Archive for Scientific American

The Secrets Behind Penis Shape and Vigorous Sex

Posted in Science with tags , , , , , , , on June 25, 2009 by neandergal

No, these secrets have nothing to do with the sexual prowess of the new found love of your life, but a human evolutionary process that gives rise (no pun intended) to the shape of the human penis today.

An article, Secrets of the Phallus: Why Is the Penis Shaped Like That? in Scientific American by Jesse Berring gives us an explanation of why the shape of the penis is the way it is today and how its anatomy plays a role in reproductive success by displacing sperm in the vagina placed there by other mates. The process is known as the “Semen Displacement Theory.”

The “head”, otherwise known as the glans penis acts as a plunger that sucks out semen possibly placed by a competitor. Those mates equipped with a better “plunger” stood a better chance of displacing another male’s semen and therefore more chance of passing on their genes. The article refers to a behavioral study that shows how sex is more vigorous if a mate suspects infidelity. More vigorous and deeper penetration also means more semen displacement.

Another revelation is how the post ejaculatory sleepy affect acts as prevention against the possibility of “self-displacement of semen” by a second helping of subsequent sex. The refractory period plays a part in reproductive success by acting as a mechanism for avoiding self displacement of semen and gives sperm time to reach an ovum. If you are too tired and temporarily impotent to engage in a second helping soon afterwards, there is less chance of displacing semen and therefore more chance of impregnation.

In other words, the evolutionary process is most definitely involved in the shape of things to come, in a manner of speaking.

A Most Bizarre Sex Act

Posted in Science with tags , , , , , , , , on May 24, 2009 by neandergal

Spiders weave a tangled sexual web that leads to stiffer competition for passing on their genes. Scientific American reports on a recent study published in the May 2009 issue Evolution that shows how the genitalia of Nephilid and Golden Orb Weaver spiders evolved from simpler to more complex structures.

Male spiders that had more hooks, ridges and twists on their palps stood a greater chance of passing on their genes then their less complex competitors. When the male copulates with the female, the palp breaks off inside the female so there is a greater chance of his sperm fertilizing the female’s eggs. He is not only content from giving her his all, but will stick around her web and chase off any competitors. Female ducts evolved from those that gave straight easy access to more convoluted ducts with twists and turns making it harder for penetration by males lacking the right equipment.

Monkeys Hate Others’ Bonuses, Too

Posted in Science with tags , , , , on February 17, 2009 by neandergal

A report in Scientific American tells how primatologist Frans de Waal during the annual meeting of the American Association for the Advancement of Science explains that even monkeys know when they are being screwed.

It’s a shame the rest of us do not seem to know until it’s too late… Welcome to “Cucumberland.”

Warning! Please do not bend!

Posted in Science with tags , , , , on January 24, 2009 by neandergal

The article, Ouch! Can You Really Break Your Penis? published in Scientific American warns that men who engage in bedroom acrobatics can seriously damage their tunica albuginea. Aiming for your target under momentum such as in a run and jump can result in penile fracture if you miss. This is indeed what happened to “this patient who suffered penile fracture after running across the room and trying to penetrate his wife with a flying leap.”

The tunica albuginea is a layer of connective tissue that surrounds each of the two tubes of corpora cavernosa and testis. The corpora cavernosa is the spongy tissue that engorges with blood causing an erection. Bending the penis suddenly under pressure can break the tunica albuginea causing bruising and needless to say, loss of erection.