Can You Really Evade a Bloodhound by Crossing a River?

Bloodhound and Handler Working a Scent

The tracking prowess of Bloodhounds has been a staple of crime literature since 1890 when Sir Arthur Conan Doyle introduced “Toby” in The Sign of the Four.  In fact, from Doyle’s descriptions some might argue that the breed possesses almost magical ability to follow a scent trail. Well, if you define having over 4 billion olfactory receptor cells as being “magical” then I guess I’d agree. You see, the human body is constantly shedding millions of dead skin cells as we move around. These cells contain a unique scent that the dog can identify us by. It’s as if we are dropping radio isotopes and the bloodhound is a Geiger counter. Their over sized floppy ears and never ending supply of saliva maximize their ability to stir up and capture the cells from the ground as they track nose down to the ground.

Bloodhounds have been bred to track and I have watched them find evidence when no other breed could. Over my career I’ve had the good fortune to work with several outstanding dogs and handlers who have literally tracked criminals to their front door step. They have tracked moving vehicles for dozens of miles, found bodies under water, and even grave sites in flood ravaged areas. A well-trained dog and handler and an invaluable asset to a law enforcement agency.

But if you watch enough television you might think that this amazing animal has an Achille’s heel. If you’re a bad guy being chased by bloodhounds all you have to do is cross a river and you’re home free right? Wrong. I’m not sure how this idea came to be so common. Perhaps as authors we simply can’t fathom a Superman without a Kryptonite. Every great character has to have some fallibility otherwise they seem too good to be true right? Whatever the reason, the idea that crossing a river ends the chase is simply not true.

In the movies it’s always a small river too; never the Mississippi. Imagine a group of rough and tough lawmen chasing a murderer when to their shock and horror the trail ends at a small river bank.   “Weeeeell shucks! That son-of-a-gun crossed through this knee deep water! He’s gone for sure now. Let’s call it a night and head to Dunkin’ Donuts”. God help us all if law enforcement ever gets to that point.

The fact of the matter is that bloodhounds can track a scent over water. It’s true that the moving water will carry a scent down-stream but this is only an issue if the bad guy is moving upstream (away from the scent). Coupled with that is the fact that even if a bad guy wanted to travel through a river there are several things that work to his or her disadvantage.  As any fly fisherman will attest; walking along a stream bed is tricky. The rocky bottom is uneven and slippery; and then there’s the current. In places like Colorado the water can be just above freezing even in the Summer at some elevations! The fact of the matter is that you slow your speed of escape tremendously in water and this is not what the bad guy wants. Sooner or later they have to get out and onto dry land again.

Bloodhound in a Boat on a Lake Search

This is why a good bloodhound handler simply works the banks. In all likelihood the suspect will leave signs of disturbance like shoe impressions or damaged vegetation that even a rookie could find. If by some chance he gets out on some rocks the bad guy is still shedding skin cells and a well-trained bloodhound will quickly recover the scent. In a way, I suppose we should encourage all criminals to wade into rivers if for no other reason than to slow down their escape. But if you’re planning on using this scenario in a novel just be aware that it doesn’t work well unless you’re cops are jonesin for a doughnut fix!

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About forensics4fiction

Hi there. Thank you for visiting my BLOG for crime writers. I hope you will find it interesting. I would love to hear your questions and thoughts regarding forensics and criminal investigations. I hope that the information here will help answer your questions or ignite your imagination. I am a retired senior criminalist with 15 years of forensic experience. I have served as the president of the Association for Crime Scene Reconstruction, Rocky Mountain Association of Bloodstain Pattern Analysts, and the Rocky Mountain Division of the International Association for Identification. I am triple board certified in forensic related fields and one of only 40 board-certified bloodstain pattern analysts and 80 board-certified footwear examiners worldwide In addition to writing over 60 scientific papers, I have worked as the editor of the Journal of the Association for Crime Scene Reconstruction, been interviewed by and consulted for television, books, magazines, and newspaper articles including documentaries on the Discovery Channel and National Geographic.

Posted on August 14, 2011, in Characters, The Crime Scene and tagged , , , , , , , , , , . Bookmark the permalink. 18 Comments.

  1. Another great article! I always learn the most fascinating things from your posts.

  2. Thank you so much Abbie, feel free to ask questions if an article spurs a plot idea or something.

  3. Hi Tom! Great article I might have to work this into the next story, well not the river thing but the hound thing. I know all hounds have an inherit ability to track, do you know what kind of specialized training techniques they have for forensics? Is it like you see in the movies, smell the guys shirt of the drugs and go get ‘em boy?

    Thanks a bunch. Michelle

  4. You cleared that up. Fascinating. Thanks.

  5. Thanks Michelle, the world of dog training is very interesting. I keep telling myself to write a series of articles entitled “Bad Blood” about the advesarial relationship of tracking dogs in LE. Basically, most agencies use a working breed like Shepherd or Malanois to do both man tracking and more aggressive tasks such as crowd control, clearing buildings, and arrest control of combative suspects. You can imagine that a bloodhound wouldn’t be very intimidating to a suspect with a gun or knife (or wiffle bat for that matter). Because of this bloodhounds are not common and handlers are sometimes looked down upon within the agencies. Coupled with that the rise in what European LE’s have introduced as “disturbance tracking” which is a theory that the dog can search by a combination of scent and visual indicators of disturbance like bent blades of grass. I wont get into my thoughts on that here suffice it to say that I have worked with many breeds of dogs in LE and I have yet to see a sheperd or malanois track more than 20-30 yards convincingly whereas I’ve followed bloodhounds for blocks and miles along tracks that have been confirmed from other sources like surveillance footage or eye-witness accounts not known to the handler.
    As for technique your understanding is basically correct. There is a big difference between tracking a living person and a dead one. Dogs can be trained to search for both and some handlers use different collars or leads (leashes) to indicate to the dog what they are expected to track. But when searching for a living subject they will use some kind of scent article like a piece of clothing to tell the dog what scent they are looking for. Care must be taken to use an article that primarily has the suspect scent adn hasn’t been contaminated by others. I’ve used large patches of gauze that I have swabbed areas the suspect touched like a body or steering wheel to scent the dog on. Of course, the handler will walk the dog past all of the CSI and first responders so the dog knows to eliminate those scents from consideration (I don’t want him tracking back to my house!).
    I will make a note to do some more articles on how bloodhounds have been used effectively including vehicle line-ups (which are really cool).

  6. You also asked about training techniques…sorry I got off on a tangent. Training can take many forms but you can imagine that it is pretty easy to tell if your dog and handler are working well together. I should mention that a good handler takes a lot into consideration when selecting a puppy for training. To say that every bloodhound would make a good adn reliable tracker is inaccurate. Dogs, like people, have a variety of temperments and aptitudes and while the breed has exceptional sense of smell the individual dog may not be suited for police work. I can write more on that in a posting. But, once the handler and dog are working together traning can be pretty straighforward. One test is to have an unknown person walk or run across several different surfaces (grass, concrete, dirt, etc) that other people have also traversed. The identity and path of the subject are unknown to the handler and dog but known to those administrating the training. Then the dog is scneted off of a scent article (like piece of clothing) and the tracking begins. Since the instructor knows the exact path of the subject they can evaluate how well the dog/handler team does on the track. If the dog veers off at some point the handler needs to figure out why. It may be that there was something that interested the dog like a dead animal. The dog may know what track he/she is on but when corrected (A good handler can tell when their dog is getting off track) looks back at the handler as if to say “Look, I know where I’m going but there’s something over here I want to check out first so keep your powder dry for a minute while I check it out. Once I’m done over here I’ll get back to your stuff”. If you’ve ever been around any trained dogs they can exhibit this behavior. People get frustrated and wonder why the dog’s training supposedly went to hell when in actuality they are just expressing individuality. Trainers don’t like it but it’s a fact of life.
    When training for finding dead bodies hgandler can use things like teeth or medical waste and they will hide it somewhere in the training area and work the dog to find it. They also use actual death scenes for training as well. Say you have a person who committed suicide in a field or something. After the body is long gone the handler might enter on one side of the field and have the dog work it to see if the dog locates the spot where the dead body was.

  7. The TV show, MYTHBUSTERS, has done a number of segments on the various ways a criminal can supposedly avoid being tracked by a bloodhound. Each method was tested against bloodhounds with professional trainers, and I don’t recall a single instance when the dog was confused by a trick to hide the scent.

    Probably the most remarkable evidence I’ve seen of the power of a dog’s nose was two cadaver dogs who were brought in separately with different handlers into a B&B room where a woman had been killed and wasn’t discovered for several days. Both dogs found the scent exactly where the body was found.

    What is remarkable is the crime was almost a hundred years old, and the room had gone through an incredible number of cleanings and several remodelings since as well as being occupied by many people.

  8. Absolutely fascinating! Thanks Tom for all your insight and knowledge.

    One more question – are the handlers professional associates that contract with the police? Or are they actual police officers? Or are they raised and trained by one person and then handed off to law enforcement when trained?

  9. Most medium to large sized agencies have their own handlers and dogs (as officers or deputies). In some case they may contract a search and rescue team which can pose a lot of problems for clandestine grave searches. There have been a few high profile cases of SAR handlers with questionable findings and one even planting evidence! Most of the time if there is an outside handler brought in it is to track a non-violent offender or to search for a dead body. Dogs have physical limitations and searches may take days so dogs can use the help and rest. Most handlers won’t run their dogs all day long especially in the heat. They have to have a break. That’s when the support dog takes over. When searching multiple locations or very large areas multiple dogs may be used then as well.

  10. I’ve seen dogs hit on 120+ unmarked graves which is pretty impressive as well. Great info on the Mythbusters program. I’ve never watched that show but it looks like those guys have a fun job!

  11. In the Sunny South

    Interesting post!! Thanks!

    I wonder why too many seem to be using labs. As one who lives altogether too near one I can attest that they seem too stupid to use for anything except to annoy the world (even their dumb owners once they got a life) and yet that seems to be the type dog used in my area. I’d love to hear your take on that as I want to remark on them in a novel & compare their stupidity to intelligent dogs like bloodhounds.

  12. As a very proud lab owner I respectfully disagree. All dogs have great capacity for learning; it’s the trainer that usually doesn’t get them to their full potential. You raise an important question, however, as to why many departments use certain breeds and not others. Unfortunately, it typically boils down to logistics and economics. While bloodhounds are the best tracking dogs in my opinion they aren’t much good for any other law enforcemernt duty and they can outweight a lab by 50-100 lbs (requiring more food). Agencies like Shephards because they can do crowd control, building searches, and tracking (even if not as well). It’s one dog doing multiple jobs. Likewise, a labrador can be trained to search for drugs, explosives, arson evidence and the cost is much lower. They are also easier to handle. Another issue is that most canine units are part of patrol. Patrol operations are very demanding. If I had my way the bloodhound would be a part of the investigations division but that goes against the grain of modern law enforcement culture (kingdoms) and is unlikely to become a widespread reality.

  13. My untrained bloodhound is 28″ and weighs 120lbs. She is a big one. She can track anyone just by smelling an article of clothes. That is what they do. The training part deals with reading the dog and keeping the dog focused. We cannot keep up with her, so we just play around in the fenced acre we have. She will cross track on her own. The cross tracking means that they will come to a circle back trail and turn to follow the freshest scent. Even if it is only fresher by a few minutes. She can also pick up scent in the air and will turn in that direction and then pick up the ground scent again. They do not back-track, but maybe they could be trained to do so. I don’t know. It is fun to just watch her track my husband or a friend. When we were camping last summer my husband and I both had to go up to the bathhouse. He went ahead while I waited a few minutes. We were going to change off on the dog. When I headed out with her on the road, she picked up his scent (on her own) and followed it directly (through the grass and not the road) to the mens room and just went on in. Fortunately she was on a really long leash!!!

  14. I forgot to mention that she is pretty much useless for anything else. A guard dog she isn’t. Her size might intimidate someone, but to sic her on someone will only get them licked!

  15. I have a question for you.A man came to my door with a gun held to me the police dog tracked his scent and then lost it at the river.So is it only blood hounds that can track them even if they went through the water? In this case I don’t believe the police did enough to try and pick up the scent on the other side of the river,and I’m sorry but I was so upset I don’t know if this dog was a blood hound or not.Thank you for your help with my question.Have a great day.Dolores Colorado

  16. How scary for you Vickie, I hope you weren’t hurt. I don’t think it would be fair to say in most cases that they weren’t trying hard to pick up the scent again. I don’t know about your case but dog handlers and dogs WANT to track, it is what motivates them. Water can really impeded the sloughing of skin cells which is what the dogs are tracking. Of course, there is always the issue of training for both the dog and the handler (I’m assuming they were law enforcement as opposed to some local search and rescue team) and that can contribute to the success of a search as well. Other considerations are the weather and the quality of the scent article they are using for the track. Tracking is not as simple as turning a dog loose and sometimes they come up short. In my opinion, well trained Bloodhounds are the very best tracking dogs but they can lose a scent for a variety of reasons. I have seen other popular law enforcement breeds like Shepards lose a track after a few yards so if you had a bloodhound up there the odds were in your favor.

  17. This has been fascinating, thank you so much. I am pretty unsophisticated with blogs so I hope you see this even though the original post is rather old.

    In my story line a young man runs, not necessarily from the law but as far from home as he can get. He is bleeding and heads to an empty barn, perhaps going through the creek, but if so by necessity, not to hide his scent. The whole thing takes place nearly a century ago in a rural area. No bloodhounds available, but likely hunting dogs. Is it possible for a family member to divert the dogs, perhaps at the creek, by using something with the young man’s scent to lead them up a trail to a road? Once the young man realizes he has to try to hide his scent, is there anything simple he could do, or someone else could do for him, again assuming the dogs are not trained for this?


  18. Dogs were used for tracking in the early 20th C but not all for man-tracking. Most trackers were a bit more adept at following sign however and if the area is rural then most investigators would think to check all local properties (barns) since there wouldn’t be that many. The best way to hide his trail is to stop the bleeding and move through rough terrain. Additionally, in schools of escape and evasion the main objective is not to get caught. If he can keep some distance between himself and pursuers then it doesn’t really matter if they can follow his trail some distance. Sooner or later the trail goes cold. Bad weather, bad terrain, tired dogs, crossing other pedestrian trails, etc all conspire to hamper a track. Also, if the track gets weak (little sign) there could be infighting among trackers to try alternative trails thereby splitting up the teams. All of this may help your character avoid detection. I hope that helps.


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