hairy, and the tail is long and bicolored. Its hind limbs are about the same length of its forelimbs, and the Great Basin pocket mouse moves about on all four legs. While the hind legs provide support, the forefeet dig with claws through sand to find seeds. These seeds are then placed in fur-lined external cheek pouches, which open alongside its mouth.
Reproduction
From about late April to early August, males are in breeding condition, while females show the first sign of estrus in April. Early June is probably when breeding occurs at its peak. Pregnancies then occur from May to July. Gestation lasts 21 to 25 days. When there is an abundance of food, females have an average of two litters per year. Some have even been found to have three litters. Otherwise, an average of 1.1 litters is produced. Litters vary from three to eight mice. Juveniles born early in the season are able to breed themselves by late summer.
Behavior
Most individuals remain underground from December to March, but for the rest of the year they emerge for an average of sixty days to ninety days, depending on the abundance of food. They return to their burrows from late summer to early fall. Great Basin pocket mice are nocturnal and stay in their burrows during the day. The entrances of the burrows, usually hidden under shrubs, are covered with earth in order to maintain a low temperature and high humidity. It has been found that the peak population in south-central Washington during autumn was an average of 320 individuals in a 2.7 ha. study area. The home range was 1,560-4,005 square meters for males and 508-2,301 square meters for females.
Food Habits
Its diet consists mostly of seeds of forbs, grasses and shrubs. Along with green vegetation, insects are eaten particularly when they are abundant. In captivity they should be offered a complete diet of rodent lab blocks, and rat or mouse mix, with bits of fruit or veggies regularly. Cheerios or wheat bread are great treats, in small quantities. Do NOT feed chocolate, fried foods, salted foods, candy or junk food! They may enjoy crickets and mealworms if they are captive bred, never feed wild insects as they may carry parasites.
Vitamins, like Nutri-Cal are a good addition to their diet, and added calcium during nursing and growth due to demands on their systems at those times, but take care not to overdo it. Water bottles should be used to proved constant, clean water. Ceramic or stoneware food dishes work well for keeping seeds or fresh foods off the floor, and a wire mesh hopper that allows them to eat the lab blocks through without extra waste.
