Dogs are extremelly important in our society. They provide love to many and also help us with other tasks such as: guide dogs for the blind, explosive detection, drug finding, people search after earthquakes or avalanches, and they can also be great hunters. Moreover, they are useful in less transcendent but very interesting tasks like truffle search (used to be done with pigs, but dogs have the advantage that they don´t eat them).
Many of these tasks are related to the exceptional sense of smell that dogs possess.
Effectively, dogs can smell way better than we can. They are much better equipped for it.
Their ability to smell is due to a layer of specialized cells in the nasal cavity. A dog has the nasal epithelium 30 times more developed than humans, so they are able to perceive the presence of an odor at concentrations ranging from a thousand to a hundred times lower than we can.
People have around 0.46 in2 of olfactory epithelium, while some dogs like the Beagle reaches up to 12 in2. Besides, if that wasn´t enough, they have a greater proportion of nerves that will take the information received by the nasal epithelium to the brain. Us humans, we have 5 million olfactory receptors, while a dog can reach up to 220 million. Finally, a dog’s brain has a much larger portion devoted to decipher odors, much larger than ours. In fact, dogs perceive the world thanks to their sense of smell. A dog is more helpless if it loses its smell rather than its vision.
Areas devoted to smelling in a dog (left) and in humans (right)
We have seen multiple uses that the exceptional smell of dogs can have for us, but there are new benefits less known but that are still very intersting:
The ability that dogs have to smell prostate cancer. When confronted with several urine samples some dogs can distiguish those that belong to a person with this disease. This use is limited, but in some cases, trained dogs were able to detect tumors not yet diagnosed by other means.
In recent studies, samples of exhaled air by patients with breast or lung cancer were used; dogs detected the positives in a range between 88% and 100% of the cases. These studies are being developed now to diagnose ovarian cancer. We will discuss this topic in more detail a little later.
Here is the advice given by the doctor responsible for these tests: if your dog smells a part of your body consistently and it´s a new type of behavior…maybe it´s trying to tell you something.
As we have seen, they are able to detect drugs, explosives and even legal bank notes. But their abilities go beyond, let´s look at other possibilities:
- Detect illnesses that affect beehives. Specifically American foulbrood. Since for beekeepers it is very important to identify and treat the infected colonies, dogs are trained to detect infected hives way early so beekeepers are able to apply the treatment sooner and avoid the death of the hive.
Hive affected by American foulbrood. Dogs can detect the disease before it develops, helping farmers to take preventative measures.
- Smell the material DVD´s are made of. The illegal commerce of DVD´s is very extended, especially in Asia, so police from those countries train dogs to be able to detect polycarbonate, one of the materials used to create these fake discs.
- To find whale poo. Although it seems incredible, there are some people interested in these remains: scientists. This way they can figure out the diet of these cetaceans and evaluate their health. The problem is that the excrements of these animals sink 30 minutes after being evacuated. Because of this, dogs are very useful in order to find them before they submerge forever.
- Diabetes: like we have explained previously with some types of cancer, there are some dogs that are able to smell diabetes. They specifically detect when a person is going to have a hypoglycemic crisis.
- Bedbugs: these annoying parasites are still present in many places. They are very hard to see and to fight. And when they get strong in a hotel they are able to ruin an entire business. Due to this, dogs have been trained to be able to detect them. And are able to do it with precision: up to a 96%.
Dog specialized in detecting bedbugs
- Bodies of people drowned and submerged: United States of America police have trained dogs for this: to find submerged corpses. People that have drowned and whose body can only be found by dogs that are able to detect the smell of a decomposing body even in places with strong currents. They are able to detect corpses up to 30 meters below the surface.
- And if all this wasn´t enough, dogs can also be trained to find snails. But no, not to make delights of the most refined gourmet but as in part of a plan to eliminate invasive species. Specifically, a giant specie (can reach up to 20cms) of a terrestrial African snail which has been present in the South of the United States and has even reached the biggest of the Galapagos island. This mollusk eats the crops in an avid search for calcium for its shells. Since it doesn´t have enemies outside of its natural habitat, it proliferates uncontrollably. For this problem dogs represent, with their magnificent smell, a solution since they are able to detect both adults and their eggs and thus enable their eradication.
In the Galapagos Islands, dogs are trained to find snail invasive species
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