On average, the Indian porcupine's head and body measure 70-90 centimetres (cm) in length, with the tail adding an additional 8-10 cm. Its hair is highly modified to form multiple layers of spines. Beneath the longer, thinner spines lies a layer of shorter and thicker ones. Each quill is brown or black in colour, with alternating bands of white. Spines vary in length, with the neck and shoulder quills being the longest, measuring 15 to 30 cm. The tail is covered with with shorter spines that appear white in colour. Among these are longer, hollow, rattling quills that are used to alarm potential predators. The feet and hands are broad, with long claws that are used for burrowing.