Oh, Hello! Why Yes, That’s My Crotch

Part I: Sniffing researched
By Julie Hecht, December 2011, Updated February 2015

The holiday season is in full swing. But before you dive into Aunt Bessie’s famous cookies, you might have to get past a few pinched cheeks and possibly some bad breath.

You know what I'm talking about—from handshakes and hand-kisses, to “man hugs” and double kisses, between now and New Year’s, we humans enter hardcore greeting mode. 

Accompanying the acceptable greeting rituals noted above, we also engage in the more discrete variety: the up-and-down glance we get from our sister as we enter the party (I hope she didn’t notice that I’m wearing her bracelet!); the feeling that someone tried to get a look at your shoes without you noticing (of course you noticed). This is what we do. We check each other out.


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What about dogs? Come holiday season, any dog who’s a fan of people will most certainly put on his greeting hat. And when dogs are greeting people or checking people out, they tend to go for the crotch. Or do they?  

The sniffing investigation
Back in 1991, Filiatre et al. published a study: Behavioural variability of olfactory exploration of the pet dog in relation to human adults.* In English, this translates to: Do dogs differ in how they sniff their owners vs. how they sniff strangers?

The researchers created a study with two parts. In part one, they observed pet dogs sniffing their owners. In part two, pet dogs sniffed an unknown person. The researchers then studied which human body parts received the most attention from the dogs and their sniffers.

The first thing you are probably wondering: How exactly were people sniffed? (Not something you ask every day.) For the sniffing simulation, the human subjects entered a test room where they lay motionless on the floor with their eyes closed. Once on the floor, the dog entered the room and was observed for five minutes.

To collect the sniffing data, the human body was divided into 10 regions (see below). Researchers could then easily observe where dogs were directing their sniffing. I might add, this mock human has abnormally small feet and nice underwear.

The sniffing report
On the whole, dogs spent more time sniffing their owners than the strangers.

But there’s more!

Dogs differed in how they sniffed. When it came to sniffing their owners, dogs showed particular interest in the thorax and arms. On the other hand, in the presence of a stranger, dogs focused more on the ano-genital area and thighs. Whether you are more familiar with the terms “privates,” “bits and pieces,” “caboose,” “backdoor,” “flower pot” or “Rocky Mountain Freeway,” no matter how you slice it, dogs were more into sniffing the crotch and thighs of strangers compared to the crotch and thighs of their owners.

For you visual learners, below is a picture detailing the movement of the dog’s muzzle over the body. Top image: sniffing a known person; bottom image: sniffing a stranger. Check out that crotch attention! 

So why might your dog get all up in Aunt Bessie’s crotch during the holidays? Simply put, he hasn’t seen her in a year! Maybe if you invited her over for tea more often …

Tune in next time for Part 2: Why is a stranger’s crotch so much more interesting than mine?

Julie Hecht, MSc, is a PhD candidate studying animal behavior at the Graduate Center, CUNY, and author of the Dog Spies blog at Scientific American. She would really like to meet your dog. Follow on Facebook and Twitter.