Species of squirrels include the red-bellied squirrel, the miscellaneous squirrel, the Purple long-nosed squirrel, the Yucatan squirrel, the rock squirrel, the giant squirrel, the goldenrod squirrel, the snow squirrel, the shrimp squirrel, the prairie dog squirrel, the Japanese little flying squirrel, the North American red squirrel, the European red squirrel, the North American gray squirrel, the tricolor squirrel, the red-cheeked long-nosed squirrel, the red-cheeked long-nosed squirrel, the orange-throated long-nosed squirrel, and so on.

The red-bellied squirrel inhabits tropical and subtropical forests, and is also found in secondary forests, logging sites, and vegetation environments such as hilly terraces, coconut groves, shrub forests, bamboo forests, mixed forests of trees and bamboos, Sargasso pine forests, fir forests, and thickets, etc. It is an arboreal animal.

Percher's long-snouted squirrel has a slender body, tail length is less than the body length, tail hair is fluffy, the forelimbs are 4-fingered, the hind limbs are 5-toed, the back hair color is olive-yellowish-gray from the head to the base of the tail, the side of the body, the outer limbs, and the mandibles and the base of the abdominal hairs are light gray, and the rest is white.

Per's long-nosed squirrels are mainly arboreal, mostly in valleys, rivers and streams next to the trees, morning and evening activities, sometimes running from the trees to the ground activities, walking through the bushes, but also active in the forest on the fallen trees, and the side of the activities while looking for food.