Can You Really Evade a Bloodhound by Crossing a River?
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.
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!
Posted on August 14, 2011, in Characters, The Crime Scene and tagged bloodhound, Crime Scene, detective, fiction, forensics, man tracking, murder, mystery, police, thriller, tom adair. Bookmark the permalink. 18 Comments.