Serpent Mound, located in Ohio in the United States, is an enormous earthwork built on a grassy plateau above Ohio Brush Creek. It is one of many large earthworks in North America, but it is unusual in representing an image when seen from above. This image has been interpreted as a snake swallowing an egg.
The date of construction is uncertain, but recent research suggests that Serpent Mound was created in the last few centuries CE when the river valleys west of the central Appalachian Mountains were occupied by a people known to modern archaeologists as the Adena culture. We have no way of knowing what they called themselves. The Adena were a sophisticated culture at the center of a trade network stretching north beyond the Great Lakes south to the Gulf of Mexico. One of the distinctive features of their culture was the construction of large earthworks, many of which served funerary purposes, but may also have marked ceremonial centers or areas for gathering and trade.
Serpent Mound is similar in construction to other Adena earthworks, but unusual in its imagery. Partly for this reason and partly on the basis of charcoal found at the site which was dated by radiocarbon to approximately 1000 CE, Serpent Mound was once believed to be the work of the much later Fort Ancient culture. Recent reexamination, however, has indicated that the charcoal was left by later peoples who may have rebuilt parts of Serpent Mound, but that the original construction probably goes back to the Adena people.
The function of Serpent Mound is unclear. It was not a burial site like many Adena earthworks, nor does it appear suitable as a gathering site or market. There are some aspects of the site, though, that suggest possible purposes.
For one thing, there are numerous cosmic connections. The layout of the serpent resembles the constellation Draco and various shapes of the serpent’s body align with the solstice and equinox sunsets. There are a number of interesting geographical features of the location as well. The mound stands on a plateau at the top of a cliff above a creek which divides an area of hilly land to the east from a flatter area to the west. The bedrock of the area is also folded in unusual ways as a result of a prehistoric meteorite impact.
The imagery of the serpent and egg is also suggestive. We know very little about the mythology or beliefs of the people who built Serpent Mound, but the combination of snakes and birds is a motif that occurs in the mythology of peoples around the world. The Aztecs believed that the sight of a serpent fighting an eagle marked the place where their ancestors founded the city of Tenochtitlan. In Norse legend, an eagle sits at the top of Yggdrasil, the world tree, while a serpent gnaws at its roots. In Hindu and Buddhist tradition, the great bird Garuda wars with the naga, a race of snake spirits.
The bird/snake opposition may represent a sky/earth or a sun/moon opposition. Birds, as flying creatures, stand for the sky and sun that travels across it. Snakes may stand for the earth since many snakes burrow into the earth during the winter or for the moon, since snakes are renewed by shedding their skin in the same way that the moon renews itself monthly by going through it phases. In either case, the symbolism has a cyclical and cosmic significance that fits with the astronomical associations of Serpent Mound. The image of the snake swallowing the egg might be a symbol of the cycle of seasons marked out by solstices and equinoxes.
Accurately tracking the changing seasons is essential to any agrarian society. Serpent Mound might have been a celestial observatory for marking the progress of the year and timing the work of sowing, harvest, hunting, and commerce. Even if it had such a function, the monumental size and unusual location of the feature imply that its symbolic importance was at least as meaningful. The position of the earthwork on top of a slope above a river and a stretch of flatter ground would have made the site highly visible. Like the pyramids of Egypt, the sight of it would have been a reminder to those approaching the core Adena lands of the power that the Adena leaders wielded.
Thoughts for writers
Breadth is as importance as depth in doing your research. No matter what your topic, you are going to come across gaps. Some gaps are small, like the missing minutes of Nixon’s Oval Office tapes. Others are so vast that entire civilizations disappear into them. So much evidence has been lost that the amount of history that we know and understand is absolutely dwarfed by what we don’t.
The function of Serpent Mound is just such a gap, and when you come across a gap like this, one of the things that can help you try to fill it is a broad knowledge of other cultures. We may not know what the image of a serpent swallowing an egg meant to the Adena people, but we have some idea of what similar imagery meant to other peoples. That gives us at least a few ideas to start with in trying to make sense of Serpent Mound.
At the same time, we always have to be cautious with this kind of thinking. We can make reasonable guesses about Serpent Mound, but reasonable guesses aren’t always right. Studying history also means being comfortable with uncertainty and respecting the line between evidence and theory.
This is what we’re like as humans: we tend to do the same things over and over again, just in different forms. The variety of those forms can be incredible and astounding, but at base there are a limited number of things that are really important for a society to do. You need food and water, clothing and shelter. You need social structure and ideas around which people can organize their lives. You need to be able to cope with both natural and human-made disasters. Different people do the same things in different ways, but if you understand one people’s way of doing things, that gives you a place to start in understanding another’s.
History for Writers is a weekly feature which looks at how history can be a fiction writer’s most useful tool. From worldbuilding to dialogue, history helps you write. Check out the introduction to History for Writers here.
Co-Geeking 
