Grapes, part three

[urbpan]

One of the things about taking care of a variety of different animals for a living, is that you become intimately acquainted with the smells they leave behind.  This is neither a good thing or a bad thing, it simply is.  The negative side is that most of these smells are bad smells from waste products; the positive side is that it helps you understand the animals better, and gives you another tool in determining the animals' health and well-being.

I took care of red foxes at Drumlin Farm for about seven years.  Their cage had a strong skunk-like odor that visitors were sure to mention if someone was there to hear it.  We put up signs explaining that our skunk was descented and that they were smelling the fox cage.  The smell comes from sulfur compounds, possibly from the fox' anal gland, and helps them mark their territory.  It's normally pretty faint, and you aren't likely to smell it in the wild, but in a soil-lined concrete cage, it gets pretty funky.  But that's not the smell I want to discuss.

There's another smell, beneath the powerful skunk smell, which I especially noticed when the foxes would urinate into their food bowl.  (This wasn't unusual--wild foxes sometimes urinate on their food caches.)  There was something so familiar, and dare I say it, pleasant about this other smell.  I realized that it was the smell of Concord grapes--above and beyond the normal smell of grapes, Concord grapes have a musky powerful essence that distinguishes them from other grapes.

I thought I might be crazy to think this, or that perhaps some component of the grapes we fed the foxes (each fox got three grapes per day) came out into their urine.  Then I encountered a reference to "fox grapes" and did a little digging.



Concord grapes, as it turns out, are one of several cultivated varieties of Vitis labrusca, the fox grape.  Concord grapes are so well known that their common name has eclipsed the name "fox grape" in recent years.  But for a long time the name fox grape was used to describe this fruit-bearing vine native to eastern North America.  It appears that the name came from the "foxy" odor and flavor of these grapes.   Early colonists would have been much more in touch with the essence of fox, since killing them was a sport and a duty (protecting the chickens and all).  Fox urine would have been part of the olfactory palette of life, along with horse manure, freshly chopped firewood (different kinds distinguishable by odor), and smoked cod.   The modifier "foxy" when referring to grape flavor, is still used by wine enthusiasts.  That essence that I attributed to concord grapes is one of the many flavors that can be found in wine. 

Clever chemists have delved into the secrets of the flavors of grapes, and found a compound called Methyl Anthranilate, both in the skins of grapes and in the musk glands of foxes.*  This chemical can be artificially synthesized, and has been, by the ton.  It is used as grape flavoring in candy, soda, popsicles, you name it, basically any processed food that is purple gets its purple flavor from Methyl Anthranilate.  So what?  Chemists synthesize lots of flavors (like the chemical found in the Western Conifer Seed Bug which is the same chemical used to flavor candy like sour apples).

Then in 1994, someone discovered a new use for Methyl Anthranilate.  Someone (I don't know who, or how, or what the hell they thought they were doing) found that if you spray this stuff on grass, Canada geese won't eat it.  There are a great many people out there willing to pay a great amount of money to keep Canada geese off of grass, so MA (as it is known in the pest control biz) became a commercially produced goose deterrent.  The main problem with it is that if it rains, the stuff washes away and needs to be reapplied.  I haven't read if runoff has produced any grape flavored ponds.

I learned about MA a few years ago when I took a course on "Living with Canada Geese" sponsored by the MSPCA and run by an outfit called GeesePeace.  The people running that class explained that MA affects birds in a way that's analogous to the way capsaicin (the active ingredient in hot peppers) affects mammals.  In researching the relationship between these two chemicals I quickly found myself over my head.  "Repellency in birds is enhanced by electron richness of the phenyl ring and basicity and reduced by acidic functionalities.  The reverse is true for mammals."  (Chemical Ecology of vertebrates By Dietland Müller-Schwarze, p. 397).   However that paragraph did include the information that MA "given in water also reduced feeding in mice."  Mice don't like grape juice?  Mice have adapted to avoid fox odor (mice and voles are the primary prey of foxes)?  Lots of room for study, for someone.

Lately there has been more movement on the pest control front, as regards to the use of MA.  I learned (via gmail text ads) of a product called Bird Buffer.  According to the maker of this product, they have found a way to adapt machines used to make fog for stage shows, to blow "nano-particles" of MA over the area you wish to protect from birds.  The idea is to keep big flocks of birds (they don't specify what kind of birds, but presumably pigeons--there are more complicated instructions for dealing with "small birds," sparrows and probably starlings), from roosting in open warehouses and other places.  The machine is meant to be used at dawn and dusk when most of the birds are flying in and out.  The particles of MA are so small that the product is supposedly only effective on flying birds, which are "breathing faster." 
This causes a minor irritation which makes the birds choose a different roost.  Also your warehouse then smells like grape Kool-aid all day, which beats the smell of bird shit.

This isn't an endorsement--I certainly can't use the thing at the zoo and tear-gas all my ducks just to keep the sparrows out.  But it is interesting to me.  The fox urine thing nagged at me about five years ago, and it wasn't until I read about the Bird Buffer that I filled in the blanks in between.  It makes me want to have a glass of wine to celebrate.

* I found this information from one source only: a blog entry from April 2002 called "How Foxy is She?" by Larry Moore on a site called RE: Whatever.  It connected a lot of dots for me, but I can't verify some of the stuff in there, including the presence of MA in fox musk.

Here's a cute site on MA done by a chemistry student.  I found it helpful.

Comments

[takarosa.livejournal.com]

That was fascinating! Thank you for sharing this information. We have a fox we occasionally see in the fields here and I believe it's my favorite of the local wild life.

A side note. I have two pet rats. When they are clean, they also have a very distinctive, but pleasant mild scent. A friend named it and I found it spot on. They smell like grape soda. It's so unusually sweet for an animal smell.

[urbpan.livejournal.com]

It's interesting. I didn't notice the rat smell, but woodchucks smell a bit like chinese food or chicken soup. The zoo hospital has one ward with a Mandrill funk that just won't go away.

[takarosa.livejournal.com]

Both my rats are female, and that may be why the smell is more obvious than the musky males. I notice it when she's cuddling under my chin (she fancies herself a cleavage critter!)

My Amazon is mostly scentless, just demanding. Smells fascinate me.

I really love the term "Mandrill Funk" I think it'd make a spectacular band name.

[harrietbrown.livejournal.com]

My Mom planted a Concord grape arbor in the backyard and it gave off a wonderful earthy aroma, especially in fall. She used the grapes for making jam, jelly, and juice. No wine, alas. Norwegians are not exactly known for their wine-making abilities. I didn't realize the fox and the grape were so closely intertwined. Thanks for an interesting treatise!

[urbpan.livejournal.com]

You're welcome! It was stuck in my head and I had to get it out. It's good when I get obsessed with something that I can write out.

[morgi.livejournal.com]

So peeing on one's food cache is sort of the fox equivalent of "I licked it so it's mine?"

[urbpan.livejournal.com]

Yep. A lot of carnivores do that, including legendarily the wolverine, ruining traps and cabins in the process.

[cottonmanifesto.livejournal.com]

i am seriously not comprehending the link between grapes and fox stench.

[brush-rat.livejournal.com]

Pretty fascinating. So foxes actually eat graps. I always assumed that was poetic license in Aesop.

[urbpan.livejournal.com]

Foxes eat a variety of non-animal foods (reportedly) including fruits and corn and such. While I was at Drumlin we discontinued feeding grapes to the foxes since grapes are known to contribute to kidney failure in dogs. We gave them small pieces of apple, and sometimes pieces of corn on the cob.

[urb-banal.livejournal.com]

cool stuff

[agelena.livejournal.com]

Fascinating. Anything about foxes is interesting, and to tie them to grapes is a wonderful mad leap. I've always considered foxes to be the most feline of the canines: something about the way they move says "cat" to me.

[miz-geek.livejournal.com]

That was really interesting. Thanks for sharing it.

[propaddict.livejournal.com]

I nominate this entry for post of the year. It was like Bill Nye meets Steve Irwin and they do an Animal Planet special narrated by David Attenborough.

Yeah, it was THAT good.

Or, I'm just THAT much of a nerd.

[http://users.livejournal.com/_bazilisk_/]

Effing FASCINATING. Thank you. I love the trail this chemical can lead down.

Stupid idea: How about golf courses and suburban hellsuburbs stop using sprays made from the same chemical as found in fox pee and grapes to keep geese away, and instead just release tons of foxes, with lots of water sources, maybe even coffee (a well-known diuretic?) Tons cuter than sprays. It would keep the annoying bird-eating domestic cats away. And people annoying enough to be afraid of things like foxes.

[droserary.livejournal.com]

Fascinating!

This is a perfect post for cross-posting at wtf_science, don't you think? The poor community needs some action.

[wirrrn.livejournal.com]

I'm going to name my band Goose Deterrent *g*.

We could actually use some *fox* deterrent here Down Under. They're second only to feral cats in terms of the Native Fauna destruction...

[gemfyre.livejournal.com]

Hey, do you work with bears at all? One thing I noticed during my work experience at Perth Zoo was the intriguing poo of the Syrian Brown Bears. It seemed that they pooed out different foods at different times/places. Here was the fruit they ate, over the some digested meat, and here clearly is the remains of the cake left in the staff-room that one of the keepers gave the bear a bit of. It was rather fascinating.

[urbpan.livejournal.com]

When we had black bears in quarantine, I don't remember their droppings being like that, but their diet was pretty simple and mostly pelleted. I did notice that they smelled like dogs, though.

[obie119.livejournal.com]

This post is AWESOME - thanks!

And - I love the Drumlin foxes! The Silver fox is particularly spectacular, though I like the red one better. How cool that you took care of them.

I was sad to hear that the Woodchuck died though :(

[weofodthignen]

This was interesting, but very alien. I have hardly any sense of smell. If prompted by someone making loud noises of revulsion, I can occasionally smell licorice in the vicinity of a skunk. Otherwise I don't notice anything unusual.

M

Another odd tangent...

[(Anonymous)]

Great article! I came to the same guess about the mutual chemical component, but from a very different perspective. I actually got here by typing "methyl anthranilate fox" into Google, just to see if it would bring anything up. I'm a bartender (with botanical training that I abandoned due to pollen and mold allergies). I first became aware of methyl anthranilate several years ago when I found that adding a little orange blossom water (which contains the chemical) to any red or purple berry gave a distinct grapey flavor. A little research provided the link, as well as vague mentions of "foxiness" in relation to the grapes that contain it.
Much later, however, when trying to figure out what made a particularly disagreeable cashew wine so gaggingly awful, I couldn't place the animalic scent and filed it away in the back of my mind. The epiphany came during a tasting of various meads--those made with nut-tree or wildflower honey tended to be pleasantly rich and earthy, while the orange-blossom-honey meads (though lighter and more evanescent) tended to have that same rabbit-cage aroma I remembered from the cashew wine. Could it be the methyl anthranilate? Does the same thing make the dog runs in my neighborhood stink to high heaven, or perhaps a close chemical relative? After a walk in the august evening heat today, with the dogs particularly ripe, it all came together and I ended up (with Google's help) here. Thank you for the article, and the Hemsted lead! Aroma chemistry is a fascinating thing.