Junglefowl are the only five living species of bird from the genus Gallus in the bird order Galliformes, and occur in parts of South and Southeast Asia. They diverged from their common ancestor about 4–6 million years ago.
Although originating in Asia, remains of junglefowl bones have also been found in regions of Chile, which date back to 1321–1407 CE, providing evidence of possible Polynesian migration through the Pacific Ocean.
These are large birds, with colourful plumage in males, but are nevertheless difficult to see in the dense vegetation they inhabit.
As with many birds in the pheasant family, the male takes no part in the incubation of the egg or rearing of the precocial young. These duties are performed by the drab and well-camouflaged female. Females and males do not form pair bonds; instead, the species has a polygynandrous mating system in which each female will usually mate with several males. Aggressive social hierarchies exist among both females and males, from which the term "pecking order" originates.
The junglefowl are omnivorous, eating a variety of leaves, plant matter, invertebrates such as slugs and insects, and occasionally small mice and frogs.
One of the species in this genus, the red junglefowl, is of historical importance as the ancestor of the chicken, the only domesticated species. Although the grey junglefowl, Sri Lankan junglefowl and green junglefowl are likely to have also been involved.
The Sri Lankan junglefowl is the national bird of Sri Lanka.