Breeding peaks by April. Females produce one litter per year of 5-6 young. By mid-June, young chipmunks are seen outside the burrow. In two months, they are nearly full grown and independent. Favorite foods of the least chipmunk include wild berries and seeds from coniferous trees.
Cactus fruit is eaten when available.
Insects are also frequently preyed upon, especially beetles, grasshoppers, and caterpillars. Least chipmunks fall prey to red-tailed and other hawks, weasels, mink, and feral domestic cats.