Small, dark-colored eye patches are present, and the muzzle, lips, cheeks, and edges of the ears are white. The back of the ears, the limbs, and the underparts are dark reddish brown to black. The head is rather round, the ears are large and pointed, the feet have hairy soles, and the claws are semiretractile. The nonprehensile tail is about two-thirds as long as the head and body. There are glandular sacs in the anal region.
Females have four mammae.
The lesser panda inhabits mountain forests and bamboo thickets at elevations of 1,800-4,000 meters. It is nocturnal and crepuscular, sleeping by day in a tree. Although Ailurus is a capable climber, it seems to do most feeding on the ground. The diet consists mostly of bamboo sprouts, grasses, roots, fruits, and acorns. It also occasionally takes insects, eggs, young birds, and small rodents.