What are armpits for? | Greg Foot | Ask Head Squeeze
1,499This week on #AskHeadSqueeze Thursdays, Greg Foot answers a question from Kevin Sheppard on our Head Squeezers Google+ community. What are armpits for, and why are they hairy? Interested in how the smell of your sweat could help you score? Watch away.....
00:43 Why do we have hairy pits?
There's a few theories here. One idea is that your hairy armpits stop your lymph nodes from overheating.
Foot Note 1: A moat around castle walls: The role of axillary and facial hair in lymph node protection from mutagenic factors. KomarovaS. Medical Hypotheses, Vol67, Issue 4 (2006), Pg 698-701
http://www.ncbi.nlm.nih.gov/pubmed/16690220
Another is that the hairs actually reduce friction when you walk. But the third theory is the one Greg's keen to talk about -- that hairy armpits are all about sweating and releasing sex pheromones.
01.08: Where does the sweaty smell come from?
Before Greg goes Sherlock, he has to explain where your smell comes from.
Foot Note 2: Microbiological and biochemical origins of human axillary odour.
James AG, Austin CG, Cox DS, Taylor D, Calvert R. FEMS Microbiol Ecol. 2013 Mar;83(3): 527-40.
http://www.ncbi.nlm.nih.gov/pubmed/23278215
02:01 What does your sweat say about you?
Sometimes your smell can say a whole lot about you, your status, your gender, and your reproductive state - especially if you are a Hyena.
Foot Note 3: Animal behaviour meets microbial ecology
Archie E, Theis K. Animal Behaviour, Vol 82, Issue 3, 2011, Pg 425--436
http://www.sciencedirect.com/science/article/pii/S0003347211002399
Even in humans, the underarm smell could have a role in attracting a partner.
Foot Note 4: MHC-correlated mate choice in humans: a review.
Havlicek J, Roberts SC. Psychoneuroendocrinology. 2009 May;34(4):497-512.
http://www.sciencedirect.com/science/article/pii/S0306453008002667
03:00 What is the Major Histocompatibility Complex?
The MHC is a bunch of genes that are important and are linked to not only your smell but your immune system. Experiments have shown that some women found a man's smell more attractive if his MHC was different from their own. It's thought that this is because their children will have a stronger immune system if they get two different sets of these genes.
Foot Note 5: MHC-Dependent Mate Preferences in Humans
Wedekind C, Seebeck T, Bettens F, and Paepke A. Proc. R. Soc. Lond. B 22 June 1995 vol. 260 no. 1359 245-249
http://rspb.royalsocietypublishing.org/content/260/1359/245.abstract
04:01 How are steroids linked to your smell?
Androstadienone is a by product of testosterone, and researchers have found that women exposed to it at a speed dating event were more likely to rate men as attractive.
Footnote 6: Evidence that androstadienone, a putative human chemosignal, modulates women's attributions of men's attractiveness.
Saxton T, Lyndon A, Little A, Roberts C. Hormones and behavior 2008; 54(5): 597-601
http://www.ncbi.nlm.nih.gov/pubmed/18601928
04:44 Who has the smelliest armpits?
This is the battle of the sexes -- who is smellier, men or women? Well, the research was done by the Monell Chemical Senses Center, and they found...it was men. Sorry guys. And, bonus fact , women apparently prefer the "odor signatures" from men who are on a non-meat diet.
Foot Note 7: The effect of meat consumption on body odor attractiveness.
Havlicek J, Lenochova P. Chem Senses. 2006 Oct;31(8):747-52. Epub 2006 Aug 4.
http://www.ncbi.nlm.nih.gov/pubmed/16891352
Do you smell? James May can't help, but he can tell you how deodorant works. https://www.youtube.com/watch?v=8LabJoi9w4s
And if you're still feeling hopped up on animal magnetism, Greg Foot answers more mammalian questions in Can Animals Taste. https://www.youtube.com/watch?v=gqKdNfJzC-g
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