Sun, Shade, and the Handler « Thread Started on Oct 26, 2009, 10:31am »
This time Murphy gets to be the source of a good lesson we should all keep in mind as we work our dogs. This last Saturday I handed a cavity wipe from a recent death to a problem setter to be used for Murphy's blind. I did this knowing that Murphy's weakest area is blood. I'm not too concerned with this limitation as most calls for HRD dogs come weeks, months, years, decades after the death and blood just isn't a concern. I'd much rather have a dog tuned to the subtle, minute scent sources than the loud source that an area search dog should (hopefully) find much quicker than an HRD dog. But, there are times when we might be called upon to perform such duties regardless of what's the best dog team for the job.
The morning was cold, so a frozen cavity wipe isn't a big deal. The problem setter was given a general area with the instruction that she'd tell me my dog's area when we were to work it. This is a semi-blind as I know there's only one source out there and what it is. The problem setter's dog is learning to do elevated, so with that in mind the source was to be at nose high to start the other dog off easily. The source was placed in a a small sumac tree in full sun next to dense woods with shade to the west, a road of gravel, dirt, and grass some 120 feet wide to the east bordered by more dense woods. There was a slope up from the road to the woods on either side. At ground level there was no perceptile wind. After the fact, it was noticed that there was approximately a 1 mph wind from west to east at the tops of the trees some 40-50 feet up. Total search area was not big, maybe 1.5 football fields long and 50 yards wide, or about 1.5 acres.
What the scent did in this situation. 1)Blood components diffuse very fast and spread far. 2) In full sun, air tends to rise and pulls the scent with it. 3) upper air currents can push scent along that should drop as it reaches colder air. So, in this situation, there was very little scent at nose high or below for the dogs to find near the source. With the air warmer in the sun than in the adjacent west woods, very little scent moved into those woods even though they were closer. There was a scent void on the ground until the east woods were reached and scent could drop.
Murphy got into scent in shaded region on the east side in an area approximately 80 feet north-to-south and 50 feet west-to-east. Sun bordered that area with breaks in the trees explaining the scent trap. Murphy exhibited scent behavior and told me twice that he had scent, but when asked to target would go back to searching. As a handler, I knew this meant he had scent with no source. The problem setter was instructed to give me no help unless I asked for it. As this was training and I didn't want to push my dog to commit to scent with no source, I finally stated/asked, "It's across the road to the west, in the sun, right?" The problem setter nodded. I should note that I've dealt with problems like this in the past, but normally some surface wind helps both handler and dog figure out what's going on. Only at this point did I start looking up and notice just barely perceptible leaf movement on the tops of the trees. If there had been no leaves on the trees, I probably wouldn't have had that to help me.
I pulled Murphy out of scent and asked him to go back to the west where we had been and I was (at the time) satisfied that there wasn't anything there. I don't dictate where my dog searches as I feel this suggests I know scent better than the dog. I do dictate areas to work. At this point, I was able to narrow the search area to a similar north-to-south area and have Murphy re-work the west tree line where he was able to locate the source. I visually located it by following his nose when we got a lucky puff of air movement and it pulled his head toward the source. (We handlers just feel so much better when we can get a visual confirmation. It should be considered a luxury rather than routine.)
I felt I should share my torture with this problem as it wasn't intentionally set up to be difficult. When the problem setter put it out, the source was in shade, but the darn sun just keeps moving. Every dog handler should always be aware of their dog's weaknesses and strive to work through them, being honest with others as to what needs to be achieved with problems. Going to training with the intention that your dog is going to impress all doesn't make you or your dog better at searching. Yea, it strokes your ego and it might fool the novices, but the victims or their families are the ones that pay the price. This sort of problem is exactly what a blind problem should be. The handler and the experienced dog should be given challenges that force them to work together to solve the scent problem, it should take longer than the typical 10 minutes in-and-out problem, and sometimes the handler will have to ask for help so as not to screw up their dog. There's no shame in this at training. There's no shame at a real search if you observe scent behavior with your dog that you don't understand and ask for another dog team (if one is available) to work the area with no prior knowledge of what you saw. Search work is not about competition, it is about improving ours and our dog's skill levels so the victim(s) can be found and pain resolved.
Many of the dog trainers out there now get caught up in their way is the only way of training dogs. Some of them do it because of monetary gain, some do it for ego, some do it out of fear that otherwise they might have been doing it wrong all this time (yea, some dog trainers are religious in their convictions, going on faith rather than successes and failures.....in HRD often times we never learn of our failures as the victims just go unfound.).
Most of my life I've learned so much more from failures than successes and the best place to fail is at training rather than on a real search.
Re: Sun, Shade, and the Handler « Reply #1 on Nov 7, 2009, 6:53pm »
Jim,
As you note, your dog is definitely trained differently than the typical HRD dog. From what I've seen, blood seems to be the easiest source for them to find and from great distances. Is it because blood is liquid that is diffuses so fast and far compare to our other more "solid" sources?
And while we're on the topic of blood, here's another question for you... Do you know if there is any difference in how blood from a wound through the skin, versus blood from a blood draw (just blood no preservatives), decompose? Someone somewhere was telling HRD handlers the two would have different scent pictures for a dog.
Your descriptions of training scenarios and how conditions affect scent are always educational. Keep them coming!
Re: Sun, Shade, and the Handler « Reply #2 on Nov 7, 2009, 10:43pm »
Joan, Here's a fun (well, fun for the person who sets up the problem anyway) blind to set up for other dogs with blood. Most teams when they train blood put it on or in something like a guaze pad or container. If you do have the advantage of a draw, then try this.
I usually start with semi-frozen blood because it's just easier to work with. Use 2-5 cc's. Find a tree that you know will be partially in the sun. If the tree has dark bark then so much the better. When I set this up, I like to place the blood where it will be in the sun, but a shaded side of the tree isn't that far away. Find a large branch, knot, protruberance on the tree and dump the semi-frozen blood on that location. If you can put it up out of sight, life is even better. The point of this problem is for the dog to target exactly where the blood is at. Lots of area search dogs can pick up blood. Targeting precisely is the hard part. Take away the visual from the handler where they are forced to depend on the dog and then you quickly learn how useful the dog team is. When I'm working with area search dogs, i.e. cross-trained, I tend to help them out when their nose goes up towards the source by a gentle verbal praise...sort of like a hot-cold game. If the dog teams can do this without help, by all means let them work this blind. I always adjust a problem for the dog and the handler's experience level. The point of the problem is not to torture, but to teach, but many problem setters forget that and just try to see how evil they can be. Real life tends to be the hardest task master. Oh, I tend to pick a place with lots of trees in the sun because the scent then rises and falls all over the place. The dog is forced to compare strengths of scent to determine where the source is. Having the dog going up the wrong tree on a real search will quickly give it a bad rep when it might just be inexperienced at judging scent strengths. This isn't something most cross-trained dogs are taught as the handlers and dogs are used to whole people sources that the handler eventually gets a visual reinforcement on. Forensic work often deals with locating clues rather than whole bodies and then recognizing something is a clue.
As Murphy is getting to work through this, I let him struggle and explained to another dog handler what was going on by his body postures, head turns, nose activity, etc. I do think that HRD and trailing dog handlers have to get very good at reading a dog through lots of avenues. We(the other handler and I) both knew where the source was as this was training, not a blind or test. The training was for Murphy. Once the dog knows the job, I believe in teaching by problem solving rather than cue and reward. Murphy gave me a bark when he was within three feet of the source. This happened very quickly. When I asked for "show me" then he had to really work to target as any dark bark in the area with sun and shade was causing the scent to rise, fall, collect in shade, etc. Murphy worked it out and did target precisely even though he could never quite reach the source. My goal today was to not allow him to dwell on scent traps, so someone watching me with him would probably think I was nagging him. I was basically forcing him to continually decide by putting a little mental pressure on him. Airedales actually like this type of handling, so it wouldn't apply to every dog. Some dogs you just stand back and let them work it out at their own pace. I wouldn't do this with a puppy, but consider it a valid technique with a dog confident in its skills.
You are spot on that blood diffuses much more than other sources. Now, if a dog team does most of their training on placentas (which are blood rich) then the dog becomes comfortable working in blood, but the handler still may not be requiring precise targeting. I personally in 11 plus years of HRD have never had to search for a woman having just given birth in the woods, so I tend to think that placenta work is over rated. Most of my searches are for water, clandestine graves, and scattered skeletal, so that's what I focus my dogs on. Probably the most frustrating search I can remember was where a well-funded tech group drove their 4-wheelers all over an area for hours and found two bones (driving over many others). The law enforcement agency then walked the area and found lots more bones and flagged them. I was then asked to come in and find more bones, but the bones(and flags) already there had to stay there until photographed the next day. The area was in a bowl and the bones all still had tissue on them, so the area was full of scent. In two hours we found five more bones and the body burn site. The L.E. agency was happy...oh yea, we found the scalp and hair as well. The remains had been spread out over an area pretty much the size of a football field by coyotes. The person had been missing 22 days in warm weather.
My point to this story is the dogs that do this type of work have to become comfortable in working throughout the scent pool to locate the sources. Scent cones just don't apply in these situations...oh yea, there was no wind. At that time I was working two dogs, alternating them. I traded them out every 30 minutes to cut down on frustration as this is highly mental work for the dog to figure out that I'm only mildly excited for them to target an already flagged bone/tissue source.
What would the difference be between blood draws and blood from wounds? The main difference would be in serum content and whole platelets. I've worked/trained on serum as well. Just takes having a centrifuge available. Now, since I've had the advantage of taking a blood spatter course, I'm thinking arterial spurt and a blood draw will create the same blood content. Most people when they think of blood don't consider the myriad of ways it can be placed. Cast-off from a weapon will create another blood scenario. I would recommend taking a blood spatter course if you can find one with law enforcement or a college forensic program.
Re: Sun, Shade, and the Handler « Reply #3 on Nov 12, 2009, 12:22pm »
Joan, I read the same article/opinion that you did. Let me introduce myself so you know where I am coming from. I have a MS in chemistry and biochemistry and I am currently a clinical lab scientist at a research hospital. I recently started HRD and I do not claim to know anything about training dogs. The first point I would like to make in reference to the article is that blood in the body does not contain bacteria. Any bacteria in the blood is abnormal. Blood is normally a sterile environment. Second, blood does not drastically change upon a wound occurring. In fact, if blood that has not clotted then the change would be insignificant. When some one is wounded thrombokinase is released from the damaged tissue and reacts with the prothrombin in the blood to for thrombin. Thrombin catalyzes fibrinogen which yields fibrin that covers the wound. As you can see, the component in the blood used to stop bleeding, plateletts and fibrin, is already in the blood except for the enzyme. Remember an enzyme speeds up a reaction. Clotting can take place without it but it will be very slow. Will this change the scent of blood? I think the change is insignificant especially when you consider that there are thousands of reactions that take place in a cell. If the tube is not inverted upon entering the tube there will be some clot form. Surprise! A needle stick in the arm is a wound! Generally speaking quite a large number of draws have at least some clot in them. When using drawn blood it may also be a good idea to use different color tubes if they are available. Jim's idea of working just the serum is a good idea. If you don't have a centrifuge and you have a tube without gel (red or lavender) you can just let it sit and it will separate pretty well. Just pipette off the top layer and use it. I would also suggest not freezing every tube you get. This seems to be standard protocol for HRD people. This causes hemolysis, which is breaking of the red blood cells. Also shaking the tubes vigorously will cause this. You can only really tell by the color of the serum once it is spun down.
Re: Sun, Shade, and the Handler « Reply #4 on Nov 12, 2009, 1:12pm »
This is not my line either but it is very interesting. I am in law enforcement and so do touch a little on the forensics end of it. But out on the street I sometimes have to have a blood draw on a suspect. In these draws we have an anticoagulant/ preservative that is added to the blood in the vile and then it can be kept refrigerated until it makes it to the lab. would that work to save blood and be used with the dogs in blood spatter work?
Re: Sun, Shade, and the Handler « Reply #5 on Nov 12, 2009, 7:19pm »
John, If your preservative is Sodium Floride then it would be better to just refridgerate the blood without any chemical preservative. My concern would be that we would train the dog on the chemical as well as the blood.
Freezing does cause damage to the blood, so if you wish to train fresh blood as if it just came from a wound then the blood bank's rule is 30 days in a fridge is all blood is good for. Shelly is an expert at what she does. I'm sure she could teach us all more about blood. I hope she does.
I'm embarrassed to say, but I've had vials of blood that were months old that I'd placed in an ammo box and forgotten (or someone gave me some). I tend to pour these into a hole in the dirt and use it once in a location where nature will dispose of it. I've done this at seminars as well and all the dogs trained on blood were able to target on it just fine which would lead me to think that (at least) some of the chemical components that dogs use to identify it as human blood were intact as there was no container and the dogs were not talked into the source.
Re: Sun, Shade, and the Handler « Reply #7 on Nov 13, 2009, 3:23am »
If you have a choice about what tube to have blood drawn in a red no gel is the best as it has no additives and will be drawn in a glass tube. This is usually what is drawn if it is a suspected DUI stop checking for ethanol or other volatiles. As Jim said, blood bank only keeps the blood for 30 days (a clinical lab will only test it up to 7 days if it has been refrigerated and depending on the test) because it begins to decompose and it causes significant clinical changes in the test results. Of course we will want to train on blood at different decomp stages just like we do tissue but you might want to keep this in mind if you are wanting to work "fresh" blood.
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