The species vary considerably in colour, being brown, reddish, dull orange, greyish or blackish, but typically with lighter underparts. Their bodies are covered with coarse hair which is raised when alarmed. They weigh 2.4–6 kg (5.3–13.2 lb) and are 44.5–76 cm (17.5–29.9 in) in length, with short, hairless tails.[