Some Recent Conversations re. Dog Smell
The following (first) message has prompted considerable discussion relevant to our Taste of Smell site. Some of this discussion is archived here. My choice of selections was based on novel information so this may be of use as a raw data resource. Good luck...
Date: Tue, 19 Dec 1995 12:35:13 -0500
From: SRLindsay@aol.com
Subject: Olfactory questions
Dear Scent-L Subscribers:
I have a few technical questions about olfaction which I hope to have
answered or, perhaps, receive leads in terms of scientific references,
ongoing research, etc.
(1) To my knowledge lateralization/localization by internostril differences
of odorant concentration/delay has not been demonstrated in the dog. Only
one successful study in humans appears to exist (Bekesy) and a couple of
interesting reports concerning snakes (Schwenk). Do such experiments exist
for the dog? Does the superior colliculus play a role in olfactory
localization?
(2) How many glomeruli are in the dog's olfactory lobes and do these numbers
correspond in ratio to the number of olfactory neurons in the dogs olfactory
epithelium? Axel et al. have found at least1,000 different olfactory
receptors with axonal projections to specific glomeruli sites -- are the
individual glomeruli specialized for the detection of specific odors?
(3) Does the trigeminal nerve play a role in olfaction?
(4) Any theories on how the dog determines the direction of a track when it
is detected at points other than the beginning?
(5) How does the tracker dog cope with olfactory adaptation/habituation --
any theories?
(6) Olfactory neurons expressing specific receptors project axons to
specific glomeruli in the olfactory bulbs. Since olfactory neurons are shed
and replaced every 6 weeks or so how do the new axons find their way to the
correct glomeruli?
Responses to the above questions would be greatly appreciated -- please
include relevant references.
Best regards,
Steve
Steve Lindsay
Canine Behavioral S
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Tue, 19 Dec 1995 15:23:01 -0600
From: Julie Jones
Subject: Re: Olfactory questions
Hello Steve:
At my home I have a book that I think would be of great interest to you:
SCENT AND THE SCENTING DOG by: William G. Syrotuck. If you do not have
this book already, I think this would answer some of your questions. I had
to order this book from a bookstore as I could not find a bookstore that
carried it in the store. Check at your local bookstores. If for some
reason they cannot get it for you (they should be able to), please be in
touch with me and I will send my copy to you. If I recall, the price was
around $11.00.
I will try and remember to bring the book into work with me tomorrow just in
case you can't get the book or you want me to send it to you.
- Julie R. Jones -
XXXXXXXXXXXXXXXXXXXXXx
Date: Tue, 19 Dec 1995 15:34:00 -0600
From: "Lawrence J. Myers"
Subject: Re: Olfactory questions
Ok, I'll give it a shot. Although it's disappointing to find out how little
is known.
>(1) To my knowledge lateralization/localization by internostril differences
>of odorant concentration/delay has not been demonstrated in the dog. Only
>one successful study in humans appears to exist (Bekesy) and a couple of
>interesting reports concerning snakes (Schwenk). Do such experiments exist
>for the dog?
Not to my knowledge, although it's certainly been discussed among interested
researchers.
Does the superior colliculus play a role in olfactory
>localization?
Unknown, at least by me, but I suspect that it's unknown in general.
>
>(2) How many glomeruli are in the dog's olfactory lobes and do these
numbers
>correspond in ratio to the number of olfactory neurons in the dogs olfactory
>epithelium? Axel et al. have found at least1,000 different olfactory
>receptors with axonal projections to specific glomeruli sites -- are the
>individual glomeruli specialized for the detection of specific odors?
>
The work of Axel, et al. is fairly recent, if they're the articles I think
to which I think you're referring. There is some ongoing work here (by a
colleague, Don Buxton) on the interconnectivity of the glomeruli and the
mucosa, but it hasn't progressed that far.
>(3) Does the trigeminal nerve play a role in olfaction?
Yes. The precise role is one which is still argued, but I believe that it's
generally accepted that it plays some role, at least.
>
>(4) Any theories on how the dog determines the direction of a track when it
>is detected at points other than the beginning?
>
Sure.
First note that it has been suggested through research that many dogs do
not, in fact, reliably follow the track in the correct direction (Brisbin,
Animal Behaviour, 1994). On the other hand, it has been suggested by
competing research that many dogs do follow a track reliably in the correct
direction (I don't have the reference at hand....It's authored by a number
of British scientists, and published around '93-95).
The major hypothesis (let's not call it a theory, yet.. too little research
so far) I like is that dogs are trained in most systems to follow odor
concentration gradients from the weakest to the strongest, thus pinpointing
the source. Of course, there are other important issues, such as what is the
dog detecting as an odor source?
>(5) How does the tracker dog cope with olfactory adaptation/habituation --
>any theories?
Oy! None I know that I really like. There is no question that dogs undergo
olfactory adaptation (Myers, et al., Electro-olfactography, etc., American
Journal of Veterinary Research, 1984). Some have suggested otherwise, but
not through research. In addition some have suggested that the pattern used
by many dogs in tracking (crossing over the track and off repeatedly and
rapidly) may decrease opportunity for adaptation.
>
>(6) Olfactory neurons expressing specific receptors project axons to
>specific glomeruli in the olfactory bulbs. Since olfactory neurons are shed
>and replaced every 6 weeks or so how do the new axons find their way to the
>correct glomeruli?
If I really knew this one, I might be nominated for the Nobel :) The
olfactory system is the only portion of the adult nervous system in which
new neurons are formed, so understanding this is of considerable importance
for biomedical reasons. That's a VERY tough question and has several
possible answers.Two major ones- 1)- cellular architecture forces growth
through the pre-existing channel. 2)- there is a chemotaxic factor in the
neural target which is recognized by the replicating neuron.
>
>Responses to the above questions would be greatly appreciated -- please
>include relevant references.
>
>Best regards,
>
>Steve
>
>Steve Lindsay
>Canine Behavioral Services
>Philadelphia, PA
I hope these attempts help.
Larry
Lawrence Myers
Associate Director, Institute for Biological Detection Systems
410 Greene Annex
Auburn University, AL 36859-5532
(334) 844-4237
XXXXXXXXXXXXXXXXXXXXXXXXX
Date: Tue, 19 Dec 1995 17:45:52 -0500 (EST)
From: Heather E Houlahan
Subject: Re: Olfactory questions
Steve --
I'll take a stab at what I can here. I've forwarded your message to Ken
Chiacchia, my resident biochemist and scent expert dude. With luck, we
will soon find the pile of scent references that have been (apparently)
concealed in a box since we moved. Ken thinks he can help out on
question 2.
> (4) Any theories on how the dog determines the direction of a track when
it
> is detected at points other than the beginning?
>
We have observed dogs approaching the middle of a trail at right angles
to it move their heads back and forth before choosing a direction.
Snakes utilize the two lobes (analog to two nostrils, which might bear on
question 1) of their vomernasal organ to determine the direction taken by
prey. Each tongue fork inserts scent molecules directly onto the right
or left lobe. It is unknown whether dogs use the vno to determine
direction, or can do so with their noses alone.
> (5) How does the tracker dog cope with olfactory adaptation/habituation --
> any theories?
Airscenting dogs may move across a scent cone in order to "refresh" at
the edges -- i.e. provide contrast to the scent at the middle of the
cone. A trailing dog could do the same thing by keeping tabs on the
background scent at the edge of a scent trail. A caution for those who
insist that their dogs must track "close."
Does anyone become habituated to a scent we are actually seeking? (i.e.
is this a chemical process or a neurological one?)
yours,
Heather Houlahan
Allegheny Mountain Rescue Group
Search Dogs Northeast
XXXXXXXXXXXXXXXXXXXXX
Date: Tue, 19 Dec 1995 19:09:32 -0500 (EST)
From: Heather E Houlahan
Reply to: scent-l@txk9cop.metronet.com
To: Multiple.recipients.of.The.Scent.Training.List@metronet.com
Subject: FYI -- forward of response to olfactory questions
You'll need to reference Steve's original message on olfaction for the
questions to these answers. But I thought some of you might be
interested in this technical discussion.
I've often lamented the lack of controlled scientific research on canine
olfaction. But then, I'm not letting some geek in a lab coat excise MY
dog's vno for the interests of science. So rats and snakes it is. Sorry
guys.
-- HH
---------- Forwarded message ----------
Date: Tue, 19 Dec 1995 18:50:08 -0500 (EST)
From: Kenneth B Chiacchia
To: srlindsay@aol.com
Cc: houlahan+@pitt.edu
Subject: scent questions
I'll take a stab at some of your questions, although in many cases it
looks like you have information that's at least as good as mine:
1) I've seen the Schwenk paper, but not the Beskey paper. Could you sent
me the reference for the latter? As far as I know that experiment, like
many, hasn't been done on dogs, but the idea has been floated that
nasal-to-nasal differences might play a role in detecting the direction
in which scent is getting stronger (more about this with your later
questions)
2) In answer to this question, individual olfactory nerve cells do map to
specific glomuleri in the olfactory lobe, but I think that there are
many more
receptors/incoming signals than there are glomuleri. Each glomulerus
contains multiple synapses, which I believe do map to specific,
individual parts of the olfactory lobe. You want to look at the work
of Linda Buck, a former Axel student who's now a prof at Harvard Medical
School. She's shown that the regions of the olfactory lobe are
specialized just as the olfactory nerve cells that actually diplay the
odorant receptors; specific odors are picked up in specific areas of the
olfactory epithelium, and the neural signal travels to specific areas on
the olf. lobe. The only trick is that areas sensitive to different
odorants overlap: it's not like there's a purely "sour" smell area that
detects acids. No one knows how many receptors each olf. nerve cell
carries, but the number is small: perhaps only one.
The only part of the question I didn't get is the part about the superior
colliculus. My sources say it's involved in visual reflexes, not
olfactory: do you have something more up to date? Please email back any
references you have, I'd like to hear more.
3) The trigeminal, or 10th cranial, nerve carries sensory input from a
bunch of tissues, including the tongue, but not olfactory input, as far
as I know. That's the domain of the olfactory, or 1st, cranial nerve.
Again, if you've read differently I'd like the references.
4) I know of one study, from Scandinavia, that looked at dogs tracking on
pavement; when the dogs hit a trail, they travel along one direction,
sniffing at a high rate. If the scent gets stronger, they settle down in
their usual sniff rate. If it gets weaker, they turn around and go the
other way.
The big problem with this study is that some more experienced trailing
handlers (I've only done air scent) tell me that experienced dogs hit the
right direction right away; this might be your left nostril/right nostril
thing at work, and it's possible that a more experienced dog might be
able to better sense a slight difference in each nostril.
I'm sorry I can't give you the reference for this, as I've temporarily (I
hope) lost the folder I had it in. Email me later; hopefully I'll find
it soon. But it was from one of the Scandinavian countries, it was
relatively recent, and I got it from the MEDLINE database using either
"smell" or "scent" as a keyword.
5) Professional perfume workers keep from getting habituated by moving a
scent between each nostril. I don't think dogs do this, but what they DO
do is weave back and forth across a trail/air-scent plume. Research on
moths following a pheromone trail (sorry, I don't have the ref, but it
was in either Science or Nature and in the 1990s) suggests that, by
crossing the central (most intense) part of a scent trail and then going
back to the less intense "shoulders," you avoid habituation. This would
also help determine whether you're moving in the right direction, as per
the Scandinavian dogs above. I'm not aware of any studies testing this
hypothesis.
6) If I knew the answer to that question, I'd be living on my private
estate surrounded by the trappings of wealth. This is the number one
question in neuroscience: how do developing axons find their targets?
We know that, during fetal development, nerves form many more connections
than they need; the ones that aren't productive die off. The ongoing
replacement of olfactory nerve cells, one would think, must be performed
with a little less trial and error. In both cases, probably the
developing
axon and the synapse it has to go to, which is missing an incoming axon,
secrete growth factors that attract each other.
If we could crack this one, we might be able to reconnect the nerve cells
in severed spines and lots of other wonderous things. A LOT of people
are putting money and effort into it, and they may be getting warmer.
XXXXXXXXXXXXXXXXXXXXXx
Date: Wed, 20 Dec 1995 00:12:43 -0500
From: SRLindsay@aol.com
Subject: Re: Olfactory questions
Dear Larry
Thank you for your detailed response to my questions. A few years ago I had
the pleasure of listening to a lecture presented by you at an AVMA meeting in
Minneapolis.
At that time you described an interesting metaphor to illustrate the dog's
ability to detect butyric acid (I think) in dilution. As I recall, you
suggested that the dog could detect a single molecule of this substance
suspended within a specific area (?), but then went on to describe an
incredible metaphor in which a certain amount of the odorant was diluted in
water. According to the metaphor, the dog could detect it in an expanse of
water a foot deep (?) and covering a surface area equivalent to that of a
state the size of Washington/Oregon (?)
Do your recall these comparisons? Would you mind refreshing my memory -- the
image left a lasting impression but I've forgotten the details.
Thank you again for your opinions and information.
Best regards,
Steve
Steve Lindsay
Canine Behavioral Services
Philadelphia, PA
XXXXXXXXXXXXXXXX
Date: Wed, 20 Dec 1995 00:12:57 -0500
From: SRLindsay@aol.com
Subject: Re: Olfactory questions
Julie Jones wrote:
.At my home I have a book that I think would be of great .interest to you:
.SCENT AND THE SCENTING DOG by: William G. Syrotuck. If you .do not have
.this book already, I think this would answer some of your .questions.
Dear Julie,
Thank you for the book reference.
Steve Lindsay
XXXXXXXXXXXXXXXX
Date: Wed, 20 Dec 1995 00:13:37 -0500
From: SRLindsay@aol.com
Reply to: scent-l@txk9cop.metronet.com
To: Multiple@metronet.com, recipients@metronet.com, of@metronet.com,
The@metronet.com, Scent@metronet.com, Training@metronet.com,
List@metronet.com
Subject: Re: Olfactory question
Dear Kenneth and Heather,
Thank you very much for the detailed response to my questions. In my turn,
I'll attempt to respond to the questions you raised. The von Bekesy article
is actually quite interesting, but not without criticism -- apparently the
study could not be duplicated (Cain, 1988 -- Steven's Handbook of
Experimental Psychology). This is an important area that should receive
greater experimental attention. Determining whether
localization/lateralization exists would seem to be a fairly straight-forward
problem to approach experimentally.
The reference to the superior colliculus (SC) regards its role in
multisensory (hearing, sight, and touch) integration and localization. In
Kandel et al. (1991) Fig 34-6, there appears to be a path from the olfactory
tract projecting through the superior colliculus -- but it is not clear
whether synapses are formed there or not. My thought was that the SC might
mediate olfactory localization as well, perhaps through the trigeminal nerve
(part of the tactile system).
I think that the reference that you were referring to with regards to
directional tracking was Thessen et al. (1993). An earlier series of
experiments by Steen and Wilsson (1990) are also of interest. I think your
hypothesis concerning habituation is very reasonable. I wonder, though, in
the case of the dog whether a certain percentage of olfactory neurons are
held in reserve by a gating-feedback mechanism of some sort, so that as the
working receptors habituate other more fresh neurons might be recruited into
action.
I'm struck by the experimental opportunities evident in the olfactory neuron.
To my knowledge it is the only neuron that is capable of duplication after
birth. Perhaps, by targeting research on the mechanism allowing the
olfactory cell to duplicate, important knowledge could be obtained for the
restoration of destroyed brain tissue resulting from injury, stroke, disease,
etc. This possibility complements your suggestion concerning the axonal
projections of these cells and its potential relevance with respect to the
repair of severed nerve fibers.
Thanks once again for sharing your expertise.
Best regards,
Steve
Steve Lindsay
Canine Behavioral Services
Philadelphia, PA
Kandel ER (1991). Principles of Neural Science (3rd Ed). New York, NY:
Elsevier.
Steen JB and Wilsson E (1990). How do dogs determine the direction of
tracks? Acta Physiol Scand, 139:531-534.
Thessen A, Steen JB, Doving, KB (1993). Behaviour of dogs during olfactory
tracking. J Exp Biol, 180:247-251.
Von Bekesy G (1964). Olfactory analogue to directional hearing. Appl
Physiol, 19:369-373.
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx
Date: Wed, 20 Dec 1995 00:18:36 -0500
From: MSKoenig@aol.com
Scenting Dog
I carry SCENT AND THE SCENTING DOG and have a number of copies on hand. If
you want a copy, send $11 (includes postage) to: Marcia Koenig, PO Box 625,
Redmond, WA 98073.
XXXXXXXXXXXXXXXXX
ate: Wed, 20 Dec 1995 08:42:16 -0600
From: "Lawrence J. Myers"
Reply to: scent-l@txk9cop.metronet.com
To: Multiple.recipients.of.The.Scent.Training.List@metronet.com
Subject: Re: FYI -- forward of response to olfactory questions
A correction to make in Dr. Chiacchia's response: The trigeminal is the
fifth cranial nerve, not thee tenth , and the etmoid and palatine branches
of the trigeminal innervate the nasal cavity and are responsible for some
aspects of "smell".
In general, I concur.
Lawrence Myers
Associate Director, Institute for Biological Detection Systems
410 Greene Annex
Auburn University, AL 36859-5532
(334) 844-4237
XXXXXXXXXXX
Date: Wed, 20 Dec 1995 20:08:11 -0500
From: AustShpds@aol.com
Subject: Re: Scent and the Scenting Dog
Just a note, to all you who are unaware of this source, I just got my new
Direct Books catalog.....
They've got 20 different titles under "Tracking", four of which are videos.
Also, 8 additional titles under SAR, one of which is a video. In addition,
there's 17 titles under Police Work, nine or which are videos. This doesn't
include SchH or all the other subject headings. If nothing else, they are an
excellent resource at much better than bookstore prices. (Most bookstores
don't even come close to having most of these titles anyway.)
They can be contacted
by phone at: 1-800-776-2665
or faxed at: 1-509-662-7233
or on the internet at: dgctbook@cascade.net or
Compuserve:750027,3255
Just passing along the info. It's a good thing hubby doesn't read the VISA
statements!
Jill
XXXXXXXXXXXXXXXXXXXXXXXXXx
Date: Wed, 20 Dec 1995 16:24:39 -0600
From: "Lawrence J. Myers"
Subject: Re: Olfactory questions
:::GRIN::: Everyone remembers that damnned analogy :)
It wasn't my analogy, and I won't vouch for the accuracy. It was proposed
and provided by Esso Resources Canada, Ltd. while marketing their pipeline
leak detection system which uses dogs and a proprietary taggant. It was: If
the state of Washington was covered entirely with two feet of water, a dog
can detect one teaspoon (or tablespoon, I forget) dissolved in that water.
I don't know about that, but I did some of the research for the system, and
the dogs could detect their taggants at embarassingly low concentrations as
measured by a solvent dilution technique and EEG and behavioral olfactometry.
I thought your name was familiar.... we'd met before. I'm getting old and
absent-minded.
Larry
Lawrence Myers
Associate Director, Institute for Biological Detection Systems
410 Greene Annex
Auburn University, AL 36859-5532
(334) 844-4237
XXXXXXXXXXXX
Date: Thu, 21 Dec 1995 03:15:42 -0500
From: WNYSRCHDOG@aol.com
m
Subject: Re: Olfactory questions
Steve this may be of interest to you. Erin this is a good example of scent
work and its powers.
(c) 1994 SIRS, Inc. -- SIRS Researcher
Volume : SIRS 1991 Applied Science, Article 55
Subject: Keyword(s) : SCENT and DOGS
Title : Sleuths for All Seasons
Author : Juliet A. McGhie
Source : Lamp
Publication Date : Spring 1991
Page Number(s) : 26-29
XXXXXXXXXXXXXXX
Date: Thu, 21 Dec 1995 12:15:01 -0500
From: SRLindsay@aol.com
Reply to: scent-l@txk9cop.metronet.com
To: Multiple@metronet.com, recipients@metronet.com, of@metronet.com,
The@metronet.com, Scent@metronet.com, Training@metronet.com,
List@metronet.com
Subject: Olfaction and hormones
Dear Scent-L Subscribers,
I have a number of questions regarding the effect of hormonal influences on
olfactory performance. I would greatly appreciate comments together with
references where applicable. But first a brief preface:
Pietras and Moulton (1974) found evidence of olfactory acuity fluctuations
occurring during the rat's estrous cycle. Further, the study revealed that
estrogen activity tended to facilitate olfaction while progesterone tended to
depress it. Also, females injected with testosterone performed significantly
better than controls and better yet as the dose was increased. Further, the
study found that male rats performed olfactory detection tasks at
significantly better level than ovariectomized females. The authors conclude
that androgens play a significant role in facilitating olfaction in the rat.
The above study raises a number of interesting and controversial questions.
(1) What, if any, hormonal influences affect the dog's ability to smell?
Further, what mechanisms mediate this effect?
(2) Are there any significant effects on performance, reliability, tenacity,
etc. as the result of castration or spaying in the working dog?
(3) Are there demonstrable olfactory differences between males and females?
Do female dogs exhibit more or less olfactory reliability (detection
thresholds) during their estrus cycle?
(4) Do corticosteroids affect olfactory performance? If so, what mechanism
mediates the effect? Also, a related question, does stress impact on
olfactory performance?
(5) Are all odorants equally detectable regardless of sex or are males
better at detecting some smells and females better at detecting others?
Reference
Pietras RJ, Moulton DG (1974). Hormonal influences on odor detection in
rats: Changes associated with the estrous cycle, pseydopregnancy,
ovariectomy, and administration of testosterone propionate. Physiol and Beh,
12:475-491.
Thank you for considering the above questions and sharing your
knowledge.
Best regards,
Steve
Steve Lindsay
Canine Behavior Services
Philadelphia, PA
XXXXXXXXXXXXXXXXXXXx
Date: Fri, 22 Dec 1995 08:32:08 -0800 (PST)
From: "Morris R. Atwell"
Subject: Re: Olfactory questions
I am interested in a summary on 'track direction'!
Interesting note: Normally in tracking the dog is always started at a scent
pad with the direction of the track obvious. I will have to try doing some
tracking where I start my dog in the middle of a leg and see what happens?
Will she pick the right direction every time and who long will it take to
sort out the direction? Or, will I have to train her to go in the right
direction?
When on a search, I can tell when my dog hits a 'trail', where someone has
walked. In those cases where I know someone has been by this place and the
direction of travel - my dog always goes in the right direction. She does
take a few feet to sort out direction of travel.
I have also read some articles on how a dog tracks 'ground crush' and not
scent from a person. This was demonstrated with a trained tracking dog.
An article was dragged along the ground using 2 ropes so there would be no
human scent on the track. Dog tracked exactly where the article had
distrubed the ground.
Another test was to lay a track with a 45 degree turn in it. Have another
person intersect this track at the 45 degree turn. This way the dog
approaches a 'Y' in the track. When the track is less that 2 hours old
the dog will make a right decision and follow the correct track. If the
track is more than 2 hours old, it is 50/50 on direction, IF the weight
of the 2 track layers is with 20 lbs of each other! If there is more
than 20 lbs difference in track layers the dog always makes a right
decision.
morris@crl.com
XXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Fri, 22 Dec 1995 18:48:08 -0500
From: SRLindsay@aol.com
Subject: Re: Olfactory questions
On Fri, 22 Dec 1995, Morris R. Atwell wrote:
>
> I am interested in a summary on 'track direction'!
>
> Interesting note: Normally in tracking the dog is always started at a
scent
> pad with the direction of the track obvious. I will have to try doing some
> tracking where I start my dog in the middle of a leg and see what happens?
Hi Morris,
Did you see the post "Directional tracking" that I sent a couple days ago?
It includes a brief summary of 3 studies involving directional tracking.
It may be of interest to some of you in the Philadelphia area who have
tracker dogs to contact Dr. William Carr at Beaver College. Dr. Carr has
performed a number of interesting olfactory studies over the years and is
currently testing and evaluating directional tracking abilities in dogs.
Surprisingly, most of the dogs he has evaluated so far fail to choose the
correct direction above a chance level when tested on grass, but do much
better indoors when tracks are laid on paper. Directional tracking is
facilitated when the track layer hesitates (3 to 4 seconds) between steps.
Such enhancement of the track-polarity support a scent intensity-gradient
hypothesis (Miller et al., 1995). Persons interested in more information
about his work can contact him at the following address:
Dr. William Carr
Department of Psychology
Beaver College
Glenside, PA 19038
Reference
Miller EJ, Houghton R, Carr WJ (1995). Chemosensory directional tracking in
dogs (Canis familiaris): Enhancing the track's polarity. Presented at the
meeting of the Assoc of Chemoreception, Sarasota, FL, April 19, 1995.
Best regards,
Steve
Steve Lindsay
Canine Behavioral Services
Philadelphia, PA
XXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Sat, 23 Dec 1995 12:29:59 -0500
From: MSKoenig@aol.com
Subject: Re: Olfactory questions
The x test and one similar to the rope dragging are briefly discussed in
SCENT AND THE SCENTING DOG, WG Syrotuck.
The X test and similar ones are discussed in greater detail in OLFACTION AND
ODORS, William McCartney, Springer-Verlag, c. 1968. He also includes
references to the original studies, if you read German. The book may be out
of print, but Direct Book Service will try to find it for you.
Marcia Koenig
XXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Sun, 31 Dec 1995 13:27:54 EST
From: seibmyx8@ibmmail.com
Subject: Re: Olfactory questions
Morris Atwell (22 dec), Stephen Mett and Marcia Koenig (23 dec) discuss
tracks created by dragging an object by ropes.
This is also discussed in detail in 'Hunting by Scent' (Budgett, 1933).
I bought the book from an antiquarian bookseller in Wales. I have seen
it in some US book catalog (4-M Enterprises?). Budgett made many
experiments with preferrably bloodhounds. Among the experiments where
'dragged object'-tracks and advanced crosses.
Regards
Staffan Nordin
XXXXXXXXXXXXXXXXXXXXXX
Date: Mon, 1 Jan 1996 01:52:57 -0500
From: Snapstdx@aol.com
Subject: Re: Olfactory questions
In a message dated 95-12-31 19:06:14 EST, you write:
>
>Morris Atwell (22 dec), Stephen Mett and Marcia Koenig (23 dec) discuss
>tracks created by dragging an object by ropes.
>
>This is also discussed in detail in 'Hunting by Scent' (Budgett, 1933).
1933 was 63 years ago this date ( happy new year to everyone). I wonder if
the knowledge gained over the last 63 years, and changes in dog training,
would result in different results than Budgett's and the dog's he
experimented with. Syrotuck and Johnson, 72, 75, reported their findings
based on dogs 20+ years ago.
I am one who thinks that "some" dogs can be taught track direction.
Detecting scent direction is either a learned trait or an inherited trait.
Then again, an owner of dogs that go in the right direction are kept, those
that don't are ......
Twenty years ago it was believed that dogs could not follow a 3 hour old
scent on a nonvegetated surface and have been proven wrong. All dogs can not
do this, and all handlers can not do this, but it can be done.
IMHO
Richard Knapp
snapstdx@aol.com
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Mon, 1 Jan 1996 01:53:00 -0500
From: Snapstdx@aol.com
Subject: Olfactory/usefulness questions
Syrotuck quotes the amount of olfactory sensory cells inside the nose of
three different breeds.
GSD - 220 million
Dachshund - 125 million
Fox Terrier - 147 million
Humans - 5 million
I have to think and hope that investigation did not stop at these three
breeds and that there are some other statistics as respects other breeds and
their olfactory sensory cells. Can anyone tell me where I can get more
information on this subject?
Though this is a "Scent list", I hope we do not ignore the trainability,
usefulness, and practicality factors of various breeds with less than the
maximum olfactory cells as respects the jobs to be accomplished. A Golden
was the first bomb detection dog at the Statue of Liberty, not because this
dog had the best Olfactory senses for the job, but because of public relation
considerations. Beagles make great luggage searching dogs because of their
size and not just because of their olfactory senses. Pigs have better
olfactory senses than dogs (so I am told) but that does not make them
practicle and useful. Have heard that Mosquitoes have the best olfactory
senses LB for LB,, but would hate to try to put a collar on one, or ask Steve
Mett to carry a flock(?) of them in his patrol car :-)
I wonder if there is a list where we can HONESTLY talk about the best dogs
for the job.
Richard Knapp
snapstdx@aol,com
XXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Mon, 1 Jan 1996 17:18:18 -0500
From: Frank McNeil
Reply to: scent-l@txk9cop.metronet.com
To: Multiple.recipients.of.The.Scent.Training.List@metronet.com
Subject: Re: Olfactory/usefulness questions
Rchard:
I don't think that anyone is going to burn down your email address if you
state your opinion honestly; in fact, if you have an honest anything to
say, I believe that every person, ageny and group on this list would read
with great anticipation.
Obviously, from your message, you believe that there is a "best dog" for
the job (the "job" being whatever you choose to reference; police, SAR,
bomb, narc, urban, track, disaster, snow, trail, whatever.)
I DISAGREE. IN THE STRONGEST LANGUAGE ACCEPTABLE. Dog suitablility for a
particular task is based upon history, track record for the breed examined,
needs, public relations considerations, and human bias, to mention a few of
the possible criteria.
But, a BEST DOG? How do you determine that? My GSD is an excellent
air-scent dog, trails well, and is good on water. Does that make her the
BEST DOG? No.
There are several breeds suitable for SAR. I won't argue individual
virtues, because that is open to bias. I may be incorrect, but I get the
impression that you have strong ideas about what makes a breed or dog
acceptable.
Olfactory capabilities are not, and cannot be, the only criteria for a
scent dog (air or trail) - the dog must have a predisposition to working
for a handler (eager to please), a strong play drive (the main component
for maintaining interest in the job) and numerous other positive traits.
To select a dog based solely on breed is to set yourself up for
disappointment, as would be sole choice on olfactory capabilities, or size,
or color, or ears or...
The sum of the parts is greater than the whole, and the sum must be made
for each dog under consideration, as weighed against other dogs judged by
identical criteria. Exception must be made for specific function (I would
use a Bichon Frise for drugs, but not for winter SAR, for example; size is
a consideration in winter [snow]) and exclusion must be based on total
examination, not on single points of exam.
Honest discussion? Knock yourself out. I'll hear anything you have to say,
and my personal belief is that the vast majority of the people subscribing
to this list do so to exchange ideas, notions, and OPINIONS. You don't
have to agree with everything presented here, and I'd be amazed if you did.
Disclaimer: opinions and information offered herein are the sole
responsibility of the author, and do not necessarily reflect the policy of
the Connecticut Search Dogs personnel at large. No inference of
representation should be drawn, as none is offered.
Frank McNeil
Connecticut Search Dogs
P.O. Box 3461
Enfield, CT 06083-3461
fmcneil@connix.com
XXXXXXXXXXXXXX
Date: Tue, 02 Jan 1996 01:25:22 -0500
From: Stephen Mett
Subject: Re: Olfactory/usefulness questions
>Frank and Richard,
It seems to me that the information from Syrotuck should be taken as food for
thought and not as a qualifier or disqualifier for selecting a dog for
tracking.
The fact that a particular breed has a larger or smaller number of sensory
cells inside the nose is less important than picking a breed to fill a
specific need.
Frank McNeil points out that the intended appliation of the dog is most
important and I couldn't agree more. If you have a specific application in
mind, you will surely have boundries or restrictions that could limit the
breeds you could use. In such a case, the selection will be based on those
requirements rather than the Volume of Olfactory Sensory Cells.
For example: Using a Patrol Dog such as a German Shepherd for
Narcotics
detection in a crowded airport may not be the wisest choice. There
could be
a host of consideration that would make another breed a better
choice for this
application. That's not to say the German Shepherd is less qualified
as a
detection dog, but that another breed could reduce the risk of poor
public relations, potential bite situations or claim's of
intimidation by the suspect.
All valid considerations and ones that Police administrators
consider when assigning a dog to a particular work assignment.
Although the German Shepherd has a larger nose capacity (Volume of
Olfactory Sensory Cells) than a Begal or a Labrador
Retriever, the later may be the best choice for this situation.
>
As for the "Best Dog" idea, it has been my experience that there are good and
bad tracking dogs no matter what the breed of dog. I believe there are dogs
who have stronger natural abilities in tracking than others and if your
lucky to have such a dog, your job is that much easier. If not you
must be
dedicated and meticulous in your training approach. If you are open minded
to
various training techniques, select a technique that works best for your
dog, and
then train regularly, you can push any breed of dog to it's own individual
potential. (Key Words: Individual Potential).
Even the BloodHounds ability to follow old trails, may not be soley
dependant on the
volume of the Olfactory Sensory Cells. The BloodHound has been bread for
hundreds of
years to do mostly one thing. Track. So, has selective breeding played a
part in the
breeds abilities? Is the BloodHounds sense of smell more keen because he
has poor eyesight? Do his long floppy ears act as a funnel to help collect
scent as he follows a trail? And even if all of these factors do apply,
their are still varying abilities
within the Breed (the "Natural Ability" thing again). Just ask anyone who
has run BloodHounds on Game and could not break a dog from running back
tracks. This would suggest that one dog has superior ability over another
even in the BloodHound breed.
The botton line is you can teach any dog to track. But, the level of
performance achieved will likely be a combination of Natural Ability,
Training Techniques, and Handler ability, rather than just the volume of
Olfactory Sensory Cells.
Stephen Mett
Head Trainer
Orange County Sheriff's Office
Orlando Fl.
smett@magicnet.net
XXXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Tue, 02 Jan 1996 11:18:25 -0600
From: "Lawrence J. Myers"
Subject: Re: Olfactory/usefulness questions
Interesting discussion. And I'm impressed by the thoughtfulness of the
respondents.
If I can weigh in regarding the work on number of olfactory sensory cells in
various dog breeds.... There does not seem to be a statistically significant
difference between the sensory thresholds of beagles and GSD's for eugenol
or benzaldehyde, at least for those we've tested via behavioral and
electroencephalographic olfactometry.
There is work by others which is reviewed in the Handbook of Olfaction and
Gustation, R. Doty (ed.), 1995, Marcel Dekker, Inc., New York, ISBN
0-8247-9252-1 which indicates that a large portion of the olfactory sensory
epithelium (mucosa) can be lost prior to any detectable change in the
olfactory function. There's a lot more to sensitivity than just number of
receptors, so don't take as fact that GSD's are more sensitive than beagles.
I particularly liked the discussion of factors other than the sense of
smell. I found that I agreed with by far most of the discussion.
See, even a sensory physiologist agrees that sensory function isn't the
only, or even the controlling (providing that it's within some normal
range), factor in selection of a good dog for SAR or other detection work.
Lawrence Myers
Associate Director, Institute for Biological Detection Systems
410 Greene Annex
Auburn University, AL 36859-5532
(334) 844-4237
XXXXXXXXXXXXXXXx
Date: Tue, 2 Jan 1996 16:20:21 -0500 (EST)
From: Heather E Houlahan
Subject: Re: Olfaction and hormones
On Thu, 21 Dec 1995 SRLindsay@AOL.COM wrote:
>
> Dear Scent-L Subscribers,
>
> I have a number of questions regarding the effect of hormonal influences on
> olfactory performance. I would greatly appreciate comments together with
> references where applicable. But first a brief preface:
>
> Pietras and Moulton (1974) found evidence of olfactory acuity fluctuations
> occurring during the rat's estrous cycle. Further, the study revealed that
> estrogen activity tended to facilitate olfaction while progesterone tended
to
> depress it. Also, females injected with testosterone performed
significantly
> better than controls and better yet as the dose was increased. Further, the
> study found that male rats performed olfactory detection tasks at
> significantly better level than ovariectomized females. The authors
conclude
> that androgens play a significant role in facilitating olfaction in the rat.
>
What substances were our little rodent friends asked to detect? For what
incentive?
A working dog, trained for years to bring all of her drives and abilities
to focus on one kind of scent, in the face of innumerable distractions,
might have some different motivations than a lab rat sniffing camphor for
a food pellet (or to avoid a shock). The relative attractiveness of the
reinforcement can appear to have an effect upon the olfactory acuity.
> The above study raises a number of interesting and controversial questions.
>
> (1) What, if any, hormonal influences affect the dog's ability to smell?
> Further, what mechanisms mediate this effect?
>
A question I will let Ken handle.
> (2) Are there any significant effects on performance, reliability,
tenacity,
> etc. as the result of castration or spaying in the working dog?
There are old husbands' tales to this effect. I know of no one who has
worked with both altered and unaltered animals (their own!) who believes
there to be a negative effect. Having worked two female dogs who were
spayed as adults, I found no difference in performance, except that both
were consistently more focused and reliable when not in proestrus or
estrus. As spaying eliminated those periods (3x a year for both of mine,
for three weeks at a time -- i.e. nine weeks a year of effective down
time!), it had a net positive effect.
Male dogs are subject to unpredictable hormonal influences -- i.e.,
there's no telling _when_ they will be potentially distracted by a bitch
in heat. I have not worked a male myself, but by and large, handlers in
my old unit preferred, and seemed to have more success with, neutered
males. The only intact males with whom I worked closely (well, of the
_dogs_ anyway) were used regularly at stud, and seemed to be able to keep
a lid on it in the presence of females in estrus -- kind of like a
married guy vs. some pimply pubescent in the presence of cute girls.
>
> (3) Are there demonstrable olfactory differences between males and females?
> Do female dogs exhibit more or less olfactory reliability (detection
> thresholds) during their estrus cycle?
>
None that have been reliably, or even credibly, presented to me. A
popular author, Bruce Fogle, made the rather surprising assertion that
"Because male dogs use their sense of smell to scent out females in season,
they make better tracker dogs than bitches." (_Know Your Dog_ p. 47) No
attribution, citation, or substantiation for that little gem. (Christ,
_I_ can smell it when some bitches come in heat!)
I think it is unlikely that we could show gender differences in olfaction
based on actual work. There are too many other factors affecting
performance, and most of our working dogs, especially SAR dogs, are
working comfortably in the middle of their olfactory capabilities -- not
really stretching their noses. It's as if we were giving eye tests by
asking people to read a billboard at twenty paces. This is one for the
guys in the white coats and the little inbred beagles. And since both
sexes have shown themselves to be perfectly competent at every kind of
scent work, it is not a question that troubles me greatly.
> (4) Do corticosteroids affect olfactory performance? If so, what mechanism
> mediates the effect? Also, a related question, does stress impact on
> olfactory performance?
I seem to recall a discussion on this list sometime last spring on this
issue. Anyone? This is highly relevant to those of us who might have to
give our dogs steroids for skin or joint conditions.
I think that stress will knock out a working dog for other reasons before
it affects olfactory performance per se. It is reasonable to suppose
that mild stress (without fear) will moderately enhance olfactory
performance if only by increasing alertness.
>
> (5) Are all odorants equally detectable regardless of sex or are males
> better at detecting some smells and females better at detecting others?
>
d.o. question 3.
> Reference
>
> Pietras RJ, Moulton DG (1974). Hormonal influences on odor detection in
> rats: Changes associated with the estrous cycle, pseydopregnancy,
> ovariectomy, and administration of testosterone propionate. Physiol and
> Beh, 12:475-491.
> Thank you for considering the above questions and sharing your
> knowledge.
>
> Best regards,
>
> Steve
>
> Steve Lindsay
> Canine Behavior Services
> Philadelphia, PA
>
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Date: Wed, 3 Jan 1996 16:26:17 -0500 (EST)
From: Heather E Houlahan
Subject: Sigma Pseudo
My objection to using pseudo cadaver scent (for myself -- I _don't_
criticize others who choose to use it) is based on Sigma's unwillingness
to reveal any of the research and reasoning behind their choice of
chemical composition. I spoke to a couple of their chemists over two
years ago, and met with a blank wall -- they even refused to refer me to
any published literature on the topic of human scent composition.
Now, as a side note, at the time I had a job that involved, among other
duties, ordering supplies and equipment for a biological research lab. I
had freqent occasion to deal with Sigma in that capacity. When they were
selling supplies to research scientists, they were more than forthcoming
with all the specifics of each products' composition, prep. process, etc.
etc. -- any information that a researcher might want. But when I called
them from the same phone as a dog handler, inquiring about Pseudo -- and
in particular, how they could have different formulas for drowned victim,
regular cadaver, and "distressed" or "trauma" scent -- their attitude was
that Sigma knew best, and I didn't need to know. (Dog handlers don't
have PhD's, & so it's no use explaining anything to us...)
Well, I do need to know. I realize that Sigma Pseudo seems to be
effective in training dogs to alert on "the real thing." However,
without some insight into the reasoning behind its composition (I realize
that Sigma has the perfect right to keep their actual formula
proprietary), there is one thing I cannot evaluate: Will training to
this scent cause my dog to alert to some odor that is NOT human, in
addition to the real thing? In other words, could my dog give an alert
to, say, a dead cow or a drum of industrial chemicals because Sigma chose
a chemical composition that was too "generic," rather than being composed
of the chemicals that flag a cadaver as uniquely human?
It would take pretty exhaustive tests -- I would say that it would be
impossible -- to affirm that a dog trained to pseudo would not alert on
any other kind of dead animal, organic manufacturing waste, or random
chemical compound. This is hardly a trivial matter when a diver is
risking his life in a quarry, or when a disaster site must be dug out
based on a dog alert.
I am particulary concerned by Kathleen's observation that dogs trained on
real drugs will not alert to pseudo narcotic scent. This indicates to me
that Sigma may not have thought through the process of pseudo scent
composition very well. And I'm willing to bet that a nice, ripe human
corpse, with all the nifty chemical reactions and bacterial activity that
go on, is a lot more complicated and difficult to replicate than a
refined drug such as cocaine, or a dried and basically inert plant, such as
marijuana.
It's not easy to get the "real thing." But when I train with human
blood, hair, etc., or with "corpse soil," I at least know that whatever
makes it uniquely human is present, and have a reasonable confidence that
nothing else is.
My Mother's husband sliced off the better part of two fingers with his
snowblower a couple weeks ago, and would you believe that no one thought to
save them for the dogs!? I was hurt! And I'll never eat chicken fingers at
my Mom's house again. ;>
-- Heather Houlahan
Allegheny Mt. Rescue Group/Search Dogs Northeast
XXXXXXXXXXXXXXXXXXXX
Date: Wed, 3 Jan 1996 19:53:59 -0500
From: ARebmann@aol.com
Subject: Pseudo scents
mkhill asked about use of pseudo scents for cadaver search training. the
question appears periodically on the list. I have been training cadaver
search dogs since the late 1970's and originally did chemical imprinting
(prior to the availability of Pseudo) using substances that were difficult
and hazardous to handle.
Since 1990 I have trained over 150 K-9 teams from law enforcement and SAR
where the initial scent imprintation is done using Sigma products. During the
course of training the dogs are also exposed to actual samples, only to prove
to the handler that the dog will work on the "real" thing.
Before you begin working with pseudo scents, I would suggest you obtain a
copy of the training protocols from Sigma Chemical Company (1-800-521-8956).
They will assist you in introducing your dog to the source. Pseudo is an easy
to handle legal product. Actual human sources can pose some risk to the
handler and are illegal to possess in some states. Before attempting to
obtain actual sources, check both your states criminal code and public health
section of the state laws.
We can document many finds by dogs trained with the pseudo, both above
surface and buried. The dogs have located subjects from recently deceased to
documented criminal buried locations in excess of 20 years. In addition
pseduo trained dogs have been used on excavations of historical sites and
have indicated gravesites from colonial times.
If you build a solid foundation for scent detection, the dogs should have no
problems.
Andy Rebmann
K-9 Specialty Search Associates
Redmond, WA