Tinamous form an order (Tinamiformes), comprising a single family (Tinamidae) with two distinct subfamilies, containing 47 species of birds found in Mexico, Central America, and South America. The word "tinamou" comes from the Galibi term for these birds, tinamu. One of the most ancient living groups of bird, they first appear in the fossil record in the Miocene epoch. Tinamous have traditionally been regarded as the sister group of the flightless ratites, but recent work places them well within the ratite radiation, implying basal ratites could fly. They are generally sedentary, ground-dwelling and, though not flightless, when possible avoid flight in favour of hiding or running away from danger. They are found in a variety of habitats, ranging from semi-arid alpine grasslands to tropical rainforests. The two subfamilies are broadly divided by habitat, with the Nothurinae referred to as steppe or open country tinamous, and the Tinaminae known as forest tinamous.