Can a Dog Smell Through Water?

Dogs are well-known for their superior sense of smell. They have evolved with an olfactory system that makes them highly proficient at tracking scents; this not only helps them to be efficient hunters, but they can be trained to assist humans with a range of tasks that require a sensitive nose.

Dogs are so well-attuned to smell that they track specific scents through different materials, including water. This makes dogs extremely useful in an investigative context, particularly when searching for missing people. In this article, we’ll explore the amazing abilities of canines to identify substances, even in challenging circumstances. 

When a dog can smell something through water, they will display behavior consistent with the discovery of anything interesting. Firstly, they will become very focused on a particular area, with signs of alertness. Their ears will be raised, and they will most likely be wagging their tail. If the dog is swimming in water containing a sample of a substance they are interested in, they will circle the area containing the substance, or return to it frequently.

A dog will also alert an owner or handler to their discovery. If they are trained to seek out specific substances, the dog will display a set behaviour; usually sitting, laying down, or stopping at the location of the substance. They may also provide an audio cue if instructed to do so, although this would usually be reserved for instances in which a dog is in the water.

Dogs that are not trained to detect specific substances will also encounter scents that interest them. As well as showing signs of alertness, they may growl, whine, or bark, and they will almost always try to grab your attention. This may involve jumping up, pawing, or leading you to the location of the smell.

Some breeds are naturally more attuned to smells, particularly Bloodhounds, Beagles, Basset Hounds, and German Shepherds. They tend to make effective police and security dogs, especially in complex situations, including detection of scents through water.

Dogs have always had an aptitude for the discovery of substances and objects contained within different materials. This had made them useful assistants in law enforcement and criminal investigations. In fact, the reputation of dogs was so strong that Bloodhounds were used by London’s Metropolitan Police during the hunt for Jack the Ripper. Although that particular criminal was not reprimanded, the idea that dogs could assist with specific aspects of an investigation began to catch on.

At the turn of the 20^th century, innovative approaches were developed in France, Belgium, Austria, and Germany to utilise the natural abilities of dogs, particularly German Shepherds, in the identification and reprimand of criminals.

Canine support soon became a feature of modern policing; techniques were refined to train dogs to identify specific scents and respond to commands and aggressive behaviours. Dogs are now used to help in search and rescue operations, to reprimand criminals on foot, to support security operations, to assist military personnel, to detect explosives, and to identify drugs or other illegal substances. Working dogs can be found routinely at airports, public events, mail sorting centres, military bases, and security points.  

The canine sense of smell is highly developed. In dogs, there are 300 million olfactory receptors in and around the nose; in comparison, humans have just 6 million! The part of the brain responsible for interpreting smells is also 40 times more powerful in dogs than it is in humans. 

The physiology of the canine respiratory system is also precisely tuned for the analysis of scent. Humans have one route from the nose, which serves a dual purpose; to breath and to smell. In dogs, there is a separation. From the nose, one route serves the delivery of air to the lungs, and the other goes to the smell receptors. The brain and olfactory receptors work together to analyse the content of the air, and constantly make connections based on previous experiences.

A dog’s olfactory system is so powerful that they have the ability to identify one tablespoon of sugar within a million gallons of water! This explains their capacity to discover small amounts of contraband concealed within a more compact vessel, or indeed their effectiveness during search and rescue efforts, particularly those involving large amounts of water.

The professional training of dogs to assist in law enforcement, search and rescue, or security, can be a long and complex process. It starts with selecting the most effective breed for the task. German Shepherds are useful in a diverse range of applications, as are Beagles, Basset Hounds, and Labradors. Bloodhounds tend to be used for search and rescue, or to specifically look for cadavers.

Once a suitable puppy has been identified, the first step is training them to be highly obedient. Specialist handlers will teach them a range of voice commands and gestures, using positive reinforcement to reward success. Dogs that are difficult to control at this stage are unlikely to move forward in their training.

It is essential that any dogs engaging in support work have the physical and mental capabilities to perform them. Dogs must be agile and fit, with no prohibitive physical ailments. They must also be confident, with the ability to work in busy and intimidating environments. Once a handler is satisfied that a dog has fundamental skills in place, they will be ready to focus on specialist training.

If a dog will be deployed to sniff out drugs, they will learn how to identify illegal substances using play. A clean towel is introduced to the dog, and used for several fun games of tug-of-war. The illegal substance is then bagged and rolled in the towel, which is used again for playtime. The dog begins to associate a particular smell with the towel, and so with the concept of play. When the substance is detected in a different context, the dog will respond as if it is time to play, which helps law enforcement officers to identify criminal activity.

A similar process is used with other substances, including explosive compounds and chemicals that indicate the presence of cadavers. Dogs will be trained to perform only one type of search, as it is not possible for them to communicate to their handler which substance they detect.