Jan Bartek – AncientPages.com – In North America, the tradition of constructing earthen mound structures dates back over 2,500 years, from around 1400 B.C.E. to approximately 1300 C.E. These mounds are found in a vast region stretching from Michigan down to Louisiana and vary in form from small conical shapes to large rectilinear platforms like those at Cahokia.
Additionally, there are effigy mounds shaped like mammals, reptiles, birds, and other figures. Archaeologists believe these structures served multiple purposes, including religious ceremonies, burials, and as residences for elites. In contrast, effigy mounds are rare in Mesoamerica.
Tehuacán Valley, Mexico. Credit: Luistlatoani – Public Domain
A recent study highlights a significant discovery: an ancient scorpion-shaped mound located in the Tehuacán Valley of Puebla, about 160 miles southeast of Mexico City, functioned as both an astronomical observatory and a ceremonial center.
When observed from an aerial perspective, the mound’s unique shape is clearly identifiable: it features a broad body, two extended claws, and a curved tail culminating in an elevated “stinger.” Measuring approximately 205 feet (62.5 meters) in length and constructed from stones and soil reaching up to 31 inches (80 centimeters) high, this structure has remarkably preserved its form for over a thousand years.
Recent advancements in drone photography and GPS mapping have revealed that the mound is not merely a random accumulation of field stones, as initially believed by early observers. Instead, it is a meticulously crafted effigy mound—a symbolic representation of the scorpion deity Tlahuizcalpantecuhtli. This site was first documented by researchers from the University of Texas at Austin alongside Mexico’s INAH (National Institute of Anthropology and History), dating back to between A.D. 600 and 1100—a period marked by significant agricultural innovation throughout central Mexico.
Researchers suggest that its orientation was deliberately chosen for these purposes. The scorpion deity (Tlahuizcalpantecuhtli) held great importance among ancient Mesoamerican peoples, as it symbolized Venus, or the Morning Star, in their mythology. Venus was also associated with two other deities: Tlaloc, the god of rain and water, and Quetzalcoatl, the Feathered Serpent who served as the patron deity of the Mexica/Aztec peoples.
An outline of the Scorpion Mound is shown superimposed on a drone-generated aerial photo of the feature. The prominent red line pointing northeast shows the summer sunrise azimuth (65°), viewed from the “stinger,” at the tip of the northern claw. An additional red line, on the left side of the figure, shows the sunset azimuth on the summer solstice (295°). On the evening of the winter solstice, as the green line indicates, the setting sun could be sighted by standing at the tip of the northern claw and sighting back over the feature identified as the “stinger,” with the sunset azimuth at 245°. The sunrise azimuth on the day of the winter solstice (114°) is also shown in blue. Credit: J. Neely et al., Ancient Mesoamerica (2025)
The Scorpion Mound, due to its distinctive shape and connection with water and rain, held significance within this cultural context. It was centrally located within a vast network of canal-irrigated fields covering an estimated 100 square kilometers (10,000 hectares), underscoring its potential significance in the region’s agricultural landscape.
One particularly notable aspect of the scorpion mound is its alignment with solar events, especially during the summer and winter solstices. “We estimate that on the morning of the summer solstice, if a person sighted from the ‘stinger’ (the circular ceramic cluster at the presumed end of the scorpion’s tail), the sun would rise above the tip of the northern (left) claw,” the researchers write in their study.
“The aspect of certain constellations (e.g. Venus) was used to predict seasonal changes and weather patterns. This allowed Mesoamerican societies to optimize their food production and ensure the sustainability of their communities. For Mesoamerican farmers, the summer solstice was, and remains today, an important ceremonial date and date for action, because it connotes the beginning of the rainy and planting season,” the scientists explain.
Photos of the molcajete offering. Left photo is as offering was found; right photo shows cover bowl removed. Credit: J. Neely et al., Ancient Mesoamerica (2025)
The winter solstice traditionally signified the conclusion of the season, serving as an occasion for ritual offerings and thanksgiving ceremonies. Archaeological excavations at the site uncovered various artifacts, including ceramic jars, tripod molcajetes (grinding bowls), incense burners, and fragments of hollow figurines.
A sample of ceramics collected from the field immediately south of the Scorpion Mound. Credit: J. Neely et al., Ancient Mesoamerica (2025)
These findings suggest that ritual activities were closely linked to seasonal changes. Notably, a set of “killed” tripod bowls—intentionally broken vessels—was discovered near the scorpion’s head. These contained a modern offering of tobacco and chilies, indicating that the site may have retained its spiritual importance well beyond its initial construction period.
A rendering of a to-scale sketch of the Scorpion Mound generated during our 2000 field season in the Tehuacán Valley. North is magnetic. Credit: J. Neely et al., Ancient Mesoamerica (2025)
This discovery is distinguished by evidence indicating that knowledge of solar cycles extended beyond the elite. Unlike the grand observatories such as Cacaxtla, Xochicalco, Monte Albán, Chichén Itza, and other large elite-managed Mesoamerican sites, Scorpion Mound showcases the astronomical understanding of rural farmers. It is believed that villagers, whose daily lives were intricately connected to agriculture and celestial patterns, constructed this site. The mound’s modest size and community location suggest a more egalitarian approach to sky observation, driven by practical agricultural needs and communal rituals rather than imperial control.
Images on the south and north piers in Substructure III of the Cacaxtla Palace. Note five-lobed Venus motif at the waist of each figure and the scorpion tail on the male image to the right. Credit: J. Neely et al., Ancient Mesoamerica (2025)
Archaeologists are planning further excavations to explore the construction phases of the mound and precisely test its solstice alignments using advanced instruments. If these alignments are confirmed, Scorpion Mound could serve as an important example of community-based astronomical architecture in ancient Mesoamerica.
See also: More Archaeology News
This finding highlights that sky-watching was not exclusive to temples and royalty; even small farming communities engaged with celestial phenomena, shaping their surroundings as they sought to comprehend their place within the cosmos.
The study was published in the journal Ancient Mesoamerica
Written by Jan Bartek – AncientPages.com Staff Writer