The Red Junglefowl (Gallus gallus) is a tropical member of the Pheasant family, and is widely believed to be a direct ancestor of the domestic chicken. Recent research suggests possible hybridisation with the Grey Junglefowl.
It was first raised in captivity at least several thousand years ago in the Indian subcontinent, and the domesticated form has been used all around the world as a very productive food source for both meat and eggs.
The range of the true species stretches from northeast India (where the pure species has almost certainly been diluted with cross breeding from domestic breeds) eastwards across southern China and down into Malaysia, The Philippines and Indonesia. Junglefowl are established on several of the Hawaiian Islands, but these are feral descendents of domestic chickens. They can also be found on Christmas Island and the Marianas.
Each of these various regions had its own subspecies. Some examples include:
G. g. gallus Indochina
G. g. gallus bankiva Java - Bankiva Fowl
G. g. gallus jabouillei Vietnam
G. g. gallus murghi India
G. g. gallus spadiceus Burma (considered by some the true ancestor of the domestic bird)
G. g. gallus domesticus (Chicken)
Male and female birds show very strong sexual dimorphism. Males are much larger; they have large red fleshy wattles and comb on the head and long, bright gold and bronze feathers forming a "shawl" or "cape" over the back of the bird from the neck to the lower back. The tail is composed of long, arching feathers that initially look black but shimmer with blue, purple and green in good light. The female's plumage is typical of this family of birds in being cryptic and designed for camouflage as she alone looks after the eggs and chicks. She also has no fleshy wattles or comb on the head.
During their mating season, the male birds announce their presence with the well known "cock-a-doodle-doo" call. This serves both to attract potential mates and to make other male birds in the area aware of the risk of fighting a breeding competitor. The lower leg just behind and above the foot has a long spur for just this purpose. Their call structure is complex and they have distinctive alarm calls for aerial and ground predators to which others react appropriately
Males make a food-related display called 'tidbitting', performed upon finding food in the presence of a female. The display is composed of coaxing, cluck-like calls and eye-catching bobbing and twitching motions of the head and neck. During the performance, the male repeatedly picks up and drops the food item with his beak. The display usually ends when the hen takes the food item either from the ground or directly from the male’s beak and is associated with copulations and more offspring. They are omnivorous and feed on insect, seeds and fruits including those that are cultivated such as those of the oil palm.
Behaviour, not morphology, is the best predictor of paternity. Specifically, behaviours related to dominance and to signalling are critical, and the single best predictor is the rate at which males produce anti-predator alarm calls. This suggests that male alarm calling is a form of mate investment, increasing the survival of his chicks.
Flight in these birds is almost purely confined to reaching their roosting areas at sunset in trees or any other high and relatively safe places free from ground predators, and for escape from immediate danger through the day.
The pure form is quite rare and may even be extinct, only represented in the wild by birds with various degrees of back crossing with domestic selections of the species.
The other three members of the genus — Sri Lanka Junglefowl (Gallus lafayetii), Grey Junglefowl (Gallus sonneratii), and the Green Junglefowl (Gallus varius) — do not produce fertile hybrids with the Red Junglefowl, suggesting that it is the sole ancestor of the domestic chicken. However, recent research has revealed the absence of the yellow skin gene in the wild Red Junglefowl found in domestic birds, which suggests hybridisation with the Grey Junglefowl during the domestication of the species.