The domestication of plants and animals represents a profound change in human history, often referred to as the Neolithic Revolution. This period marks the transition from a nomadic lifestyle based on hunting and foraging to one centered on settled agriculture. This shift fundamentally altered the relationship between humans and the natural world, paving the way for population growth and the development of complex societies.
Domestication is a process by which humans take control of an organism’s reproduction and development. The goal is to select for traits beneficial to human needs, such as increased yield, tameness, or easier harvest. Identifying the earliest species involved in this millennia-long process reveals the foundation upon which modern civilization was built.
Defining Domestication and Its Chronology
The transition to agriculture began roughly 12,000 to 10,000 years ago, initiating a long-term process of biological change in specific species. This era saw the gradual emergence of settled communities in regions where wild resources were abundant enough to support larger, less mobile groups.
The mechanism driving domestication is selective breeding, sometimes called artificial selection, which causes genetic changes known as the “domestication syndrome.” In animals, this selection favored traits like docility, reduced flight response, and physical changes such as smaller brains or altered coat colors.
For plants, the key genetic change was the loss of natural seed dispersal mechanisms. Wild cereals possess a brittle rachis, a segment of the seed head that spontaneously shatters at maturity, scattering the seeds. Early farmers selected for a mutation that created a non-brittle rachis, meaning the grain heads remained intact until they could be harvested by hand.
This co-evolutionary process bound human societies and their chosen species together, providing a more stable food source that supported higher population densities. The earliest centers of domestication appeared independently across the globe, indicating a response to a changing post-Ice Age climate and growing human populations. The Fertile Crescent in Southwest Asia is recognized as one of the first and most influential of these centers.
The Earliest Domesticated Animals
The single earliest animal to be domesticated was the dog (Canis familiaris), an event that predates the agricultural revolution itself. The genetic divergence of dogs from gray wolves (Canis lupus) is estimated to have begun between 20,000 and 40,000 years ago in Siberia or Eurasia. The earliest definitive remains of a domesticated dog date to approximately 14,200 years ago in Bonn-Oberkassel, Germany.
Dogs were likely domesticated through a process of self-selection, where the least fearful wolves were drawn to human camps to scavenge, gradually forming a mutualistic relationship. This early companionship provided hunter-gatherers with an advantage in tracking and defense. Dogs are the only domesticated species to have spread globally with human populations while they were still nomadic.
The first livestock species, domesticated for food and fiber, were the goat (Capra hircus) and the sheep (Ovis aries). Domestication of both species occurred almost simultaneously in the Fertile Crescent region of Southwest Asia. This region provided the wild ancestors for both animals.
Goats, descended from the wild bezoar ibex (Capra aegagrus), were first managed around 10,000 to 11,000 years ago. Archaeological evidence shows an early shift in culling patterns, where more subadult males were slaughtered, indicating deliberate herding rather than random hunting. Sheep, which descended from the wild Asiatic mouflon (Ovis orientalis), were domesticated in the same area between 11,000 and 9,000 BCE.
The pig (Sus scrofa domestica), derived from the wild boar (Sus scrofa), followed shortly after, establishing a pattern of multiple, independent domestication events. Pigs were domesticated in Western Asia, approximately 10,500 years ago. A second, separate domestication occurred in East Asia, around 8,500 years ago.
The Earliest Domesticated Crops
The earliest domesticated crops in Southwest Asia are often referred to as the “Neolithic Founder Crops,” a group of eight species that laid the groundwork for farming across much of Eurasia. The most important were the cereals: Einkorn wheat (Triticum monococcum), Emmer wheat (Triticum turgidum subsp. dicoccum), and Barley (Hordeum vulgare). These domestications occurred between 10,000 and 11,000 years ago.
Einkorn wheat, domesticated from its wild ancestor, shows archaeological evidence of cultivation dating back 10,600 to 9,900 years ago. The crucial change was the genetic mutation that created a non-brittle rachis, which allowed the entire seed head to be harvested at once. This dramatically increased harvest efficiency.
Barley, domesticated around the same time as the wheats, also exhibited the non-brittle rachis trait and was a central component of the early agrarian diet in the Fertile Crescent. Its ability to tolerate dry conditions made it a reliable crop for early farmers. The earliest evidence of domesticated barley dates to approximately 10,200 to 9,550 years ago.
Beyond the Fertile Crescent, other regions domesticated their own staple crops independently. In East Asia, rice (Oryza sativa) was first domesticated in the Yangtze River basin of China, with evidence suggesting a timeline between 9,000 and 13,500 years ago. Genetic studies point to a single domestication event for all Asian rice.
In Mesoamerica, maize (Zea mays) was domesticated from a wild grass known as teosinte (Zea mays ssp. parviglumis) in the Balsas River Valley of Southern Mexico. This domestication began around 9,000 years ago, representing one of the most radical morphological transformations in plant domestication. Humans selected for a plant with soft, exposed kernels on a large cob, unlike its wild ancestor whose seeds were small and encased in hard shells.