Phylogenetically, they branched off from the core Galliformes after the Cracidae (chachalacas, guans, and curassows) and before the Odontophoridae (New World quail).

An Eocene fossil lineage Telecrex has been associated with guineafowl; Telecrex inhabited Mongolia, and may have given rise to the oldest of the true phasianids, such as blood pheasants and eared pheasants, which evolved into high-altitude, montane-adapted species with the rise of the Tibetan Plateau.

[2] Numida Agelastes Guttera Acryllium The insect- and seed-eating, ground-nesting birds of this family resemble partridges, but with featherless heads, though both members of the genus Guttera have a distinctive black crest, and the vulturine guineafowl has a downy brown patch on the nape.

Guineafowl travel behind herd animals and beneath monkey troops, where they forage within manure and on items that have fallen to the understory from the canopy.

Their breast muscles are dark (aerobic metabolism), enabling them to sustain themselves in flight for considerable distances if hard-pressed.

Some species of guineafowl, like the vulturine, may go without drinking water for extended periods, instead sourcing their moisture from their food.

Once hatched and ready to leave the brooder (around three weeks), they may be enclosed in a coop for at least three days so they learn where "home" is.

The helmeted guineafowl has been introduced in East Africa, South America, the West Indies, the United States, Britain, and India, where it is raised as food or pets.