Discovering bones in ancient Roman quarry shafts is not unusualfinding a hand-painted dog penis bone, however, is. Bioarchaeologist Ellen Green from the University of Reading in the UK has uncovered a painted dog baculum, or penis bone, dating back over 2,000 years. Scientists found the painted bone within a first-century BCE Roman shaft in Surrey, England. Archaeologists discovered the bone among other skeletal remains, and it might have been used in fertility or good luck rituals, as first reported by Live Science. Green describes the red-stained artifact in a study published on December 25 in the Oxford Journal of Archaeology. Archaeologists discovered the 13.1-foot-deep (4-meter-deep) ancient Roman shaft (a former quarry, not the penis) in 2015 at a site called Nescot near the town of Ewell, and uncovered hundreds of human and animal skeletal remains. The researchers specifically uncovered the remains of over 280 domestic animals, including dogs, pigs, cattle, sheep, goats, and horses. Most were without evidence of butchering, disease, or burning. Of those animals, almost 200 of them were dogsbut only one of their penises was painted.Green used X-ray fluorescence (a non-destructive technique that determines an objects elemental composition) to determine that the red paint was iron oxide, a chemical compound whose color ranges from light yellow to a deep red. She then narrowed down the explanation behind the artifacts pigmentation to two scenarios: either the ochre was applied directly to the bone, staining it red, or the baculum was kept in a cloth dyed with ochre which then decomposed, staining the bone, the bioarchaeologist wrote in the study. Ochre is a natural pigment mainly composed of iron oxide.That said, no other bones appear to have been painted, archaeologists found no metal artifacts in the shaft that could have stained the bone with rust, and naturally occurring red ochre was absent from the Nescot site. As a result, Green concluded that someone intentionally painted the penis bone with red ochre before tossing it into the shaft, making it a truly special find. I could not find any other similar cases of Roman use of red ochre on bone, nor any examples from the British Iron Age, Green told Live Science. It is a very unique artifact from a very unique site, but it is ultimately a bit of a mystery. While Green describes how the bone was likely painted, many questions still remain as to why. In the study, she suggests the artifact may have been used as a ritual item, citing an already strong association between dogs and fertility within Roman Britain. Within the greater Roman world, the penis also represented good luck and protection against the evil eye, though this is the only example I could find of an actual penis having potentially been used as a ritual object, she added, according to Live Science.This claim, however, misses plenty of examples of penis bones being used in rituals across cultures. The Saami of northern Scandinavia, for example, attached bear bacula to sacred drums, while Indigenous Alaskan groups polished polar bear penis bones for knife hilts. These practices point to a wider tradition of genitalia symbolizing power, fertility, protection, and possibly even luck.The entire shaft, which was used as a burial site nine separate times over the course of about half a century after it was disused as a quarry, likely also served a broader ritualistic purpose. This is indicated by the presence of many young animals, as well as many animals born in the spring and summer, which tentatively points towards a connection with agricultural fertility, according to the study. While Green told The Independent that the idea of ritual shafts being associated with fertility is not new, it certainly brings ancient phallic symbolism to a whole new level. Maybe its time for us to replace the rabbit foot keychain.