Posts tagged ‘scent’

Do I smell a rat (er, mouse) in TSA’s future?

I hope so.

Israel21C recently reported on new technology that might someday replace invasive pat-downs and body scans TSA treats us to at the airport:

Israeli startup Bioexplorers has developed a new and unique way to sniff out terrorists – literally. After years of research, company CEO Eran Lumbroso tells ISRAEL21c, Bioexplorers has hit upon a foolproof, non-invasive and easy method to detect contraband in purses, luggage and even cargo – using mice.

Like dogs, mice have an excellent sense of smell and they’re relatively easy to train. As much as it pains to me admit it, mice offer some advantages. Their small size means they’re cheaper and easier to keep than dogs are, and because they don’t need human handlers, mice also won’t be sensitive to their prejudices.

The proposed system will combine low tech mice with high-tech training and screening equipment. The target to be screened will move through a passageway equipped with fans that extract the air surrounding the target and deliver it to chambers containing several mice. Each mouse is trained to respond to a single odor. When a mouse detects the target odor it moves into a second chamber and sets off an alarm.

Bioexplorers’ system is interesting because not only could it allow for less invasive screening than existing measures but, as an improvement over existing canine detection methods, it could also give screeners the ability to determine exactly which odorants have been detected.

Initial tests are promising.

[Bioexplorers] has conducted several tests at sites in Israel to ensure that the sensors work in real situations, including at Tel Aviv’s Azrieli Mall. More than 1,000 people passed through a Bioexplorers sensor – some having been given “suspicious” objects and substances to hold – and the mice made the right call every time, says Lumbroso.

The company says they can train mice in just two weeks using a patented Skinnerian computer program. Mice will be expected to work four hour shifts with eight hour rest periods and each mouse’s career is anticipated to last about two years.

It’s an interesting idea and there may be additional uses for the tiny detectors. Bioexplorers’ representatives say they’re also working on systems designed for medical use.

They may be able to detect drugs and explosives at minute concentrations, but the mouse’s nose may be too refined for use in the wine industry. The io9 forums report that researchers at Japan’s Hiroshima University conducted an experiment in 2008 to see if they could teach mice to tell different kinds of wine apart. The experiment was successful so the group decided to take the idea a step further and see if they could teach mice to tell different brands of red wine apart.

The results were interesting.

Only two of the ten mice tested displayed the ability to consistently tell the red wines apart. Six others performed on a what appeared to be a purely random basis.

But the final pair of connoisseur mice could not be persuaded to respond the target wine. These mice were consistently drawn to a specific non-reward wine indicating that they preferred the smell of this wine to the food rewards offered by the alternate choice.

I’m not terribly surprised to hear that well-fed laboratory mice will sometimes prefer an alluring scent over certain food rewards. Smell plays a huge part in the social and intellectual life of a mouse. A good smell, or an interesting one, may provide the kind of intellectual stimulation that could be more lacking in a laboratory mouse’s life than food is.

And while mice may replace dogs in situations where a static location like an airport or freight terminal needs to be screened for a wide array of compounds, I suspect that dogs will continue to be the detector of choice in field situations for some time to come.

March 4, 2011 at 9:33 pm 7 comments

The dogs will need their own teevee

Because I don’t think we’re going to want to ‘watch’ the same things…

The UK Times reports that scientists at Japan’s Keio University are working on Smell-o-Vision technology:

The Japanese team adapted a Canon printer to squirt four “ingredient” scents and managed to get hints of mint, grapefruit, cinnamon, lavender, apple and vanilla, for a fraction of a second.

Something similar was developed in the US in the ’60s, with scents released from sachets hidden in the seats to make cinema audiences more engaged with the entertainment.

However, the smells took too long to clear the auditorium and they were scrapped.

I’m not sure that Smell-o-Vision’s going to be a big hit outside the dog world. Once advertisers get their grimy little paws on it, ads for cars, perfumes and fast food will hurl us into a continuous, headache-inducing state of olfactory overload.

And = I suspect that if real-life scents are pumped in crime dramas, film noir and Mike Rowe will lose a lot of their popularity!

Ready for movie night!

October 25, 2010 at 7:30 pm 4 comments

Detection work goes to the dogs

Dogs have helped men search for prey for thousands of years. Today their marvelously sensitive noses help us search for an astonishingly wide variety of things. In traditional search and detection methods dogs sniff the environment directly to search for prey, escaped felons, lost persons, explosives, contraband and rare plant and animal species. But now filter-search odor detection methods, also referred to as Remote Explosive Scent Tracing or REST, bring minefields to dogs instead of taking dogs to minefields.

In REST air samples are collected from minefields using vacuum pumps equipped with special filters. After the air samples pass through them the filters are protected so that they retain odorant molecules while they’re transported to a secure location for testing. Samples are collected under strict quality assurance and quality control protocols similar to those used in environmental investigation and monitoring programs.

While sample collection can be tedious and time-consuming, REST methods provide a relatively fast way to identify areas that are free of mines and they allow dogs and handlers to work away from the danger of mines. Detailed mine location methods then only need to be used in areas where evidence of mines has been detected.

This week CNN reported that similar methods are now being used to outwit rhino poachers in Africa. They report that:

… there are times when it is not practical to use dogs on the ground, as the tarmac at border posts gets too hot for them during the day, or if there could be a danger to the animal.

Now researchers at the South African company Mechem are adapting their Explosive and Drug Detection System to the fight against poachers.


Inspector T.C.Oosthuizen, of the South African Police Service, said: “When we work at Komatipoort for instance, the tarmac is so hot, it starts melting so you can’t get a dog to work from 12 o’clock in the afternoon.

“And the smugglers, they know about it, so then they know you can’t bring a dog to the border posts because the dog of course will burn.

“With this machine you take the samples, and give it to the dog in a controlled environment, an air-conditioned facility. It’s cool for the dog so the dog can work longer and more.”

Hot pavement may not be as dangerous as a minefield but if authorities can provide dogs and handlers with a safe and comfortable work environment they can work more hours and, we hope, identify more contraband.

Detailed information on REST and other mine detection methods was published in the Geneva International Centre for Humanitarian Demining’s (GICHD) Mine Detection Dogs: Training, Operations and Odour Detection in June of 2003. GICHD states that REST isn’t used to locate mines directly. It’s used to identify areas that don’t contain traces of explosives or other target scents so that detailed searches for mines don’t need to be conducted there. They’re sometimes referred to as “reduction methods” because they reduce the size of the area where dangerous and time-consuming mine locating work must be done.

Composite air samples are systematically collected across the minefield. Each sample contains the molecules that remain in a filter after the air passed through it when the sample was collected. The area over which each sample was collected is carefully recorded and this allows the perimeter of areas where scent was and was not detected to be identified.

REST methods allow a relatively small number of searchers and dogs to screen large areas quickly. GHCID reports that in mine work as much as 95% of target areas can be declared safe (or mine free) after REST screening. If similar results are obtained when searching for rhino horn, this means that detailed searches for horn only need to be conducted in a small percentage of vehicles and cargo passing through checkpoint areas.

REST methods are most efficient when the target is a rare and unusual odorant because if it is common or widespread all the sample filters would contain odorant and no areas can be eliminated. Rhino horn is rare and unusual, so the method applies well to these searches.

Because dogs don’t perform scent work perfectly, when clearing mine fields two or more dogs are used to check each composite sample. The samples are transported to a central location where they’re attached to stands that make it easy for the dogs to sniff them. The dogs are trained to sniff each filter and indicate a positive find by sitting or lying down next to filters where they smell traces of the target odorant. Once a dog has sniffed all of the filters individually, they’re moved to different locations in the stands and the same dog sniffs each one again. After each sample has been sniffed twice by the same dog, one or more additional dogs repeat the process with the same filters (or duplicate filters). If a filter is examined by each dog twice without any positive indications the area it was collected from is identified as being clear of the target odorant.

This kind of detailed duplicate analysis is probably not as important when searching for contraband instead of explosives. Even if each sample is checked twice by a single dog, authorities should be able to clear traffic through checkpoints much more quickly than they can with direct detection methods. And, as CNN notes, dogs can also search traffic at times and in places where it would not otherwise be safe for them to do so.

Rhinos are critically endangered and poaching is dramatically on the rise because of demand from Asian markets where horn goes for as much as $30,000 a pound. Just this week LiveScience reported that:

“Within South Africa’s national parks — not counting private land there, where poaching was rare — there were 10 rhinos poached in 2007,” said Matthew Lewis, senior program officer for African species conservation for the World Wildlife Fund. “Thus far in 2010 alone, more than 200 rhinos were poached within South Africa, with a lot of those poached outside national parks, so that’s a more than 2,000 percent increase in just three years’ time.”

Because the market has become so lucrative, organized groups of poachers now use high-tech equipment like helicopters, night-vision scopes, silencers and chemical immobilization to avoid detection and arrest.

I hope that REST helps authorities arrest more poachers in this deadly, and rapidly escalating, cat and mouse game before it’s too late…

September 23, 2010 at 6:28 pm Leave a comment

A breath of not-so-fresh air

That whiff of a buddy’s just-back-from-lunch garlic, onion, tomato, salami and beer breath may kill your appetite, but to a mouse it provides a powerful incentive to grab a pizza and beer for himself.

As reported last week at Science News:

For rodents, any food smell combined with breath odor sends an irresistible “eat this” message to the brain, reported Thursday.

Carbon disulfide, a metabolic byproduct found in the breath of many mammals, stimulates specialized cells in the mouse nose, scientists report in the journal Current Biology.

These cells send a signal to specialized structures within the mouse brain that links an incoming odor with food that’s safe to eat, researchers said.

Olfaction arises from the interaction of several astonishingly complex subsystems. And they do a lot more than just detect odors. While some receptor systems help animals detect and decode a wide range of chemosensory input others affect and regulate specific kinds of behavior.

GC-D cells are a set of neurons in the main olfactory epithelium that detect specific hormones and urinary stimuli. Although GC-D cells were first identified back in the 1980’s, there’s no evidence that they play a role in odor recognition. So why are they present in some mammalian noses?

According to Science News:

Special nasal cells, called GC-D cells, seem to respond to the CS2 in rodent breath, experiments by Munger and his colleagues reveal. A mouse that smells cinnamon on a buddy’s breath will choose cinnamon-scented food over any other flavor, the researchers found. And it doesn’t even have to be another mouse: Cotton balls laced with a food odor and CS2 did the trick. But mice without working GC-D cells lost the ability to interpret this chemical message and they didn’t copy their compatriots’ food choices, the team reports.

The new work provides a molecular explanation for how these rodents learn what’s OK to eat, says neuroscientist Emily Liman of the University of Southern California in Los Angeles. For people and other primates, food preferences are mostly learned visually (or compelled via threats of no dessert). But for nocturnal creatures such as rodents, visual cues are limited. So it makes sense that there’s a scent signal, Liman says.

This safe-to-eat signal is so powerful that a mouse who has eaten poison will return for more if it catches a whiff of the poison on another mouse’s breath, says behavioral scientist Bennett Galef of McMaster University in Hamilton, Canada. “The strength of this social learning on food choice is huge,” says Galef, whose research revealed that mixing CS2 with rat poison drew four times as many rodents to the bait.

Humans and most other primates lack GC-D cells. Our eyes are as important as our noses in helping us decide what to eat. GC-D cells are present in dogs and many other mammals and, if mice are an accurate model, their noses play an important role in determining their food preferences.

We’ve known that carbon disulfide was important in helping mice and rats identify food sources for a long time but their link to the GC-D cells is a new discovery. Bennett Galef’s earlier research on carbon disulfide led to its widespread use as an attractant in rat poison. He wrote:

By signalling “safety,” CS2 increases the attractiveness of materials to which it is applied.

Carbon disulfide may increase the effectiveness of poison baits in ways that extend beyond simple enhancement of initial intake. Results of 4 recent sets of experiments indicate that experience with the smell of a diet, either on the breath of a conspecific, or in association with CS2, interferes with rats’ ability to acquire a subsequent aversion (bait-shyness) towards that diet.

The GC-D cells’ influence on food preference could help explain why every time a new pup or foster dog who eats poop stays at our place the rest of the pack starts eating poop again too.

The use of carbon disulfide as an attractant in rat poison may explain why dogs are attracted to eating it.

It could also explain why my dogs have no interest in a new Nylabone until I spit on it, and why Audie likes to sniff our breath after we eat.

And – because humans lack GC-D cells, it may also help explain why we don’t understand dogs’ great interest in sniffing urine, stale breath and feces.

Pizza breath - Nom!

July 25, 2010 at 12:50 pm Leave a comment

Animal Attraction

I like to experiment with essential oils. I love perfume. Good perfume, not cheap drugstore stuff.  And essential oils not only give me a way to experiment with different scent combinations, I can also use them make my own scented soaps and cleaning products.

One day as I was playing around with mixtures of different scents while surrounded by a pack of curious dogs I thought “I wonder what the dogs think of these?”.

Anyone who’s spent a bit of time with dogs understands that they don’t make the same kinds of value judgments about smells that we do.  Seriously.  In case you have not already noticed the obvious, your dog adores smells like shit and week old garbage and rotting flesh and he probably thinks that smells like fabric softener and Glade air freshener are utterly revolting (just one more thing the dogs and I have in common).

It’s easy to find places where dogs and humans disagree on scent. I was interested in finding places where the dogs and I agreed.  So I collected a dozen or so vials of essential oils and four dogs (the number I had here at the time) and conducted an informal experiment. I put a drop of each oil on a small piece of paper then held the sample out toward each dog in turn and let each one decide whether they wanted to explore it more intimately or not.

The results were interesting.

Being courteous beasts, the dogs politely and carefully sniffed each sample I offered them. They seemed to react neutrally to most of the scents, generally taking a quick, cautious sniff or two then looking at me inquisitively*. All four turned their noses up at eucalyptus and preferred to avoid it. Three expressed similar distaste for tea tree oil and two for violet.  Wintergreen made one dog sneeze and the other three refused to sniff it. I didn’t force the issue.  They showed a somewhat marked interest in sandalwood, patchouli and ylang-ylang, taking a few extra sniffs and pausing between them as if to process the aromas.

The dogs were all mesmerized by three of the scents – vetiver, frankincense and oak moss with vetiver being the clear winner.  All four of them were entranced by it.  They didn’t just take a few polite whiff of the sample – they inhaled slowly and deeply then paused to process the aroma between each sniff. Charlie even tried to follow the bottle into the cabinet.

It was an interesting little experiment but I didn’t intend to follow up on it. That is, until last week. I was browsing aisles of beauty products while waiting for my stylist and while I don’t spend much money on that kind of thing (generally preferring utility to luxury) I sometimes like to check out scent products.

A row of bottles in the Aveda aisle caught my eye. Being somewhat paranoid about most over the counter scented products I sniffed each one cautiously. Most of were a lot sweeter and more citrusy than the scents I tend to prefer, but one hit the jackpot.  Chakra 1 is a blend of vetiver, frankincense (olibanum) and patchouli.  Strong and woody but not overpowering, it wasn’t something I’d ordinarily buy, but it was relatively inexpensive and given the results of my recent experiment I suspected that the dogs might enjoy it. So I brought a sample home.

I’m glad I did. Chakra 1 has been a big hit with the beasties. When I put it on they sniff me like a freshly decorated hydrant. And if I spritz a little on one of the dog beds, the boys will roll on it in apparent ecstasy.

I tend to prefer somewhat masculine grassy and woodsy fragrances rather than the fruity or flowery scents that dominate the market. Because the dogs and I seemed to have somewhat similar tastes, I decided to do another experiment and test their reactions to my perfume collection. While they were distinctly unimpressed by most of the products, Muschio di Quercia was everyone’s paws down favorite and young Charlie displays a clear and consistent interest in Privet Bloom**.

Most people probably think that testing animals’ reaction to perfumes is an odd idea, but it appears that I’m not the only one doing it. Or even the first to do it. Tuesday’s Wall Street Journal has the details:

Zoos have long spritzed perfumes and colognes on rocks, trees and toys in an effort to keep confined animals curious.

In 2003, Pat Thomas, general curator for the Wildlife Conservation Society’s Bronx Zoo in New York, decided to get scientific about it. Working with 24 fragrances and two cheetahs, he recorded how long it took the big cats to notice the scent and how much time they spent interacting with it.

The results left barely a whiff of a doubt. Estée Lauder’s Beautiful occupied the cheetahs on average for just two seconds. Revlon’s Charlie managed 15.5 seconds. Nina Ricci’s L’Air du Temps took it up to 10.4 minutes. But the musky Obsession for Men triumphed: 11.1 minutes. That’s longer than the cats usually take to savor a meal.

The results of Thomas’ investigation spread quickly through wildlife biology circles and now “Obsession for Men” is widely used in zoos and field investigations. It also appears that dogs aren’t unique in their interest in selected scent products. Perfumes are regularly used to attract and entertain cougars and other big cats, and footage from scent-baited camera traps indicates that coati, tapir and peccary were drawn to “Obsession” as well.

Ann Gottlieb, the “nose” who helped create Obsession for Men, thinks there could be a number of factors in the fragrance that wild animals might find irresistible.

“It’s a combination of this lickable vanilla heart married to this fresh green top note—it creates tension,” she says. The cologne also has synthetic “animal” notes like civet, a musky substance secreted by the cat of the same name, giving it particular sex appeal, she adds. “It sparks curiosity with humans and, apparently, animals.”

According to the online perfume reference guide basenotes, “Obsession for Men” includes topnotes of mandarin and bergamot;  heart notes of lavendar, myrrh, sage, clove, nutmeg and coriander and base notes amber, musk, sandalwood, vetiver and patchouli.

Combining Obsession’s formulation data with the results of the informal research on my dogs, I’ll say that if I was interested in animal attraction I would experiment with scents featuring simple sweet heart notes like vanilla, orange and lemon combined with strong animal and woody basenotes. Based on this hypothesis and a quick perusal of reviews at basenotes the perfumes I recommend for biologists and zookeepers are:

These products are all even more expensive than “Obsession for Men” so I doubt they’ll replace it in zoos and wildlife surveys. But if anyone wants to send me samples I’ll be happy to try them on the dogs and report the results {-;

* These “neutral” scents included blue tansy, tangerine, bergamot, clary sage, cedar, rose absolute, hay absolute, peppermint, agrimony, lavendar, orange and fir.

**Privet Bloom contains topnotes lemon, bergamot, verbena; white hyacinth as a middle note and base notes sea grass and cucumber.

June 10, 2010 at 12:33 am 14 comments

Piss on it!

Or… how do you keep packs of African wild dogs inside an  unfenced boundary?

Today Scientific American reports on a unique kind of barrier being used to keep African wild dogs inside the reserves designed to protect them.

Over the past year, [Craig] Jackson, a biologist, and his colleagues working on the Northern Tuli Wild Dog Project, have shown that strategically placed urine—called Bio-Boundaries—can help restrict the movements of these notorious fence-breakers in order to keep the endangered canines on protected land. “The fact that we’ve been able to contain these dogs is amazing,” Jackson says.

Keeping wild dogs inside the boundaries of preserves is important for their safety as well as for the safety of domestic goats and other animals the dogs often prey on outside the reserves.  African wild dogs hunt in packs like their cousins the wolves.  And they are remarkably successful at it.

Compared with lions, which successfully kill just 20 percent of the animals they stalk, wild dogs have a hunting success rate ranging from 40 to 80 percent. That’s not always a good thing for an animal that must coexist with humans and their livestock.

The wild dogs’ success at hunting is surpassed only by ours.  Humans are the number one killer of wild dogs, reportedly directly responsible for as much as 60 percent of all deaths.  We’re also indirectly responsible for the large number of deaths caused by diseases like parvo, rabies and distemper that wild dogs catch from their domestic brothers.

So keeping wild dogs inside the boundaries of game parks is vital to maintaining viable populations.  But how does one keep a bright, wide-ranging, atheletic species confined to a large, unfenced area?  Well it turns out that strategically placed urine samples do the trick quite nicely. The Botswana Predator Conservation Trust (BPCT) is conducting research with the goal of identifying the signaling chemicals in African wild dog territorial scent marks. According to their website:

The aim is to identify the chemicals in the scent mark odour that are sending the territorial “No Trespassing” signal and to use them to make artificial territorial boundaries that will protect wild dog packs by keeping them within the safety of protected conservation areas.  […]  African Wild Dogs, like nearly all mammals, send their social messages as complex mixtures of airborne organic chemicals, called semiochemicals. Wild dog packs stake out their hunting territories with patches of soil soaked with the urine of the pack’s alpha pair, and the odour of these scent marks tells neighbouring packs and itinerant dispersers “This area is occupied, no trespassing.”

BPCT’s goal is to use BioBoundaries to prevent human-wild dog conflicts.  And if they achieve their goal, parks won’t be the only areas where BioBoundaries area used.  Wild dog populations are in decline across Africa and problems with human predation and diseases spread by domestic dogs aren’t the only factors limiting their numbers.  As we’ve posted here before, wild dogs need to live in large packs and have access to interconnected ranges to survive as viable populations. They don’t just need room to hunt game – they also need safe migration corridors that allow populations to grow and mix.  BPCT hopes to use BioBoundaries to create genetic corridors between the healthy populations to allow genetic mixing to occur with minimal human intervention.


Smells like "No Tresspassing" to me

Will it work?  BioBoundaries are not an entirely new idea.  Semiochemicals have been used commercially for pest control decades.  According to SciAm:

In 1996 J. Weldon “Tico” McNutt, director of the Botswana Predator Conservation Trust noticed that it took a pack of dogs six months to move into a territory in Okavango that was left empty after four packs there were wiped out by rabies. He speculated that long-lasting chemicals in their urine and feces discouraged the dogs from entering those former territories, but never had the opportunity to the put his theory to practice. After all, it would not make sense to disrupt the behavior of healthy dog populations, and smaller populations were all kept within fences.

Finally, in April 2008, after 18 dogs were moved by conservationists to Tuli from Marakele National Park in South Africa, McNutt had his chance and Jackson was tasked with maintaining the bio-boundary and monitoring the animals’ movements with GPS-equipped dog collars. The researchers have flown more than 500 scent marks to Tuli over the last year, and the dogs appear to be staying within the bounds of the fenceless reserve.

BPCT hopes to identify and synthesize key components in wild dog territorial scent.  They believe that using laboratory-made scents would be more practical than collecting urine in the field. (Though I can’t help but wonder if collecting scent might be one way to employ local humans and make at least a few of them happy to have wild dogs in their back yard.)  If the project is successful, in the future  BioBoundaries might be used to control other large predators and territorial species.

Perhaps someday they’ll have formulas we can use to keep pests like deer, rabbits and the neighbors dog out of our garden too.

April 18, 2009 at 12:20 am 4 comments

Symbolic Understanding in Dogs

The use of symbols in communication has long been considered to be solely the domain of humans, great apes, cetaceans and a few bird species.  Human children typically start to understand basic vocal and gestural symbols at about a year of age.  By the time that most children are 2 to 3 years old, they are also able to understand the concepts of images and replicas.  As reported in Science News, a recent study demonstrated that dogs appear to be capable of a similar level of symbolic understanding.

Border collies quickly realize that their owners want them to fetch a toy from another room when shown a full-size or miniature replica of the desired item and given a command to “bring it here,” say biological psychologist Juliane Kaminski of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and her colleagues. Even a photograph of a toy works with some dogs as a signal to fetch that toy from an unseen location, the researchers report in an upcoming issue of Developmental Science.

Three dogs already trained to fetch objects succeeded on both replica tasks right away. Two untrained dogs got the hang of replica requests after a bit of practice.

“The most reasonable interpretation of dogs’ success in the replica tasks is that they understood that by showing a replica, a human was trying to communicate something to them,” Kaminski says. Dogs evolved a feel for how people communicate as a result of living in human settlements for thousands of years, she proposes.

Earlier studies have found that chimps, dolphins and other nonhuman animals have great difficulty retrieving objects after being shown replicas of those objects, even after many trials.

Dogs appear to have an innate ability to understand human gestures and body language.  Chimps (like the famous Washoe) and African Grey Parrots (like Alex) have demonstrated the ability to be taught sign or spoken language. Now it appears that Dr. Bonnie Bergin’s idea that dogs can learn to recognize and respond appropriately to written word and symbol cues may have been ahead of its time.  Her “teaching dogs to read” appears to be just a short step away from their now demonstrated ability to grasp the idea of images and replicas.

Coincidentally, I have been working with young Audie for a couple of months on these kins of exercises.  I’ve successfully taught him to search for, find and then bring me an item that matches one I’ve shown him.  We’ve done this with a wide range of objects (shoes, boots, metal bowls, pens, bumpers, spoons, business cards and more).  Sometimes the object I send him to find is in a different room.  Quite often I don’t know where it is (hence the need to have him find it).  Still, he gets it right nearly every time.

The question that arises from this is; are dogs innately capable of these kinds of symbolic learning skills or does the ability only arise from a certain degree of training?  I suspect it’s a combination of both.  SAR work (like explosive and narcotics detection work) takes advantage of a dog’s ability to use scent as a symbol for the object he’s seeking.  In Learning to Smell, Donald Wilson and Richard Stevenson propose that smells “are outcomes of highly synthetic, memory-dependent processing that is further modulated by expectation, context, and internal state”  and they compare the process of learning how to smell to that of learning how to read.

Perhaps the combination of being a neotenized, highly social, scent-reading species that co-evolved with humans and has an innate skill to observe and interpret our behavior makes dogs uniquely well-equipped for certain types of symbolic learning. How much are they able understand?  Well, since they’re poorly equipped to talk or sign back to us we’ll have to wait a while longer to find out.

I’ll try to shoot and upload some video of Audie and I working on the “match game” this week.

March 22, 2009 at 4:07 pm 4 comments

How Does Your Dog Smell?

No, I’m not blogging about canine olfactory processes. I’ll leave that to Ken over at Did a Cat Sh*t in Here

I’d like to talk about how you recognize and judge the scent of your four-legged friend.


Back in 2000, Queens University psychologists Deborah Wells and Peter Hepper published a study in Perception titled The discrimination of dog odours by humans.  The study examined the ability of humans to identify individual dogs by smell. From the abstract:

Most of the participants (88.5%) were able to recognise the odour of their own dog. They showed no significant bias, however, in responding which of the odours they thought smelt the strongest or most pleasant. The results indicate that dogs produce odours that are individually distinctive to their owners, and highlight the fact that humans can recognise members of another species using olfactory cues — an ability presumably acquired without conscious effort.

Even though the importance of our sense of smell has historically been grossly underestimated, we’ve known for some time that humans, like other mammals, can discriminate between kin and non‐kin by olfactory cues alone — so these findings shouldn’t be terribly surprising.  Still, after stumbling onto the abstract I was curious to know more.  Since the article is only available (at least to me) by paid subscription, I thought it was a wonderful stroke of luck that Scientific American published an article about it  just this week. Here’s their description of the study and an interesting side note on the results not included in the abstract:

In this study, twenty-six dog owners were given a blanket to place in their dog’s bed for a period of three consecutive nights. (One rule was that the dogs couldn’t be bathed for at least a month before the study began.) The owners then returned to the laboratory with this blanket, were blindfolded, and asked to take a deep whiff of two comparison blankets. One blanket was from their own dog’s bed and the other was from the bed of a foreign dog matched for age, sex, and (wherever possible) breed. Remarkably, 88.5% (23 of the 26 participants) correctly identified their own dog’s odor—a finding that the authors attribute to familiarization. However, somewhat surprisingly, the study failed to show that owners preferred this particular smell over the other one.

So… pet owners can differentiate the scent of their dogs from those of strange dogs (which is, by the way, not the same thing as being able to identify our dogs by smell) – but we don’t necessarily preferour dogs’ odors. Why not?  Well first, as SciAm noted:

One possible reason for this null finding on the preference dimension may be that the study did not control for quality of attachment between the owner and his or her dog.

They probably also didn’t control for variations in personal or cultural attitudes toward odor or for factors affecting the general aesthetic quality of the odor of the dog (i.e., gingivitis, skin problems, flatulence, ear infections etc.) Pheromones may be an important factor as well.  While we may recognize and/or be attracted to the body odors of potential mates and our offspring, it would make evolutionary sense that we wouldn’t necessarily respond positively to the pheromones or body odors of an animal of another species — even one that we care deeply for.

I enjoy the smells of my dogs (for the most part at least) and I’ve always been able to tell them apart by scent.  Just for you I very carefully and methodically smelled both my dogs about the head, shoulders and hips so I could report what they smell like.  Zip has a very soft, light, powdery (and very undoglike) scent with hints of lemon and ear wax.  This is her scent, not her shampoo — she hasn’t had a bath in several months (and no, I don’t use doggy colognes).  Audie has a much stronger, saltier scent with an earwax topnote and basenotes of intact boy dog urine and raw meat.  

I have to say that even though Audie is my darling mamma’s boy, I much prefer Zip’s scent to his.

January 8, 2009 at 1:04 am 5 comments

Now Smell This

Our friend LabRat over at AtomicNerds wrote an excellent post a while back on why the mirror test for self-awareness may not be applicable to dogs – or bats.  Here’s a little sniff:

Personally, however, I’ve always had an issue with the test, because it depends rather heavily on something humans take for granted- vision as the dominant source of sensory information. The fact that dogs never pass the mirror test is something that is frequently mentioned in dog behavior literature as proof that dogs have no self-awareness, no conception of “I” and “you”, that they just learn from stimulus and response. It’s extremely important for humans to bear in mind that dogs don’t think or feel or remember the way humans do, but I really wonder first if a total absence of self-awareness is a logical assumption to make of a complex social animal, and second if the test is a fair measurement of an animal like a dog. (Or, for that matter, a horse or any other complex social animal that has failed the test but doesn’t put much reliance on its eyes compared to other senses.)

For a dog, smell is the ruling sense, the chief and most reliable source of information. Not only is the sense of smell of the average dog (let alone a hound) at least a hundred times more powerful than it is for humans, it’s gives them even more information than vision does for us, because scent is the only three-dimensional sense- it doesn’t just tell them what’s going on now, it also tells them what happened then. We can approximate it by taking clues from our vision and reasoning through them, but we can’t tell that someone was standing someplace an intermediate period of time ago (but is gone now) without going through that reasoning process and doing CSI tricks. For a dog, this is standard information, part of the way they hunt naturally.

There’s no doubt about it, in a dog’s world, scent is king.  Interested in new opportunities to share the fascinating world of scent with your dog? Tired of the same old routine of tracking and hide-and-seek?  How about a scratch and sniff book designed just for dogs?  Each page in “See Spot Smell” includes a word, picture, and smell that, according to the author, your dog will recognize.  Linking scent to reading skills? Wait – is this a ploy to incorporate olfactory learning into a program to teach dogs to read?

I don’t know.  Considering where our economy appears to be headed, if I’m going to spend a bunch of time doing scent work with my dog I don’t think I’ll waste it using pictures of cheese to teach him to read – I’m going to train me a MONEY DOG!

According to their press release:

Money Dog’s Dog-Training Money Scent teaches dog to recognize and find cash. Using dogs natural ability to recognize unique scents, this training scent turns the ordinary household pet into a money dog.  “Any dog” can detect training scents for deer, rabbits or pheasant. Now your dog can detect this training scent, and detect cash. Money Dog’s Dog-Training Money Scent is perfect for games with your dog, a new tracking and trailing job for your dog, or simply to find cash.

Dog training scents come in many different styles and scents, but Money Dog’s Dog-Training Money Scent is the only dog-training scent which uses real cash to produce the unique scent.  Each 4.0 ounce bottle contains an extract of genuine cash, and is re-sealable. Because the training scent is made from cash, the fluid is not for human or animal consumption.

Gen-you-win cash extract! How cool is that? Hmmm, I wonder… if my dog can’t learn to find money using the extract, can I reconstitute it and turn it back into cash?

A money dog sounds like just the ticket. But let’s see how my buddy Audie feels about the program.  I’ll get an appropriate book, a piece of cheese and some cash and we’ll see which one he’s interested in:

I present the problem

I present the problem

Audie considers the options

Audie considers the options


He makes his choice

He makes his choice

...and shows me the money!

...and shows me the money!

October 26, 2008 at 7:28 pm 2 comments

Common Odorants Not People- or Pet-Friendly

Today’s 60-Second Science podcast from Scientific American exposes some eye-opening information on the odorants added to products like detergents and air fresheners.  Apparently, the manufacturers of these products are not required to list all the ingredients in their them.  So — instead of listing all the odorant chemicals in the product, the labels often simply state that they contain a “mixture of perfume oils.”  Thanks FDA!

After hearing that many people reported feeling sick when exposed to strong scents in many of these products (count me in as one of those people – I DETEST artificial odorants), Dr. Anne Steinemann of University of Washington analyzed several of the products.  From SciAm:

According to her report in the journal Environmental Impact Assessment Review, plug-in air fresheners, scented sprays, dryer sheets and detergents all contained a mixture of volatile organic compounds.

(…) five out of the six products Steinemann tested emitted one or more so-called hazardous air pollutants, which are carcinogens determined to have no safe exposure level by the EPA.   While the study did not test for any human health risk from exposure to these chemicals, Steinemenn says the next time the air in the house smells stale, maybe you just open a window. reported that:

Steinemann decided to do the study, she tells WebMD, after receiving more than 200 consumer complaints about side effects from fragranced products.

“I actually witnessed someone having a seizure when exposed to an air freshener,” she says. She picked six fragranced products — laundry detergent, fabric softener, dryer sheets, and air fresheners in solid, spray, and oil form.

In a laboratory, she put each product in an isolated space at room temperature. Then she analyzed the surrounding air for volatile organic compounds (VOCs) — small molecules that evaporate from the surface of the product into the air. She used advanced methods called gas chromatography and mass spectrometry to identify the VOCs.

Thank you Dr. Steinemann for reminding my why I gave up fabric softeners and now make my own laundry detergent and air freshener spray.  Also big thanks to bff Audrey who made me a couple of batches of laundry detergent (one liquid and one dry), gave me a kit and some recipes and got me hooked on the best, cleanest — and cheapest — way to clean clothes. reports that:

In the current study of the six products, Steinmann found almost 100 different VOCs emitted by the products under scrutiny.  None of the products listed any of the toxic ingredients on their labels.  Of the six products, five of them emitted at least one carcinogenic substance classified as a “hazardous air pollutant” by the Environmental Protection Agency (EPA) and for which there is no known safe level of exposure.

Of all the VOCs revealed in Steinmann’s analysis, 58 of them tested above the 300 micrograms per cubic meter mark, a level considered hazardous or toxic for them all, according to EPA standards.  The plug-in air freshener alone emitted more than 20 VOCs.  The product’s label listed these toxic VOCs as simply a “mixture of perfume oils.”

There are no regulations in the United States that require ingredients labels to list all substances used in the manufacture of personal care and grooming products, laundry products, and air fresheners.  The US Food and Drug Administration (FDA) requires an ingredients list for cosmetics but no federal agency requires a list of the chemicals required to produce the fragrances the cosmetics or other products emit.

So, let’s get this straight.  If I am buying a personal care or grooming product, a laundry product, or an air freshener — the FDA doesn’t care what kind of toxic waste ingredients the manufacturer puts in it?  Lovely.

In a bit of unfortunate (for the manufacturer, Proctor & Gamble) timing, Febreze issued a PR release last week announcing their new “pet-friendly collection.”  The release states that:

Febreze, the leading line of home freshening products and a favorite among pooches and purrs, is extending its revolutionary Pet Odor Eliminator technology into a complete pet-friendly collection. Febreze Fabric Refresher and Air Effects Pet Odor Eliminator offerings will be joined this summer by Febreze Candles Pet Odor Eliminator and Febreze NOTICEables Pet Odor Eliminator, delivering breaths of fresh air to pet-loving homes across the country.

Unlike many air fresheners that just cover up pet odors with a heavy perfume, Febreze Pet Odor Eliminator products eliminate pet odors in the air while at the same time delivering a light, fresh scent. Febreze has come full circle with the entire line, now offering pet owners a wider array of tools to de-stink and freshen up, while maintaining a happy and healthy home for their furry loved ones.

Happy maybe.  Healthy — now that’s debatable.  Given the results of Dr. Steinemann’s research, I think I’ll either open my windows to blow bad odors out of my home, or I’ll use a home-made essential oil spray to cover them up.

August 15, 2008 at 5:00 pm 3 comments

Because A Dog’s Mind is a Terrible Thing to Waste


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