Author : Wahid Ahmad
From the ancient
landscapes of Southeast Asia to the bustling markets of Mesopotamia, the
history of how chickens transformed from wild counterparts to our feathered
companions is an intriguing story woven with mystery and adaptation.
The history of chicken
domestication and its spread has been debated. Some believed chickens
originated in Southeast Asia or South India, while others argued for a northern
Chinese origin. Early claims of chicken bones in the Indus Valley and northern
China were questioned.
Recent studies reevaluated
these claims. Bones from the Indus Valley were deemed inconclusive or possibly
from local wild fowl. Northern China's supposed chicken bones were identified
as pheasants, and climate records suggested unsuitable habitat for red
junglefowl.
Divergence from Wild Varity
Genetic studies suggest
that domestic chickens mainly descended from red junglefowl, specifically the
subspecies called Gallus gallus spadiceus in Southeast Asia. The genetic
divergence between these chickens and their wild counterparts occurred between 12,800
and 6,200 years ago, but this doesn't necessarily represent the start of
domestication. It marks the split between the wild and domestic chicken
lineages.
Reanalyses indicate that
the first chickens likely came from the subspecies Gallus gallus spadiceus in
southwestern China, northern Thailand, and Myanmar. The earliest confirmed
chicken bones date back to around 1650-1250 BCE in central Thailand. Chickens
then spread to Central China, South Asia, and Mesopotamia by the late second
millennium BCE, reaching Melanesia by 700 BCE. Their western dispersal to
Ethiopia and Mediterranean Europe was notably rapid.
The red junglefowl are
often called "bamboo fowl" in Southeast Asian languages, in the
native range these birds take advantage of cyclical bamboo flowering and
seeding events. Red junglefowl also consume rice, a staple for Southeast Asian
domestic chickens. As Neolithic communities in Southeast Asia adopted mixed
foraging and cereal cultivation, such as cultivating rice and millet, the
habitat changes attracted red junglefowl to human settlements.
How and When
The transition from
primary forest to secondary vegetation due to land reclamation for cereal
cultivation created a more suitable habitat for red junglefowl. They thrived in
slash-and-burn agricultural systems, and the presence of cultivated fields,
fallow fields, cereal harvest residues, and other human activities likely
attracted them to villages. The availability of cereals created selective
pressures, leading to changes in red junglefowl behavior over multiple
generations, such as a relaxation of selection against larger clutch size and
decreased territoriality in males.
Archaeobotanical evidence
suggests that rice cultivation sites within the distribution of the likely
chicken progenitor, Gallus gallus spadiceus, appeared around 2000 BCE in
southern Yunnan and northeast Thailand. While cereal farming was present,
there's no early evidence of domestic chicken populations. In interior zones
with rainfed rice and millet cultivation, a closer relationship between people
and red junglefowl is evidenced by early chicken bones at sites like Ban Non
Wat and Non Nok Tha. In regions north of Yunnan, wet rice agriculture appeared
as early as 4000 to 3000 BCE, but chickens only appear around 1000 BCE, indicating
a delayed association between chickens and wet rice cultivation compared to
other forms of cultivation in the tropical south.
Spread
The spread of chickens
aligns with the development of agriculture across Asia and Africa. In South
Asia, sedentism and the dominance of domesticated rice, wheat, barley, and
other grains became prevalent in the Ganges plains around the second millennium
BCE. This period, especially from the later second millennium BCE, corresponds
with the arrival of unequivocal chicken remains in the Indian subcontinent. The
introduction of domesticated indica rice around 1600-1500 BCE in the Upper and
Middle Ganges, with its rainfed and fallow features, likely attracted chickens.
Genomic evidence indicates that local domestic chickens in South Asia resulted
from the mixing of local Gallus gallus murghi with introduced chickens from Gallus
gallus spadiceus.
In Iron Age Mesopotamia,
the cultivation of Chinese millets intensified after 1000 BCE, coinciding with
the archaeological visibility of poultry farmingallus Irrigated rice also
became established in Syria by around 1100 BCE, aligning with the broader diversification
of grain crops and the emergence of poultry husbandry after the late Bronze Age
collapse.
In Africa, the appearance
of chickens correlates with the spread of rice agriculture. The
eighth/ninth-century CE translocation of chickens to coastal Southeast Africa
and Indian Ocean islands aligns with the introduction of Asian crops like rice.
In the Niger Basin, archaeological evidence shows increased urbanism and
widespread rice cultivation around 300-900 CE, coinciding with the first
appearance of chickens in the region.
Early pictures and chicken
remains in Mesopotamia and parts of Europe suggest chickens were linked with
elite culture, special burials, holy places, and divine ceremonies. New
discoveries show that early European chickens were respected, not eaten right
away. However these findings need further validation. Top of Form
In conclusion, chickens'
domestication and global spread from red junglefowl occurred relatively late
compared to other farm animals. Further archaeological investigations may
unveil earlier human-junglefowl connections and global chicken translocations.
The allure of rice and
millet agriculture was pivotal in domestication, creating favorable habitats in
extensive cultivation systems and sustaining larger bird populations in
intensive rice farmingallus Grain cultivation, attracting various birds,
initiated a commensal relationship with red junglefowl, leading to
domestication.
Biologically, rice and
millet cultivation supported chicken husbandry in subtropical regions, while
their adaptability and granivorous diet suited agriculturalists in arid and
temperate areas. The gradual integration of chickens in colder climates
suggests a slow adaptation to these environments.
In essence, the journey of
chickens invites us to see them as more than domesticated animals, but as
agents of change, adapting across diverse landscapes and cultures. The evolving
bond between humans and chickens, woven into our shared history, promises
ongoing revelations through continued archaeological and scientific exploration.
References:
https://doi.org/10.1073/pnas.2121978119