The tail is usually narrower and shorter than the head and body. There are usually five dark stripes, alternating with light stripes, on the back and sides, somewhat like the pattern of the chipmunk Eutamias. The general dorsal background color is yellowish brown, and the underparts are white, pale brown, or bright red. The ears are usually tufted with white, and the tail is slender and rather thinly furred. Apparently, there are two molts per year, since the winter and summer coats are somewhat different in color.
Females have six mammae.
These squirrels live in various kinds of forest, including jungle, coniferous growth, and low scrub, from sea level to about 1,525 meters. They are arboreal and live in holes in trees. They are active during the day, especially in the early morning. The diet includes fruits, nuts, seeds, and a substantial portion of insects. T. macclellandi may damage ripening corn crops in some areas.