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Massive Native American drawings – which remained unseen in an Alabama cave for more than 1,000 years – have been unveiled by a team of scientists. It’s the largest known cave art ever discovered in North America.

The art was practically invisible until researchers investigated the cave and used 3D scans to reveal the works, including one stretching for 11 feet (3.4 meters) in length. A study detailing their findings published Tuesday in the journal Antiquity.

The large artwork was discovered inside 19th Unnamed Cave in Alabama, which has been kept anonymous to protect the site from vandalism. Although its location was first found in 1998, the tight confines of the cave made the sprawling art, drawn in mud, impossible to see, so it was missed. But hundreds of smaller images were discovered throughout the cave at that time.

This tall humanlike figure appears to be wearing a complex costume.

The giant glyphs may depict spirits of the underworld and have been dated to the first millennium AD. The art was created precontact, or prior to the Native Americans encountering outside cultures, according to the study.

Jan F. Simek, a distinguished professor of science at The University of Tennessee, Knoxville, and a team of researchers initially stumbled upon the giant drawings while working on documenting the cave interior beginning in 2017.

“We knew the cave contains precontact Native American mud glyphs, and we were carrying out a 3D photogrammetry documentation project to aid with management and conservation,” Simek, lead study author, said. “The very large cave art images cannot be seen in person in the cave because of the constrained spaces on the site.”

The photogrammetry process involves taking thousands of photos to create a 3D model of something. It produced an accurate record of the site, but had the added benefit of unveiling the secret artwork – especially given the cave’s very low ceilings. During two months of field work, the team took 16,000 photographs.

During the 3D imaging sessions, the team captured a wide view of the ceiling beyond where sunlight reaches in the cave and found five previously unknown drawings.

Mysterious figures

Using photogrammetry in this cave and at other sites could change the way scientists discover and understand Native American cave art, including the intentions and meanings behind the designs.

The researchers were able to virtually manipulate the cave ceiling using their model to study the glyphs in detail and create digital drawings based on the crosshatching patterns. Four of the artworks show humanlike figures wearing elaborate outfits.

One “remarkable human figure” has a long body with extended arms and rounded shoulders. It sports a complicated design across the torso made up of different styles of lines, which likely suggests a type of garment or regalia, according to the researchers. Lines trail behind the figure, suggesting a sash, and another line appears to show the figure symbolically emerging from the rock.

This enigmatic figure is largely composed of swirling lines, with a round head at one end and a possible rattlesnake tail at the other.

Another figure has a square head with lines extending from the top, a rectangular torso and a single leg. Several of the figural depictions show a type of pattern or sash on the torso. One has a triangular head with ovals emerging from either side, which looks similar to “an animal head with pricked ears,” but hands that look “clearly human.”

A separate figure is made of multiple twisting and curving lines and has a tail that looks like that of a rattlesnake, but the researchers “do not know what it represents.”

The fifth, and largest, figure appears to be a diamondback rattlesnake with clear patterns similar to the eastern diamondback rattlesnake. From head to tail, it measures 11 feet (3.4 meters).

The diamondback is the largest rattlesnake found across the Americas, and it was sacred to Indigenous people living in the US Southeast.

The inspiration for the figures depicted remains a mystery.

“As we have not seen their like before, we do not know the identity of these ancient cave art anthropomorphs,” the researchers wrote in the study. “They are not recognisable characters from ethnographically recorded Southeast Native American stories, nor from archaeologically known iconographic materials.”

But the figures do share spiritual themes – like figures exhibiting supernatural characteristics – with other known rock art in the region, so they may show characters from “previously unknown religious narratives, likely of the Middle Woodland period” between 200 BC and 600 AD.

This serpentlike figure has a round head and diamond-shaped body markings that suggest it's a diamondback rattlesnake.

Perhaps the most intriguing aspect is how the artwork was created. Although the entrance is 32.8 feet (10 meters) high and 49.2 feet (15 meters) wide, the chamber containing the art has a low ceiling only 1.9 feet (0.6 meters) from the cave floor. This means whoever created the art had to crouch or crawl through the chamber – and the drawings can only be viewed by lying on the cave floor.

“They are so large that the makers had to create the images without being able to see them in their entirety,” the researchers wrote. “Thus, the makers worked from their imaginations, rather than from an unimpeded visual perspective.”

Secret symbolism

The artwork was created during a time when Indigenous tribes were shifting away from being foragers and turning to farming and building long-term settlements.

These tribes used their surroundings to honor their religious and spiritual beliefs, building mounds as routes for spirits to reach the upper world and using caves as sacred spaces that served as routes to the underworld.

“We know that Native Americans modified their landscapes on very large scales in order to connect the living with the natural and supernatural worlds and to the varied elements of those worlds,” the researchers noted in the study. “The large figures drawn in 19th Unnamed Cave therefore probably represent spirits of the underworld, their power and importance expressed in their shape, size and context. They were elements in the broader sacred spiritual landscape of pre-contact Native Americans.”

Smaller mud glyphs show a) a coiled serpent figure, b) wasp, c) stylized bird and d) anthropomorphic figure surrounded by swirling lines.

While this creation is similar to large open-air rock art found in Utah and other locations across North America, it’s unusual to find such large drawings hidden away in a cave, which is why their presence was entirely “unsuspected.”

The first North American cave art was found in Tennessee in 1979 and was 750 to 800 years old. Since that initial discovery, 89 other sites have been found across southeastern North America. The oldest site dates back 7,000 years, but much of the cave art was created between 800 and 1600 AD.

Although the 19th Unnamed Cave has been well studied, researchers think they may just be getting started, since these cave drawings were previously missed. But the cave includes more than 3.1 miles (5 kilometers) of underground passages.

“(The) 19th Unnamed Cave is the richest of all known cave art sites in south-eastern North America,” the researchers said.

“These images are different than most of the ancient art so far observed in the American Southeast and suggest that our understanding of that art may be based on incomplete data,” Simek said.

Top photo: An anthropomorphic figure depicted in the cave art appears to be wearing some sort of patterned clothing and sash while standing on one leg.