On the Evolution of Oral Sex: It's Actually Good News!

If you thought that fellatio was an entirely human thing, then think again! Naughty, naughty scientists have long been studying how the primates do it. There have been some documented cases of bonobos Pan paniscus performing it, but these little animals are well known to be really kinky, not to say very promiscuous. In terms of evolution, primates are very closely related to humans, so scientists expect them to be a heck lot more likely to be involved in non-vanilla sex than other species.



The short-nosed fruit bats Cynopterus sphinx are not the type of guys that you expect to be exactly...err...adventurous. But one day, a couple of scientists woke up and decided to put cameras in their rooms, without their knowledge. Call them voyeurs or call them explorers, the study was approved by a national panel on animal care.

The authors studied 20 couples and looked at how fellatio affected the length of sex. To be precise, as scientists often are, they defined length of copulation as "when the penis entered the vagina until when it withdrew completely." The males would normally approach from the back of the females who would then reach down and provide some lubrication to their partners, still behind. The males never seemed to object to it! Very rarely did some of the females run away, but they were quickly chased by the males and within 8 to 25 seconds, the sex continued.

The result:

Females were having sex for longer time when they performed fellatio on their partners. More specifically, for every 1 second of fellatio, the couples gained 8 seconds of copulation.

And yes, the scientists do think that there are evolutionary benefits to fellatio! What benefits you might ask? Well, at least for these bats, they hypothesize that the adaptations might provide evolutionary incentives ranging from the prolongation of copulation to the ability of females to taste whether they have made the right mate choice. Who knew?

But the humble authors would agree that we shouldn't stop looking at these types of behaviors just yet... because we do not know exactly, for sure, why fellatio happens. And that topic totally deserves some more exploration.



References:

Tan M, Jones G, Zhu G, Ye J, Hong T, et al. (2009) Fellatio by Fruit Bats Prolongs Copulation Time. PLoS ONE 4(10): e7595. doi:10.1371/journal.pone.0007595

De Waal FBM (1995) Bonobo sex and society: the behavior of a close relative challenges assumptions about male supremacy in human evolution. Sci Am 272: 82–88.

Palagi E, Paoli T, Tarli SB (2004) Reconciliation and consolation in captive bonobos (Pan paniscus). Am J Primatol 62: 15–30.

Schürmann C (1982) Mating behaviour of wild orangutans. In: Boer LEM, editor. The orangutan, its biology and conservation. The Hague: Junk. pp. 269–284.

Koyama N (1988) Mating behavior of ring-tailed lemurs (Lemur catta) at Berenty, Madagascar. Primates 29: 163–175.

March Post!

Coming soon!!

Animalistic Valentine's Day

(these are not yet edited)

Last time I checked, humans can learn a whole lot of naughtiness from our animal neighbors.


1. Our parents already told us that sex is dangerous, and if you don't believe them, check out octopuses. The males actually have it so -ahem- rough, that their penises brake off after sex. No worries though, they grow right back the following season.

2. Who said that oral sex can't get you pregnant? The female cichlid fish carries her eggs in her mouth and these eggs get fertilized right there by a male.

3. Make war, not love. Because hermaphroditic flatworms have both sexes, two worms would pull their genitalia, use it as a sword and start fighting each other. The winner gets to be the male.

4. Making babies is all about the belly. Ask a bedbug. A male just jabs a female bedbug in the belly when he wants to mate.

5. The biggest orgies are from the red side garter snakes. One female -- hundreds of males.

6. Size does matter, a lot. A male slug has his penis so big that he must find a mate of suitable size. Otherwise, he risks having his penis bitten off.

8. Male gold-diggers. The male angler fish latches unto the female, then eats off her food until she is ready to fertilize.

9. Not-so-romantic kisses. Midges often look like they are kissing, but it's just a female sucking out a male's bodily fluids.

10. Anal what? When a male hippo is hot for a female, he uses his tail and sprays her with feces. The lady hippos find it irresistible.



11. He really loves her to death. The male brown antechinus will have sex with one female for up to 12 hours. Then he might die. Or resumes sex with another female. The males only survive one mating season.

12. Females prefer bisexual earwigs. And by that we mean earwigs who have two penises. According to scientists, they have more sex. Who would have thought?

13. Girls just wanna have fun, at least for the whiptail lizards. The males have been wiped out because of a genetic phenomenon. The females are parthogenetic unisexual copulators. The females reproduce exact copies of themselves.

14. Silky bondage. A male lynx spider traps the female of his love in a web of silk. He then distracts her with a romantic dinner of insect on the web, while he proceeds to sex.

15. Eating and heads. The female praying mantis literally rips the head of her mate after sex. She can also eat his head during sex.

16. Promiscuous girl... Giraffes have sex with as many partners as possible, and they do it year round. The male usually first tastes the female's urine, if it tastes good, it's on.

17. If I were a boy... When the dominant male of the cleaner fishes dies, a female becomes the new male (protogynous hermaphrodite). The dominant male selects a female, dances with her, releases sperm, while other the males of the audience do the same.

18. The male porcupine sprays their mates with a stream of urine. I don't think that they named that a golden shower.

19. A dolphin handshake will make you blush. Dolphins actually have a retractable penis on their flippers. Not to mention a very high sex drive. The males mate VERY often and reach orgasm in 12 seconds.

20. And the most romantic of all... Biologist have given up making list of how horseshoe crabs have sex. They try a lot of new things, often on the beach, and under the moonlight :)


ADVICE OF THE MONTH!

If you still have Valentine Day's flowers that you do not want to die, you might be better off getting some vodka. Drinking the vodka won't help much, but if you put a bit in the water that holds your flower, you roses might live longer.


Did you know... that a survey conducted by Durex condom indicated that Eastern Europeans have the most sex. It gets cold in Russia, you know. (Discovery.com)


(None of the above information comes from my original research. I am merely presenting known information for "educational" purposes. All of this stuff can be found online, a book, or whatever...)

Why are some girls naturally guys?!

Today's blog:

(This is my very first attempt doing this. Let me know if there is too much science, or too little. Too much sex, or too little. Let me know what is not clear, etc. I need more than one opinion to make this more useful. With your help, this should become really juicy and the best thing since chocolate :) )


So, anatomy is only part of what defines a person as male or female. At times, we would rather not think about anything that can happen in between (no puns intended). Well, who wants to be called an "86% guy" anyway?


Consider this... Jane Doe has a well-defined female sexual organ and secondary female sexual characteristics. Jane is an amazing athlete who never menstruated. At the doctor's office, Jane checks the box next to "Female". Next to the "Single" box, which she checked, she writes happily that she just got engaged. She is worried about getting married because her aunt can never have children. What would you vote? Guy or girl? Most people at this point might agree that Jane is a girl.


People have 23 pairs of little packages of DNA inside their cells called chromosomes. The doctor decides to look at Jane's. The chromosomes numbered 23 usually have the shape of "XX" for females and "XY" for males. Jane's chromosomes look like "XY". This is the beginning of the confusion.


See, actually, when babies are still in the womb, their developing genitalia actually look neutral. Within the first seven weeks, you can't actually tell from looking. But if the baby has a Y chromosome, something in that Y chromosomes start signaling the fetus to start destroying cells that would otherwise become the uterus. That something signals the body to start making testes out of the "bipotential" fetal gonads (ei, the little parts of the baby's body that can either become an egg- or sperm-containing glands).


The part of the Y chromosome that actually does the work is a gene called the SRY gene coding for a "testis-determining factor". What that means is that if a person who has a Y chromosome does not have that SRY gene, that person won't have testes and won't look like a male! But actually, for Jane, not only does she have a Y chromosome, but her SRY gene is fully functional. The presence of an SRY gene is one of the criteria used to determine "maleness". Then, what sex is Jane?

There must be other things besides SRY that are involved in the formation of genitals. Obviously, right? Jane has a vagina. Jane's hormone levels look more like those of males than those of females. But hormones are signals and need receptors to tell a person's body what to do. Jane is missing some of the testosterone receptors that are needed to make her develop more male characteristics. So her body makes signals like males and does not respond totally like males.


Now the million dollar questions:

• Is Jane obligated to tell her fiancee that she has a Y chromosome?
  
  
• Should Jane be called male, female, or neither?
  
  
• Should Jane, as great as she is at sports, be allowed to compete in the Olympic against typical women? What do you think?
  
  
• Should an organization be allowed to require someone to get his or her chromosomes checked?
  
  
• Say that modern science is able to help Jane conceive a baby, with a woman, should that technology be put into use?
  

(Jane has complete androgen insensitivity syndrome or CAIS. She is a form of male hermaphrodite, but not a true hermaphrodite because she does not have two pronounced sexes. In real life, 1 out of 20 000 people have this condition. That's actually a lot of people. Imagine that NYC alone has millions of people. The medical community agrees that people with that condition are female. CAIS patients are eligible to compete as women in athletic events.)


Did you know... That pigs can orgasm for 30 minutes straight? Now that's some happy pigs!

Welcome to Sex with Science!!

Dear Reader,

I am very excited to present to you Sex with Science! This is a public service blog. I will try to write about scientific aspects of sex topics that you would never dare to ask your mom and dad about. This blog should certainly be work safe. I look forward to hear your questions! Let's talk nerdy :)

Cheers,

Sex with Science