PENIS SIZE AND SPERM VELOCITY: ALL IS NOT EQUAL IN THE DARK?
In terms of penis dimensions and sperm velocity within the field of zoology, specifically within bat populations, researchers established a link between two physical attributes pertaining to male bat genitalia. They were penis size and sperm velocity. Researchers found, that in male bats, penis head width correlated with sperm velocity which prompted the researchers to suggest that penis shape might act as a marker of male fertility. Of course, these are animals who literally have to “screw on the fly” and so there may be genetic advantages when it comes to sperm velocity and penis length in terms of “wrangling” a fisty female in the treetop canopy. This started to tantalized my imagination with questions like, “How might this correlate to the penis attributes in cheating men?” That is, in some men who literally “screw on the fly.” Well, there has been no research conducted as of yet, and so, it is with great disappointment I can offer no comparisons between human males and their penis size, sperm velocity, and active past history when copulating with a diverse population of females. Well, not at least at this present time.
It has long been recognized that the impressive diversity of male genitalia among animal taxa emphasized that organs related to copulation have evolved faster than any other traits and many of these evolving physiological characteristics have strengthened reproductive barrier and speciation processes. Current scientific opinions tend to agree that sexual selection drives diversification as penis shape could first evolve through female selection during post-copulatory competition. Men with desirable penis attributes would thus gain an advantage in winning favor against concurrent suitors (thereby displacing competitor male ejaculate). The morphology of male bat genitalia may further become entangled in a sort of genital arms race when female interests differ from those of males and sexual conflicts arise. Large penises could also be evolutionarily selected when female genital tracks have to be reached from a distance. Thus, contributing to penis shape and length. For flying mammals, this could pose a real problem and anyone who has ever watched nature shows know that “screwing on the fly” is a real challenge in the natural world. Thus, an elaborate penis may then contribute to extending copulation duration by locking the female genitalia and reducing the female capacity to re-mate with another male within a certain period of time. (Here I’m thinking when two animals become locked together after copulation, becoming unable to separate because of the male’s elaborate shape and penis size). Specific penis shapes or copulatory behaviors could also be selected for by females, as a way of being honestly informed about the good genes or fertility of their partner. This would enable mechanisms involved in cryptic female choice to shape the collective male genital gene pool and facilitate evolutionary mechanism with regard to desired size and shape. The most important contribution of this research: “It would seem reasonable to assume that penis size and its scaling to body size should be sexually selected for” since penises that sexually stimulate female genitalia in a pleasurable way would most likely be selected again after initial copulation thereby displacing the less desired males’ genetic contributions. In human comparison it would be the difference of say, Magic Johnson having sexual intercourse with a 3" midget as opposed to two partners of relatively the same size, shape, and length. How stimulating could the sexual encounter be when significant allometric differences are involved? The researchers noted that when uncovering the difference regarding penis size and shape in male bats the steep allometric slop representing large penises were disproportionally large in large individuals.
In the study of the relative growth of male genitalia of an organism, in relation to the growth of its whole body, insect, and spider species have been by far better researched than any other taxonomic group. At first glance, mammalian genitalia conforms to the general trend, with less than a quarter of the species exhibiting an allometric slope greater than 1 (meaning, less than 25% of male mammals are well endowed with a large penis shape and size in comparison to whole-body size). Furthermore, penis length has only been analyzed in a handful of studies. Which means, no word about its evolutionary purpose in humans. A crucial point that arises with regard to the genetic distribution of size and shape in human male genitalia is the fact that only wealthy men may actually have any chance of contributing any significant portion of their genes to genetic diversity, as wealth promotes prolific breeding patterns granting a better chance at increasing the genetic distribution of an individual’s genes. The Ancient Egyptian Pharaoh Ramesses II is an excellent example of this. Ramesses II had a large number of children. The largest of any Egyptian Pharaoh. He sired between 48 to 50 sons and 40 to 53 daughters. That is between 88 and 103 children. His genetic trait contribution, including penis length, would have made an excellent genetic research study in terms of his individual genealogy. Most human men do not have large numbers of offspring and so, in humans, large penis size is left to the luck of the draw. But still, I like to imagine my past promiscuous ex-boyfriends, you know the ones who are devilishly handsome, charmingly witty, and who screw anything that moves behind your back, swinging from branch to branch, in some pre-historic lush jungle endowed with a phallus large enough to copulate anything from a distance.
