If one were to examine the penis objectively-please don’t do this in a public place or without the other person’s permission-and compare the shape of this organ to the same organ in other species, they’d notice the following uniquely human characteristics. First, despite variation in size between individuals, the erect human penis is especially large compared to that of other primates, measuring on average between five and six inches in length and averaging about five inches in circumference. (Often in this column I’ll relate the science at hand to my own experiences, but perhaps this particular piece is best written without my normally generous use of anecdotes.) Even the most well-endowed chimpanzee, the species that is our closest living relative, doesn’t come anywhere near this. Rather, even after correcting for overall mass and body size, their penises are about half the size of human penises in both length and circumference.