The soles of the feet are smooth. The intestinal tract is approximately 790 mm in length, not including the stomach or cecum. The facial part of the skull is inflated by pneumatic cavities. The four cheek teeth are flat and have a wavy enamel pattern. They are incompletely rooted and moderately to strongly high-crowned.
Females have two or three pairs of mammae, which are located on the sides of the body.
Old World porcupines inhabit deserts, savannahs, and forests. They shelter in caves, crevices, holes dug by other animals, or burrows they have excavated themselves and construct a nest of plant material within the den. They are mainly nocturnal and terrestrial, walking ponderously on the sole of the foot with the heel touching the ground. They run with a shuffling gait or gallop clumsily when pursued. Except for Trichys, they rattle their spines when moving about and may also stamp their feet when alarmed.