First of all, in scientific tests, dogs have proved themselves a million times more able than humans to sense certain smells. How is that possible? Its because a dog's nose has four times the volume of ours, and while a human nose contains about 5 million ethmoidal (olfactory) cells, Beagles noses have over 200 million.
Likewise, the outside of a dog's nose (especially hounds) is designed to pick up scents: large and wet, it collects and dissolves scent particles for easier identification. When a dog detects a desirable scent, it reacts by salivating, and the wet tongue also helps to pick up and dissolve more scent particles. Under perfect conditions, a Beagle can easily run a line by air scenting rather than sticking its nose down close to the ground. This type of running is often exhibited by Beagles from fast speed bloodlines used primarily for hare hunting/large pack field trials.
When a Beagler says that his or her hound is running a line, they are saying that it is following or tracking a scent trail that has been left by its intended quarry. Beagles can and have been trained to single out virtually any scent which makes them a very versatile hound. They have been used to track rabbits/hares, squirrels, deer, coyotes, foxes, raccoons, upland game birds -- also illegal drugs, bombs, natural gas leaks, combustible fuel evidence at arson scenes, and humans (search & rescue), just to name a few. Finding rabbits comes naturally to Beagles since this is what they were originally bred for. (Please note that each time I use the term rabbit, I am also talking about hares.)
Scent itself is made up of microscopic particles shed by rabbits and everything else on the planet. Since different objects have distinct chemical compositions, each also has a distinctive smell. A Beagle can even distinguish the difference between the scent of cottontail rabbit and the scent of a hare. If you could see scent, it might look like steam rising off everything in the field, each tendril of vapor intermingling with all the others. How is it that a dog can pick out one scent that matters out of all the smells in the outdoors? Its because they have super snouts that can distinguish between the most minute differences in scent and then they follow the scent they are trained and/or bred to track.
To further explain scent, we need to discuss scenting conditions as they are affected by different things. Just as we see better on a clear day than on a foggy one, Beagles can detect scent better under some weather conditions than others. Shade, moisture, and cool temperatures help to keep scent particles from drying out. A light breeze carries scent towards a hound that is downwind.
Dry air and heat evaporate scent and dry out a Beagle's nose. Rain washes scent away and extreme cold deadens it. Scent clings to soft, moist soil, and grass better than to hard, dry ground. Plowed ground and pavement are very poor holders of scent (pavement, apparently, is too smooth). Fog and mist make for good scenting, while cold, dry snow does not. Strong winds can scatter scent, and in the morning of a cold, frosty day, scenting conditions may be poor until the sun warms the earth somewhat.
A rabbit's activity, or lack of it, also bears on the ability of a dog to smell it. They definitely generate more scent when moving, which explains why dogs have a more difficult time finding the rabbits that sit tightly in their forms.
However, let me make something perfectly clear, just because a particular day seems to be a bad day for tracking, don't let that discourage you. Beagles get better and better at running the line the more they are allowed to practice. For example, our kennel is located in the Mojave Desert where the annual rainfall is less than 10 - 12 inches per year, yet our dogs can run a line with uncanny accuracy. This is because they run in this same environment day after day -- it tends to make them work harder and their noses get better at capturing the rabbit scent. I explain this phenomenon by comparing it to the extraordinary hearing of blind persons, once your sight is gone your body's capacity to hear gets more acute. Beagles that are run constantly during bad scenting conditions tend to develop more sensitive noses and then they can run in that type of environment when many other Beagles could not. So now that you do not have any more excuses, go run your Beagles in all types of weather and make them better all-weather hunters.
Scenting Rules For Rabbits
Rabbits emit scent from between the toes. Roads, other animals, including other rabbits, and humans can confuse scent. This is one of the reasons that judges at field trials ask the gallery (spectators) not to walk across a marked line that the Beagles have not run yet. As the rabbit tires the scent weakens (Beagles can sense this, and the seasoned hounds will often push up to the front of the pack). Pregnant rabbits carry little scent as a natural protection for both the mother and her future young.
Good Scenting Conditions
When the ground is wet
When the air is colder than the ground
When snow or frost is forthcoming
When the smoke from a garden fire or a chimney stays low and does not rise
When the hunted animal is running upwind
In the fog/mist
Vegetation after killing frost
Running Rabbits (when the game is moving)
When temperatures are 30-70 Degrees Fahrenheit (especially 30-40 Degrees Fahrenheit)
Bad Scenting Conditions
When the ground is dry
When the weather is stormy/unsettled
When the air is warmer than the ground
When the frost is coming out of the ground
When there is a strong wind
When there is heavy rain
Roads, concrete and hard, dry ground will not hold scent for long
Thick green vegetation
Sitting Rabbits (especially when the rabbits are sitting tightly)
Extreme Heat or Cold
These are the facts about scenting and tracking that I have learned from 30+ years of rabbit hunting and field trialing with Beagles. I have also found some of this information from reading scientific studies. If you are a Beagler and know of some more good tips or facts that I omitted, please e-mail them to me so that I can include them on this page for other Beaglers to read. Thank You!