Adults weigh 125-7,000 grams. The fur is long, soft, and fine in pikas and usually thick and soft in rabbits and hares, but it is coarse in some forms. Males do not have a baculum. Females have two to five pairs of mammae. In adults the smaller second upper incisor is located directly behind the first incisor and lacks a cutting edge.
Rodents have only a single upper pair of incisors.
The incisors grow throughout life and are completely covered by enamel. The roots of the upper incisors are located in the premaxillary bones of the skull, whereas the lower incisors are of variable length. The cheek teeth are high-crowned and lack roots. In lagomorphs the upper toothrows are farther apart than the lower toothrows. The jaw movements of pikas, rabbits, and hares are vertical or transverse.