Humans and cannabis have shared an intertwined journey for thousands of years. As early humans migrated across continents, they carried cannabis seeds and knowledge with them, and in turn the plant adapted to new lands and uses. This co-evolutionary relationship—where human cultivation shaped cannabis genetics, and cannabis influenced human culture—has left a lasting legacy on both the plant and our societies. From its earliest domestication in East Asia over 10,000 years ago, cannabis spread alongside trade routes and human settlements, evolving from wild grassland weed into a domesticated crop valued for fiber, food, medicine, and ritual. Over millennia, people selectively bred cannabis for traits that fit their needs: tall fibrous stalks in one region, or resinous intoxicating flowers in another. These ancient cultivation practices gradually diverged the plant into distinct populations. By the classical era, observers already noted different “kinds” of cannabis, foreshadowing what we later called sativa and indica. In short, human migration and agriculture drove cannabis from a humble Asian herb to a global botanical companion, with each new region leaving its genetic imprint on the plant.
The history of cannabis is a tale of human migration. Early Domestication in Asia: Modern genomic research indicates that Cannabis sativa was first domesticated in East Asia during the early Neolithic period. Archaeological evidence from China suggests cultivation as far back as 12,000 years ago, making cannabis one of humanity’s oldest cultivated crops. Initially, ancient farmers grew cannabis mainly for its strong fiber (hemp) and nutritious seeds. In these early East Asian landraces, humans unintentionally selected plants with taller stalks and low resin content, ideal for rope and cloth. From China and Mongolia, cannabis seeds traveled with migrating tribes and traders. By around 2000–1500 BCE, coastal farmers had brought cannabis to the Korean peninsula, and Indo-European groups (the Aryans) introduced it to the Indian subcontinent.
Emergence of Drug-Type Cannabis: In South Asia, cannabis found a new purpose. The warm climate and cultural practices in India encouraged use of cannabis for its psychoactive resin. By 1000 BCE, Indian traditions (as recorded in Sanskrit Vedic texts) celebrated ganja and bhang (forms of cannabis) as sacred herbs for relieving anxiety and aiding meditation. Humans in this region began favoring plants with more potent resin (rich in THC). This selection pressure produced the classic “drug-type” cannabis: tall, lanky plants with narrow leaflets and abundant psychoactive flowers. In contrast to hemp, these South Asian landraces developed a chemistry oriented toward THC rather than CBD, an adaptation that may have been advantageous in tropical sun and poor soils. Thus, ancient farmers in India effectively bred what would later be termed “sativa”-type cannabis—although at the time it was simply the local variety suited for producing intoxicating hashish and medicines.
Diffusion to the Middle East and Africa: From its Asian heartlands, cannabis journeyed westward. Nomadic Scythians carried cannabis across Central Asia and into the Middle East by around 1000–500 BCE. Herodotus famously recorded Scythian tribes throwing hemp seeds on hot stones and inhaling the vapors in ceremonial tents, indicating the plant’s early ritual use on the steppes. Through overland and maritime trade, cannabis reached the Middle East and North Africa in antiquity. It was known in ancient Egypt and Persia, though primarily for fiber and medicine. By the early centuries CE, the spread of Islam played a role in cannabis diffusion: Arabian traders and Sufi mystics propagated the use of hashish (cannabis resin) across the Islamic world. By the 7th–13th centuries, cannabis was cultivated in Syria, Lebanon, Egypt, and Morocco, adapting to arid climates and giving rise to local varieties used for hash production.
Crucially, there appear to have been two distinct ancient influxes of cannabis into Africa. The first was via North Africa and the Mediterranean: Cannabis indica likely entered Egypt and Maghreb regions by the Classical or early medieval period. This was the broadleaf, resinous variety from Central/South Asia. Over time, North African farmers developed their own landraces (for example, kif traditions in Morocco) well-suited to dry, sun-baked conditions. A second wave came via the Indian Ocean: Between roughly 500–1000 CE, seafarers from India carried cannabis to East Africa via Madagascar trading routes. Indian Hindu traders and travelers introduced cannabis (and the practice of smoking it) to places like Ethiopia, Kenya, and eventually South Africa. The plant thrived in African soils, and local populations embraced it for spiritual and medicinal use. As cannabis took root in sub-Saharan Africa, each region imparted unique environmental pressures. For instance, in equatorial East Africa and Southern Africa, the intense sun and shorter daylengths encouraged strains with quick flowering cycles and tall, airy growth. These African landraces were predominantly psychoactive (dagga became a common term), and they spread inland via indigenous trade routes.
European Hemp and Global Dissemination: Meanwhile, in Europe, cannabis primarily meant hemp. Starting from at least the Iron Age, Europeans grew hemp for rope, sails, and textiles. By the Middle Ages, hemp was a strategic resource, so important that many European powers mandated its cultivation. Although psychoactive use in Europe remained limited (and often frowned upon), the familiarity with hemp made cannabis seeds a standard item carried on long voyages. During the Age of Discovery (15th–17th centuries), European colonizers brought hemp to the New World and other colonies. The Columbian Exchange saw Spanish and Portuguese settlers planting hemp across the Americas for naval rope and canvas. For example, the Spanish grew hemp in Chile in the 1500s, and the British later farmed hemp in Canadian and Virginian colonies. These introduced populations were non-intoxicating hemp varieties (high-CBD, low-THC) descended from European and Chinese landraces. They represented the Cannabis sativa subsp. sativa gene pool and were distinct from the drug-type gene pool of indica subspecies varieties.
However, a very different vector carried drug cannabis into the Americas: the transatlantic slave trade. Enslaved Africans from regions like Angola and the Congo secretly brought cannabis seeds with them to Brazil and the Caribbean in the 16th and 17th centuries. Accounts note that slave women braided cannabis seeds into their hair or hid them in dolls, ensuring their cherished plant would accompany them in the new world. Once in the Americas, these seeds germinated in tropical soil, and cannabis cultivation by enslaved peoples became an act of sustenance and cultural preservation. In Portuguese Brazil, planters observed the African slaves growing “maconha” (cannabis) in their gardens and smoking it in pipes. The strains introduced this way were likely West and Central African landraces—robust, heat-tolerant sativas that had adapted to equatorial climates over centuries. They flourished from the northeast of Brazil to as far as the Amazon basin. Similarly, on British and Spanish Caribbean islands, enslaved and indentured peoples grew cannabis. The plant came to be called ganja in the British West Indies after 19th-century indentured laborers from India arrived (more on that in the Jamaica section). By the 19th century, psychoactive cannabis had quietly spread throughout Latin America and the Caribbean, even as colonial authorities sporadically tried to suppress its use among the underclasses.
In summary, human migrations, whether voluntary (traders, explorers) or forced (slaves, laborers), carried cannabis to every inhabited continent by the modern era. Each migration event was also a genetic dispersal: seeds from Asia and Africa found new homes and intermingled with local varieties. Crucially, human cultivators did not just passively transport cannabis—they actively domesticated it in each locale. Through saving seeds from the best plants and adapting farming methods, people imprinted their preferences on local cannabis gene pools. Over generations, this led to distinct regional varieties optimized for local climates and uses. For example, cultivating cannabis in the Himalayas of Afghanistan or Pakistan favored compact bushes that finished flowering before autumn frosts, whereas growing it in Thai jungles rewarded plants that could handle year-round equatorial daylight and humidity. Human selection for such traits over centuries is why an Afghan charas plant looks and behaves so differently from a Thai ganja plant. Yet all are members of the same species—Cannabis sativa—shaped into divergent forms by geography and human culture.
Ren G, Zhang X, Li Y, et al. Large-scale whole-genome resequencing unravels the domestication history of Cannabis sativa. Science Advances. 2021;7(29):eabg2286. doi:10.1126/sciadv.abg2286.
Clarke RC, Merlin MD. Cannabis: Evolution and Ethnobotany. University of California Press; 2013.
McPartland JM, Hegman W, Long T. Cannabis domestication, breeding history, present-day genetic diversity, and future prospects. Critical Reviews in Plant Sciences. 2019;38(4):327-352.
Merlin MD. Man and Marijuana: Some Aspects of Their Ancient Relationship. Fairleigh Dickinson University Press; 1972.
Warf B. High Points: An Historical Geography of Cannabis. Geographical Review. 2014;104(4):414-438.
Abel EL. Marihuana: The First Twelve Thousand Years. Plenum Press; 1980.
Sensi Seeds. Cannabis in Angola – Laws, Use, and History. Sensi Seeds blog. Published 2019. Accessed May 2025. (Documentation of Angolan slaves introducing cannabis to Brazil in 16th century.)
Leafly. Jamaica’s Cannabis Roots: The History of Ganja on the Island. Leafly News. Published 2018. Accessed May 2025. (Details on indentured Indians bringing cannabis to Jamaica and the term “ganja.”)
Olivastu. Cannabis Landrace Strains – Origin and Complete Strain List. Olivastu Olipedia. Published 2021. Accessed May 2025. (List of notable landrace strains by region and traits.)
Veriheal. Cannabis and the Mystical Tale of the Hippie Trail. Veriheal Blog. Published April 13, 2021. Accessed May 2025. (Discussion of how hippie travelers collected landrace seeds from Asia in the 1960s–70s and spread them globally.)