Discoblog » Sex & Mating

Answered: All Your Nagging Questions About Testicle Location

Andrew Moseman — Fri, 20 Nov 2009 20:45:48 +0000

As you’ve probably heard, a man’s testicles hang down because sperm are hyper-sensitive to temperature and need to be a little cooler than the inside of the body. But isn’t there more to it than that?

Oh, definitely yes, says research psychologist Jesse Bering, writing for Scientific American. Bering goes on at great length in his analysis of testicular location. Sure, he argues, the temperature part makes sense. But why would natural selection, which so rewards passing on your genes, put a man’s means of passing on those genes in such a terribly exposed place on his body?

Bering’s lengthy account of gonad geography, and the studies trying to explain it, includes some real gems:

One of the more fanciful accounts–and one ultimately discarded by the authors–is that scrotal testicles evolved in the same spirit as peacock feathers. That is to say, given the enormous disadvantage of having your entire genetic potential contained in a thin satchel of unprotected, delicate flesh and swinging several millimeters away from the rest of your body, perhaps scrotal testicles evolved as a sort of ornamental display communicating the genetic quality of the male.

Oh, and this, on how a man’s cremasteric muscle works to keep his sperm at an optimal temperature by contracting and drawing the testicles up on a cold day and relaxing when it’s hot:

[That's] why it’s generally inadvisable for men to wear tight-fitting jeans or especially snug “tighty whities”–under these restrictive conditions the testicles are shoved up against the body and artificially warmed so that the cremasteric muscle cannot do its job properly. Another reason not to wear these things is that it’s no longer 1988.

In all seriousness, there’s nothing Discoblog values more than analysis of the silly… other than over-analysis of the silly. If you haven’t had your fill of scrotal hypotheses, check out the rest of Bering’s post.

Image: iStockphoto

World Famous Sex Blogger’s Day Job? Research Scientist.

Brett Israel — Tue, 17 Nov 2009 14:25:00 +0000

Belle de Jour, the best-selling author who penned books about her life as a call girl, revealed her true identity over the weekend. Her name is Brooke Magnanti.

Dr. Brooke Magnanti to be exact. It turns out she’s a cancer researcher who began turning tricks while in grad school.

Via the London Times:

Magnanti is a respected specialist in developmental neurotoxicology and cancer epidemiology in a hospital research group in Bristol. Six years ago, in the final stages of her PhD thesis, she ran out of money and turned to prostitution through a London escort agency, charging £300 an hour. Already an experienced science blogger, she began writing about her experiences in a web diary that was adapted into books and a television drama starring Billie Piper.

It’s not like she didn’t try to find honest work. She told the Times that at one point during her double life she had a job as a computer programmer, “but I kept up with my other work because it was so much more enjoyable.”

So what do you think readers? Is this a commentary on how poorly grad students, and scientists in general, are compensated?

More reactions over at The Great Beyond.

Image: flickr / keepwaddling1

Sea Section: Shark Bites Shark & 4 Babies Pop Out

Eliza Strickland — Thu, 12 Nov 2009 22:25:36 +0000

Some sharks have a nasty habit of taking bites out of each other, but in an aquarium in New Zealand one aggressive shark ended up doing its tank-mate a favor when it tore out a piece of the second shark’s belly. Visitors at Kelly Tarlton’s Underwater World watched in shock as four baby sharks popped out of the gaping wound. The visitors ran to notify the aquarium staff, who quickly removed the babies.

Via the New Zealand Herald:

[Aquarium staff member Fiona] Davies said the unusual delivery had probably saved the baby sharks’ lives.

Staff did not know the mother was pregnant and, had she given birth naturally, most likely at night, the babies would have been eaten by adult sharks and stingrays before staff could rescue them.

When the mom was removed from the communal tank to get her wound stitched up, vets found four more babies inside her. All are reportedly doing well, despite the spontaneous C-section.

Image: flickr / snickclunk

What Head (and Other) Lice Tell Us About Evolution

Sam Lowry — Mon, 09 Nov 2009 18:51:07 +0000

The second episode of NOVA’s big evolution special “Becoming Human” premieres tomorrow night at 8 PM ET/PT on PBS. Tuesday night’s show focuses on Homo erectus, the ancestor who became “basically us” almost 2 million years ago, developing the first human societies.

Much of what we know about Homo erectus comes from “Turkana Boy,” the famous skeleton found by the Leakey team in Kenya in the early 1980’s. An important part of what we know, though, comes from the genetic study of lice. And not just head lice.

Using “paleoartists,” digital filmmaking and the work done with Turkana Boy over the past two decades, the NOVA producers are able to paint a vivid portrait of Homo erectus’s role in key innovations – like using fire and developing social bonds – that make us human.

The real action in the documentary starts about halfway through, when scientists tackle the question of how Homo erectus was able to obtain the protein necessary to support brain growth. Of course, stone tools played a huge role in making sure that the humans “went home for dinner and weren’t the meal.”

Per NOVA, “most predators rely on strength or speed to kill their prey, and our ancestors had neither.” Instead, according to Harvard’s Dan Lieberman, Homo erectus relied on the combination of “endurance running and high activity in the middle of the day.” Unlike animal predators, early humans were mostly hairless, giving them the ability to sweat and keep cool while running and tracking their prey over long distances.

The evidence for Turkana Boy’s hairlessness comes in part from the study of louse DNA. Hair is “rarely present in the fossil record” so researchers have turned to the study of parasites associated with hair, i.e. head and pubic lice. It turns out that the human head louse is very different from the human pubic louse. On top of that the pubic louse is closely related to lice found on gorillas. Viewers are left to draw their own opinions about how humans contracted pubic lice from gorillas. When humans lost their hair, the lice were forced to navigate “the hairless geographic barrier” between the head and pubic regions.

By studying the genetic code of the two louse species, geneticists like Mark Stoneking of the Max Planck Institute can tell when the two species diverged from their common ancestor. Their research suggests that humans lost their thick coat of body hair almost three million years ago, paving the way for Turkana Boy to outrun and kill the meat he needed to feed his growing brain.

So You Think You Can Dance: Spider Edition

Brett Israel — Mon, 02 Nov 2009 17:06:19 +0000

If you thought going to the club was bad, imagine having to dance in front of potential mates for over an hour and a half, lest they will eat you. Male Australian redback spiders, members of the black widow family, pay the ultimate price if their mating dance doesn’t impress.

Here’s how it works, via Livescience.com:

Males, which are just 1 percent to 2 percent of a female’s body weight, dance about the web of a potential mate, plucking at the threads and sending out vibrations. Once the male redback has performed an adequate dance, the female will allow him to mount her and insert one of his two palps, or copulatory organs, into one of a pair of sperm storage organs. The male then somersaults to place its abdomen directly above his mate’s fangs. That’s perfect positioning for the female to begin devouring the male’s body.

To avoid being gobbled up by the female halfway through mating, males need to dance for 100 minutes, according to new research. But the dancing males better have a good internal clock. Females can’t determine the source of courtship, so if the dancer exceeds the optimal time, a slick male could sneak in a mate with the female while the dancer ends up alone on the web.

For a video of the life-or-death dance, click on over to the Discovery News.

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DISCOVER: Stalking Spiders

Image: Ken Jones

Woman Gets Pregnant…While Already Pregnant

Melissa Lafsky — Fri, 25 Sep 2009 15:00:35 +0000

A woman in Arkansas is pregnant with two babies at the same time…except they aren’t twins. ABC News reports:

Doctors successfully located Todd and Julia Grovenburg’s growing baby girl Jillian, but then discovered another smaller baby — what could be Jillian’s younger brother — growing beside her.

The Grovenburgs may have conceived their son Hudson a full two-and-a-half weeks after Jillian, according to statements given to KFSM-TV in Ft. Smith-Fayetteville, Ark.

There’s even a name for what happened: superfetation, or conceiving while pregnant. Unsurprisingly, it’s extraordinarily rare—one doctor said she could only track down 10 reported cases.

Granted, there’s a big problem—what happens to the younger baby when the older fetus is born?

“It [the second conception] can happen up to 24 days later than the first conception, and then you’re putting the second baby at risk for lung development problems,” said [OB-GYN Karen Boyle].

However, in the Grovenburg’s case, Boyle said the difference of two weeks would not put the younger baby at much of a risk for health problems.

Talk about dodging a bullet—though birthdays in the Grovenburg household should be interesting.

Image: iStockphoto

New Shark Has “Retractable Sex Appendage” on Its Forehead

Brett Israel — Wed, 23 Sep 2009 16:40:30 +0000

“Really! I was born that way! I swear!” A new species of shark was discovered in California recently, called the Eastern Pacific black ghostshark. It’s part of a group known as big black chimeras, and members of the species have actually been laying around pickled in museums since the 1960s—but only recently have scientists realized that the black ghostsharks were in fact a separate species.

One possibility is that past scientists were too distracted by the sharks’, er, highly unusual feature that they lumped them in with the other chimeras.

Douglass Long, author of the study (PDF) detailing the new species, described the shark to National Geographic News:

Male chimeras…have retractable sexual appendages sprouting from their foreheads. These organs, which resemble a spiked club at the end of a stalk, may be used to stimulate a female or to pull her closer—though these are still assumptions, Long said.

So basically these guys have a mace swinging from their forehead that they use to club female sharks. Talk about a remarkable trick of animal mating.

Image: MBARI

Is It “Science” to Show Cadavers Having Sex?

Boonsri Dickinson — Mon, 14 Sep 2009 18:53:18 +0000

Yes, sex sells. But should it sell science? Anatomist Gunther von Hagens plans on opening a new kind of Body Exhibit, one that is akin to a sex show of dead corpses. The Swiss have already granted him the OK to set up the show in their country, as part of the Body Worlds exhibit. He’s tried to put it on before in Berlin, with a male and female corpse having sex, and met with protests. In response, he claimed that the two subjects had signed consent forms prior to their death, and agreed to have their bodies displayed in a sexual way.

Now, Reuters reports he’s ready for a full on show:

Von Hagens and his wife Angelina Whalley show corpses prepared using a technique invented by von Hagens called “plastination,” that removes water from specimens and preserves them with silicon rubber or epoxy resin.

“It’s not my intention to show certain sexual poses. My goal is really to show the anatomy and the function,” Body Worlds creative director Whalley told Reuters in an interview, adding the sex exhibition may open next year.

The regular Body World exhibit has racked up 27 million visitors, but constantly is called controversial for their use of corpses and dissection of skin and internal body parts. And while teaching about anatomy is a noble goal, is there really any educational purpose to this sex show? Or is von Hagens just very good at getting free press?

Related Content:
DISCOVER: Gross Anatomy

Image: flickr/ dustinkeirstead

Can Pheromone Body Wash Make You More Desirable?

Allison Bond — Thu, 30 Jul 2009 18:50:39 +0000

If you’re hoping to appear more attractive to potential mates, the solution may be simple: Just shower with some pheromone-laden body wash, or dab on some lip gloss containing these so-called “attraction chemicals.”

At least, that’s what the makers of an increasing number of pheromone-based products want you to believe. Body washes, cosmetics, perfumes, and more all boast of their pheromone contents. There’s just one problem: There is no scientific evidence that people produce or respond to pheromones at all, or that dabbing them on will make you more attractive to potential mates.

This dearth of scientific evidence didn’t dissuade Dial, however. The soap-maker recently released a “pheromone-infused” body wash, then held a speed-dating “experiment” in which nine blindfolded women had to choose between nine men (some had used the wash, some hadn’t) they would go out with in order to “prove” the wash worked.

The way someone smells can obviously affect how much you want to be around them; in fact, scent has even been shown to influence attraction. But it’s never been proven that humans can “smell” pheromones, and their purported effects are far from scientific fact. According to the New York Times:

“There has been a lot of misconception about what human pheromones do,” said Dr. Charles Wysocki, a behavioral neuroscientist at Monell Chemical Senses Center in Philadelphia and an author of “Human Pheromones: What’s Purported, What’s Supported,” a recently published report commissioned by the Sense of Smell Institute, a branch of the Fragrance Foundation. “We want to raise a flag and say, where’s the evidence? How human pheromones work is still totally questionable.”

At least we can take consolation in the noble cause the product developers have in mind:

“We don’t claim using our product you’re going to hit a home run,” said Ryan Gaspar, a [Dial] brand manager. “We say, ‘We’ll get you to first base.’”

Image: flickr / lissalou66

Modern Love: P.A. Woman to “Marry” Rollercoaster

Allison Bond — Wed, 29 Jul 2009 18:43:45 +0000

Plenty of people love roller coasters—but few as much as Amy Wolfe, a 33-year-old Pennsylvania woman who plans to marry one.

Wolfe is the latest in a series of people who have married inanimate objects, from the Berlin Wall to the Eiffel Tower. This type of sexual behavior has a name: objectum sexual, meaning a person becomes attracted to, and even falls in love with, non-human (or even -animate) objects.

According to a perhaps-too-detailed report by The Metro U.K.:

[The woman] enjoys a “satisfying” sexual relationship with a fairground ride – a “magic carpet” themed ride named 1001 Nachts – and now plans to marry it. The 33-year-old rides the machine 300 times a year and uses pictures of it to satisfy herself at home.

Because she lives about 80 miles from the amusement park, the relationship has been long-distance. But even if Wolfe relocates to be closer to “her” ride, we’re willing to bet this marriage will have, er, more than its fair share of ups and downs.

Image: flickr / Thomas Euler