They are opportunistic and omnivorous feeders, consuming a wide variety of plant and animal food from fruits and seeds to worms, insects and small vertebrates.

[5] "Tinamidae" was defined as by Gauthier and de Queiroz (2001): "Tinamidae refers to the crown clade stemming from the most recent common ancestor of Tetrao [Tinamus] major Gmelin 1789 and all extant birds sharing a more recent ancestor with that species than with Struthio camelus Linnaeus 1758 and Vultur gryphus Linnaeus 1758.

The ecological niche for large, flightless herbivores was thus already occupied, forcing tinamous to retain smaller-bodied, omnivorous, and volant lifestyles.

[12] Flight-capable lithornithids from the Paleocene and Eocene epochs appear to have been structurally the most similar precursors to the tinamous, and may have been ancestral to them as well as to the ratites, though their precise relationships are unclear.

[3][14] The earliest unequivocally Tinamiforme fossil material dates from the Miocene,[15] but flightless ratite-like taxa from the Paleocene may belong to this group.

[17] Associated fossils indicate that the local palaeoenvironment at the beginning of this period was characterised by a humid, subtropical climate, with forest vegetation, becoming drier and more open with time.

Some of the tinamou fossil material appears to be intermediate between the two subfamilies, suggesting that the period coincides with the origins of the radiation of the Nothurinae into the expanding open-country habitats.

[15][18] Nothurine fossils referrable to Eudromia and Nothura have been found in the Late Miocene Cerro Azul Formation from the Pampean region of central-southern Argentina.

[8] The plumage of the family is cryptic, as is usual with ground birds, with typical colors ranging through dark brown, rufous, buff, yellow and grey.

Their tails are short, sometimes hidden behind the coverts, and possibly indicative of an ability to sacrifice feathers to a predator in order to escape when grasped.

[8] Rheas are only found in open country, curassows and guans are generally limited to forests, and the pheasant family is only represented by a few species in the north of the region.

Tinamous inhabit most parts of South and Central America, as well as the tropical regions of Mexico, with the exception of aquatic, snow-covered, and true desert habitats, and the southernmost tip of Patagonia.

Behavioral and ecological separation of tinamou species is evident where their ranges overlap through the utilization of different food sources and occupation of limited micro-habitats.

Size difference allows the red-winged tinamou and the spotted nothura to coexist, as they both occupy the same habitat of Brazil, the tropical savanna.

The ornate tinamou lives mainly upslope in hilly puna grassland but will move each morning to the bottom of the slopes to feed and drink.

They take off with rapid and noisy wing beats, until they have gained sufficient altitude, then glide while slipping sideways, with an occasional further burst of flapping.

In order to minimize the effort involved in ascending to their roosts, in hilly terrain they will access them from uphill and, when threatened, will fly downhill to gain more distance from the threat.

In Tinamus species, the male will lower his chest to the ground, stretch his neck forward, and fluff up his back to appear larger than normal.

[27] Tinamous always nest on the ground; in open areas, near a bush; in scrub, in a dense patch of grass; in forest, at the base of a tree trunk between the buttresses.

Nothura, Nothoprocta and Eudromia, comprising open country birds, eat mainly seeds and other soft vegetative matter.

Much of the animal food consists of insects, including ants, termites, beetles, grasshoppers, Hemiptera, and lepidopteran larvae, as well as gastropods, mollusks, worms, and small vertebrates, such as amphibians and reptiles.

Forest tribes of Brazil and Colombia believe the jaguar imitates the call of the great tinamou in order to track and eat it.

The red-winged tinamou has been reintroduced to the state of Rio de Janeiro, Brazil, where its wild population was hunted to extermination at the turn of the 20th century.

[29] It was not until 2003 that the first scientific symposium on tinamous was organized at the VIIth Neotropical Ornithological Congress, held at Termas de Puyehue, Chile.

[26] The status of the family is not easy to determine as many species live in the Amazon Basin or the far reaches of the Andes and attract little attention, even from ornithologists.

[30] The solitary tinamou is listed under Appendix I of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora).

The tepui tinamou's range is limited to the tops of a handful of plateaus in the cloud forests of Venezuela, making it highly vulnerable to any threat.

In the late 19th and early 20th century hunting was responsible for mass killing within the family, with the elegant crested tinamou and spotted nothura popular targets.

Frank Chapman of the American Museum of Natural History helped raise awareness about the rate of exploitation and its potential impact on the populations of the species.

Overall, there is a lack of adequate controls in place to ensure sustainable hunting, as well as insufficient resources and determination to enforce existing regulations.