Baculum

[3][4] The baculum arises from primordial cells in soft tissues of the penis, and its formation is largely influenced by androgens.

In the latter species, the os penis is located in the lower part of the organ and measures approximately three-quarters of an inch in length.

[42] In The Selfish Gene, Richard Dawkins[43] proposed honest advertising as the evolutionary explanation for the loss of the baculum.

[16][48][49] Strengths and weaknesses of these hypotheses were revised in a 2021 study, which also proposed an alternative hypothesis: that conspecific aggression, in combination with the development of self-awareness, may have played a role in the loss.

Along with the hominin propensity for social learning and cultural transmission, this hypothetical scenario may explain why this phenotype became fixed in all human populations.

[51] It has been argued that the "rib" (Hebrew צֵלׇע ṣēlāʿ, also translated "flank" or "side") in the story of Adam and Eve is actually a mistranslation of a Biblical Hebrew euphemism for baculum, and that its removal from Adam in the Book of Genesis is a creation story to explain this absence (as well as the presence of the perineal raphe – as a resultant "scar") in humans.

[52] In Hoodoo, the folk magic of the American South, the raccoon baculum is sometimes worn as an amulet for love or luck.

[53] Oosik (Iñupiaq: usuk or uzuk) is a term used in Alaska Native cultures to describe the bacula of walruses, seals, sea lions and polar bears.

In 2007, a 4.5 ft-long (1.4 m) fossilized penis bone from an extinct species of walrus, believed by the seller to be the largest in existence, was sold for $8,000.

[54] United States Congressman for Alaska, Don Young, was known for possessing an 18-inch walrus oosik, and once brandished it like a sword during a congressional hearing.