Difficulties in Determining Origin
The biological genus Cannabis has a long, documented history of use by humans. Through archeological and historical evidence, researchers in various disciplines have been able to hypothesize a timeline of not only when Cannabis was first utilized by humans, but how it migrated with us as well. The natural history and biogeography of the genus before human utilization is hard to determine precisely, but genetic and archaeological evidence do give us a few clues as to its likely evolutionary range. Presented here is a partial summary of current scientific thought that will explain the hypothesized natural history of Cannabis, in addition to the evolution of the plant alongside humans.
Limited genetic research has been done to determine specifically where the oldest known populations of Cannabis exist and what their relationship to a common ancestor might be. Genetic research has focused primarily on whether any true speciation has occurred within the genus or whether the different “types” are just subspecies. This is difficult because the definition of a "species" can be a little squishy depending on whether you are talking to a biologist, cultivator, or a layperson. The simplest definition of a species is a population of organisms who can breed with one another and produce viable, fertile offspring. The entire Cannabis genus fits this definition, with all variations capable of breeding. This may seem to settle the issue, but another school of thought would argue that although the plants can breed, they don’t because of geographic barriers, and as a result should be considered different species despite their breeding potential. The literature is split on this topic, with some researchers proposing a single Cannabis species made up of three subspecies (sativa, indica, ruderalis) and others treating the subspecies as species in their own right. So despite the powerful tools at our disposal, there are already several questions that make determining Cannabis’ origins problematic before we’ve even started.
Then we need to tackle other issues preventing a clear picture of the Cannabis family tree. One of the first problems is the lack of fossil evidence prior to human use of the plant. Cannabis doesn’t tend to fossilize, given the locations it grows in naturally. Secondly, the characteristics that make Cannabis a relatively easy plant to grow also make it difficult to determine its point of origin; Cannabis can rapidly adapt to new regions and is an annual plant, so a high genetic diversity in a specific region is not necessarily indicative of antiquity. Even if we are able to identify “wild” Cannabis, it is most likely a “feral” variant with no real information about the ancestral type.
The result of these complications is that the best evidence to hypothesize the endemic origin of Cannabis is an examination of the ecological requirements of the plant and its reproductive strategies.
As mentioned previously, Cannabis is a relatively easy plant to grow (the nickname “weed” isn’t an accident). Cannabis will readily spread and grow without human intervention in the wild, quickly adapting to a variety of variable conditions within its range of ecological requirements. For example, the sun and heat loving Cannabis plant is more shade tolerant than other crop species, allowing for a wider range of suitable habitats. Even if we narrowed down likely origin spots based on these propagation requirements, we find that these hospitable ranges shifted several times during glacial and interglacial periods. So what do we know?
Not much.
The best hypothesis suggests that Cannabis originated in Central Asia, mostly likely within what are now the borders of China. Though this is a general consensus among many researchers, others hypothesize the location to be farther south into what is now India, Afghanistan, or even northern Eurasia.
Cannabis and Ancient Peoples
Though it’s hard to nail down exactly where Cannabis first took root, we have a better handle on the coevolution of the plant in relation to Homo sapiens. Given the ecology of the plant, its spread was inevitable. The working hypothesis is that around 10,000 years ago, most likely in central Asia, modern humans discovered the plant and found that the seeds were a valuable resource for food and oil as well as fiber for rope and eventually clothing. The oldest evidence of this use is in China where hemp fabric was discovered as well as hemp shoes that date back about five-thousand years.
We know that Cannabis thrived in close proximity to humans, even prior to the advent of agriculture. As our ancestors utilized the plant, discarded seeds readily germinated and grew around their camps and latrines, and as a result the plants followed early humans as they traversed the old world continents. It’s not surprising we curious primates would utilize the versatile weed for everyday needs of survival, but when did we notice the intoxicating effects of the plant?
Most likely the psychotropic effects of Cannabis use were discovered when the plant was burned as campfire fuel, the smoke wafting through the air and inhaled as our ancestors cooked or rested or just tried to warm themselves. Our ancestors found themselves relaxed and calmed. It allowed them to forget their aches and pains for a time. This phenomenon would have been considered a welcomed distraction from the extreme hardships early humans faced, and it’s not surprising that Cannabis, and other psychoactive substances, were often considered a gift from the gods and incorporated into religious ritual and spiritual pursuits, and eventually even recognized for their medicinal properties.
It would be nice to be able to say with certainty where the Cannabis genus first appeared, but a logical hypothesis is all we have, given the nearly ubiquitous modern distribution of the plant. Hopefully, interested parties will soon fund a more comprehensive effort to determine the plant’s origin. A few efforts that have already shed a great deal of light on many of the anthropological questions surrounding Cannabis, and more research would go a long way.
About the author
Chris DeWildt is a graduate of Grand Valley State University and Western Kentucky University. He worked in education and publishing for ten years before joining the team at Growers Network. In addition to editing the GN blog, Chris also works on the Canna Cribs series.