Dogs have an extraordinary sense of smell, but olfactory ability alone does not determine how effectively they perform scent detection tasks. A dog may be capable of detecting an odour but have little motivation to search for it, or be highly motivated to search but struggle to maintain an effective strategy when the task becomes difficult.

Professional detection work requires dogs to search in complex environments, sustain their attention when targets are difficult to find, adapt to changing conditions, and communicate their findings to a human handler. The dog may need to work for extended periods without finding anything, while remaining responsive to the handler and unaffected by much of what is happening around it.

Research into detection dogs has therefore examined a range of behavioural characteristics beyond olfactory sensitivity, including the propensity to hunt, reward motivation, task engagement, persistence, adaptability, independence, cooperation, and environmental resilience.

These characteristics overlap, and their relative importance varies according to the type of detection work. Research also approaches them from different directions: some studies ask experienced handlers what they look for in a dog, while others use behavioural assessments to investigate which characteristics predict later working outcomes.

This article reviews six papers published between 2017 and 2026, examining what these characteristics mean, how they interact, and what the evidence tells us about their importance.

1. A good nose is not enough: olfactory ability, scent orientation and the propensity to hunt

Olfactory ability is an obvious requirement for scent detection work, but there is an important difference between a dog’s sensory capacity and its tendency to use that capacity.

Lazarowski and colleagues (2020), in their review of behavioural characteristics associated with explosives detection, distinguish between olfactory sensitivity and odour-guided behaviour. The latter concerns how a dog uses scent information to investigate its surroundings, identify a target odour, and locate its source.

One characteristic associated with this behaviour is the propensity to hunt, sometimes described as hunt drive. In detection work, this refers to a dog’s motivation to engage in olfactory searching. Although the terminology originates in hunting behaviour, the relevant characteristic is the willingness to investigate and locate odours, rather than necessarily pursuing or catching prey.

Some dogs engage in extensive scent-based investigation spontaneously, without being specifically trained to do so. Lazarowski and colleagues suggest that, for these dogs, searching may be intrinsically reinforcing: performing the behaviour is itself rewarding.

The closely related concept of scent orientation describes a dog’s preference for searching using olfactory rather than visual information. In a 2026 study from Utrecht University, Roulaux and colleagues interviewed professional scent detection dog handlers and trainers about the characteristics of their ideal working dog. Scent orientation was among the characteristics they considered particularly important and were least willing to compromise on.

This preference has practical implications. A dog that is strongly motivated to investigate odours may require less encouragement to begin searching and may remain engaged even when the probability of locating a target is low. However, a preference for olfactory investigation does not tell us everything about how the dog searches.

Search technique and precision

Dogs can use different strategies to locate an odour, depending on the target, the environment and the information available.

Air scenting involves sampling odour carried in air currents and using that information to locate its source. Dogs may also investigate close to the ground or individual objects, concentrating their sampling in particular locations. Lazarowski et al. (2020) describe these behaviours as a continuum rather than completely separate techniques. Even when a dog investigates the ground, it is sampling airborne odour molecules. The distinction concerns where the dog directs its attention and how it uses the available scent information.

Different tasks favour different approaches. A dog searching for airborne odour associated with a moving person faces a different problem from one locating a small, concealed source in a building. A dog may also need to change its sampling behaviour as it moves from detecting the general presence of an odour to identifying its precise source.

Search precision is partly trainable. In the Utrecht study, professional handlers were more willing than recreational scentwork handlers to accept lower initial precision. Some explained that they could develop more precise searching by training dogs to locate increasingly small odour samples, encouraging them to investigate more carefully.

This distinction matters when selecting dogs: the tendency to investigate odours may be a fundamental characteristic, while aspects of the dog’s search technique can be developed through experience and training.

2. Why dogs keep searching: motivation, reinforcement and task engagement

A dog’s willingness to begin searching is only part of what makes it useful in detection work. Many searches involve substantial periods without a find, and the dog needs to maintain its engagement despite receiving little immediate reinforcement. Understanding what motivates the dog is therefore important.

Intrinsic motivation and reward value

When a behaviour is intrinsically reinforcing, performing it provides a rewarding experience. In the context of scentwork, the opportunity to investigate and search may itself motivate continued activity.

Detection training also relies on external reinforcement. Dogs are typically rewarded for locating a target or performing a trained response, often through food, toys or play. These sources of motivation can interact.

Lazarowski et al. (2020) explain that dogs with a strong intrinsic propensity to hunt may remain engaged for longer periods when opportunities for external reinforcement are infrequent. The dog continues searching because the activity has reinforcing value, while learned associations with rewards help maintain the specific detection behaviour required by the handler.

Different rewards also have different values for individual dogs. Food can be highly effective, although its reinforcing value may decrease with satiety. For other dogs, the opportunity to chase, retrieve, possess or play with an object can provide particularly strong reinforcement.

Even the way a dog responds to a reward can be misleading if interpreted in isolation. A dog that readily releases a toy after a find might appear less motivated by the reward than a dog that refuses to surrender it. However, Lazarowski and colleagues describe how a dog with strong hunting motivation may relinquish the reward because returning to the search is more valuable.

Measures of object possession can also reflect different underlying motivations. A dog may maintain its grip during a tug game because it values possession of the object, because it enjoys interacting with the handler, or through a combination of the two.

Consequently, motivation cannot always be inferred from a single behaviour, particularly when that behaviour can produce several different rewarding consequences.

Task engagement and search focus

Motivation to search is closely related to task engagement, but the two concepts are not identical. Task engagement concerns the dog’s ability and willingness to remain involved in the search without frequent encouragement or guidance from the handler. A dog may begin enthusiastically but repeatedly interrupt its searching to investigate unrelated stimuli, seek direction, or disengage from the task.

Lazarowski et al. (2020) discuss a construct called search focus, which combines several observable behaviours: sustained olfactory investigation, limited distraction, independence from handler input, and sufficient physical stamina to continue searching. These characteristics are particularly relevant when targets are difficult to locate or when the dog has to search a large area.

Distractibility, however, is not necessarily a single characteristic. A dog may become distracted because it is attracted to something else, concerned about an unfamiliar stimulus, insufficiently motivated by the search, or experiencing difficulty maintaining attention. Identifying what interrupts the dog’s searching can therefore be more informative than simply describing it as distractible.

It is also worth distinguishing sustained engagement from intense physical activity. A dog can remain methodically engaged without searching frantically or moving continuously at high speed. The relevant question is whether its behaviour continues to contribute to locating the target.

3. What happens when searching becomes difficult: persistence, flexibility and frustration

Many detection tasks require dogs to continue working when their initial attempts are unsuccessful. A target may be difficult to locate, an odour may become temporarily unavailable, or the environment may prevent the dog from reaching its source directly.

Persistence is therefore frequently identified as an important working characteristic. In the Utrecht study, professional handlers defined persistence as persevering despite setbacks and obstacles. It was among the characteristics on which they were least willing to compromise.

Similarly, Salamon and colleagues (2026), surveying explosives detection professionals in four European countries, found persistence among the most highly valued characteristics, alongside olfactory ability, willingness to work and motivation for reward. Yet persistence can take different forms.

Persistence is not the same as behavioural flexibility

A dog may persist by repeating the same behaviour despite repeated failure, or by continuing to work towards a goal while trying different approaches. Both involve persistence, but the second also demonstrates behavioural flexibility.

This distinction is important because a behaviour that is useful in one situation may become ineffective when circumstances change. A dog that continues following an unproductive search route may remain highly motivated but fail to use information indicating that a different approach is needed.

Behavioural flexibility allows the dog to modify its behaviour in response to changing conditions while maintaining its overall goal. Lazarowski et al. (2020) discuss evidence that high persistence can sometimes be associated with difficulty adapting to changed reinforcement conditions. One study they review found that greater persistence during extinction was associated with poorer olfactory discrimination learning.

Other studies have examined how dogs respond to unsolvable tasks, such as attempting to retrieve a reward from a closed container. In these situations, continued independent attempts do not necessarily indicate more effective problem-solving, particularly when the dog cannot succeed without assistance.

The distinction is between continuing to pursue a goal and continuing an ineffective response.

There is also a terminology complication worth recognising. In the Utrecht study, the characteristic flexible was defined specifically as the ability to switch readily between working and resting. This is different from changing search tactics during a task, although both involve adapting behaviour to changing circumstances. The same word can therefore refer to different behavioural capacities depending on how researchers define and measure it.

When persistence becomes frustration

Persistence is often discussed alongside motivation and determination, but a dog that continues trying to reach an unavailable goal may also experience frustration.

Frustration occurs when access to an expected or desired outcome is blocked. It can increase arousal and produce more vigorous attempts to obtain the goal, including repeated actions, vocalisation or agitation. These behaviours may resemble increased motivation, although the dog’s emotional state and subsequent performance may be quite different.

Dickinson and Feuerbacher (2025) investigated the effects of frustration on search-and-rescue dogs by comparing a frustration-inducing condition with moderate physical exercise. The researchers measured heart rate, heart-rate variability and performance on a subsequent scent detection task.

Following the frustration condition, the dogs showed a significant reduction in heart-rate variability and took longer to perform their trained final response to the target odour. The researchers also observed more false-negative responses after frustration: five, compared with one in the baseline condition and two following exercise.

The study involved eleven search-and-rescue dogs, and the small number of errors limits what can be concluded about detection accuracy. Nevertheless, the physiological changes and increased response latency suggest that even relatively mild frustration can affect subsequent performance. This is relevant because some training approaches deliberately restrict access to rewards or create obstacles to increase a dog’s persistence.

The study does not establish how persistence is best developed, nor does it suggest that every difficult task necessarily causes harmful frustration. It does, however, provide a reason to examine whether increasing frustration actually improves the behaviour a trainer wants to develop. A dog that becomes more agitated or works more forcefully is not necessarily searching more effectively.

4. Working independently and cooperatively: the handler’s role

Detection dogs usually work with a human handler, but effective searching often requires the dog to make decisions without constant human direction. The dog has access to olfactory information that its handler cannot perceive directly. If it depends excessively on the handler’s movements or expectations, its searching may be influenced by human cues rather than the odour itself.

Lazarowski et al. (2020) discuss research in which candidate explosives detection dogs were presented with misleading human pointing gestures that conflicted with olfactory information. Dogs that ignored the inaccurate pointing gesture were more likely to be selected for detection work than those that followed it. This suggests that independence can be particularly important when human and olfactory information conflict.

However, successful detection work also requires cooperation. A handler may need to direct a dog towards an area, interrupt its activity, ask it to search again, or receive an indication that a target has been located. Some detection roles require dogs to work considerable distances away while remaining responsive to directional instructions. The ability to work independently must therefore coexist with the ability to respond to relevant human input.

Knowing when to seek assistance

One particularly interesting aspect of this relationship concerns how dogs behave when they cannot solve a problem independently. In unsolvable-task experiments, researchers may measure whether a dog continues attempting to obtain an inaccessible reward or redirects its attention towards a nearby person.

Lazarowski et al. (2020) report a study in which looking back and forth between the inaccessible reward and a human predicted later placement as a detection dog, whereas continued independent persistence was less favourable.

Such behaviour is often interpreted as a form of help-seeking, although the precise meaning of a dog’s attention towards a person depends on the task and its previous experience. The finding illustrates why independence should not be equated with solving every problem alone. In some circumstances, involving the handler provides access to assistance or information that allows the task to continue.

A successful working relationship consequently involves decisions about when to investigate independently, when to respond to direction, and when human involvement can help resolve a problem. The appropriate degree of independence also depends on the task. Dogs working at a distance from their handlers may need different combinations of autonomous searching and responsiveness from those conducting closely directed searches.

5. Working under real conditions: environmental soundness, arousal and resilience

The demands of detection work extend beyond finding odours. Dogs may need to search unfamiliar buildings, negotiate difficult surfaces, work near traffic or large groups of people, and continue performing despite noise, movement and other environmental stimuli. These conditions introduce behavioural and physical demands that can interfere with searching even when a dog has strong olfactory motivation.

Environmental soundness and resilience

Environmental soundness refers broadly to a dog’s ability to function effectively in its working environment without excessive disruption from unfamiliar or potentially stressful stimuli. Researchers commonly assess responses to unfamiliar objects, sudden noises, unusual surfaces, stairs and other environmental challenges.

An initial reaction does not necessarily reveal how well a dog can cope. The duration of the response and the ability to recover and resume activity can be equally informative. Lazarowski et al. (2020) describe how behavioural evaluations distinguish between immediate reactions to startling stimuli and subsequent recovery. A brief startle followed by rapid recovery may have different implications from prolonged avoidance or difficulty returning to the task.

The related concept of resilience concerns recovery from stress or adversity. In the Utrecht study, resilience was among the characteristics professional handlers considered especially important, alongside confidence, low insecurity and low emotional reactivity. These characteristics matter because a dog that becomes distressed or inhibited by its surroundings may struggle to perform even a familiar search task.

Arousal and the ability to regulate activity

Working dogs are often selected for high activity levels and strong motivation, but greater arousal does not necessarily produce better performance.

Arousal affects attention, learning, decision-making and physiological functioning. A certain level of activation may support sustained work, while excessive arousal can interfere with the very behaviours required for accurate detection.

Lazarowski et al. (2020) discuss behavioural indicators of potentially excessive working arousal, including frantic searching, agitation, vocalisation and difficulty navigating the search environment effectively. Heavy panting can also interfere with scent investigation because panting and active sniffing compete with one another.

The same review discusses off-duty calmness, or the ability to settle when not working. A dog may need to sustain activity during demanding searches while also being capable of recovering and resting afterwards. This distinction is particularly relevant because activity level, working motivation and emotional regulation are sometimes treated as interchangeable characteristics, although they describe different aspects of behaviour.

Physical suitability

Detection tasks also impose physical demands, and these differ substantially between working environments. Jamieson and colleagues (2017), reviewing detection-dog characteristics with particular attention to wildlife detection, identified athleticism and stamina among the important qualities for fieldwork.

A dog searching large outdoor areas may need to maintain physical activity over difficult terrain, while one working in buildings may encounter confined spaces, stairs or unfamiliar surfaces. The physical demands of a task also interact with behavioural characteristics. A dog may remain highly motivated to search while fatigue, heat or physical discomfort gradually reduce its effectiveness.

For wildlife detection dogs, the ability to work without pursuing animals encountered during the search may also be important, even when the dog has strong hunting-related motivation. These examples illustrate why a desirable characteristic cannot be evaluated entirely independently of the job the dog is expected to perform.

6. What actually predicts success? Evidence from behavioural testing and professional experience

The characteristics discussed so far come from several kinds of research, and it is worth considering what each can tell us. Studies asking experienced handlers to describe desirable working dogs provide insight into professional knowledge and selection practices. However, the traits professionals value are not automatically the same as those that have been experimentally demonstrated to predict successful working outcomes. This distinction is particularly apparent when comparing the recent questionnaire studies with research using standardised behavioural assessments.

What experienced handlers look for

The 2026 Utrecht study by Roulaux and colleagues identified 24 characteristics through interviews with professional handlers and trainers, then asked participants to rate their ideal scent detection dog and indicate how much deviation they would tolerate when selecting an actual dog.

Professionals were particularly reluctant to compromise on scent orientation, persistence, independence, resilience, confidence, environmental stability, and low levels of insecurity and negative emotional reactivity. Some characteristics, however, were considered more amenable to development through training.

Precision was one example. Professional handlers were more willing than recreational handlers to accept initially imprecise searching, and some described training methods for improving it.

Possessiveness was another: professional respondents generally valued greater possessiveness than recreational handlers, but were also more willing to accept deviations from their ideal, partly because they considered this characteristic responsive to training.

These findings are useful because they show how experienced professionals distinguish between characteristics they regard as fundamental and those they believe can be developed. They are still judgements about desirable dogs, rather than direct demonstrations that particular characteristics cause better detection performance.

Can behavioural tests predict working outcomes?

Lazarowski and colleagues (2021) investigated this question by evaluating a structured behavioural assessment in a group of 60 candidate detection dogs. The dogs were tested at approximately three, five and eleven months of age, and again towards the completion of their training programme.

The assessments included measures of hunting behaviour, air scenting, task engagement, reward-related behaviour, responses to startling or unfamiliar stimuli, and reactions to challenging environments. Some measures predicted later selection into working roles as early as three months. For example, aspects of working arousal, emotional reactivity and environmental responses were associated with subsequent selection.

However, the predictive value of particular measures differed across ages. At three months, the broader measure labelled work drive did not predict selection, although working arousal did. At five months, none of the performance-test variables predicted the final outcome.

The outcome measure also deserves attention: the study examined selection into operational roles or retention for breeding, rather than long-term detection accuracy across different working environments. Nevertheless, it provides evidence that some behavioural characteristics can be assessed reliably and that particular measures are associated with later programme outcomes. The findings also illustrate why a general judgement about a dog’s working potential may be less informative than examining specific behaviours.

Does breed predict detection ability?

Breed preferences are another important aspect of detection-dog selection, although the evidence is complicated by differences in breeding histories, training practices and the types of work for which particular breeds are commonly selected.

Salamon and colleagues (2026) surveyed explosives detection professionals from four European countries about preferred breeds and important working characteristics. Belgian Malinois and German Shepherds dominated the preferences, although Labrador Retrievers and Springer Spaniels were also frequently included among suitable breeds.

The researchers then compared experts’ perceptions of breeds’ olfactory abilities with previously published experimental results. They found some striking discrepancies.

Border Collies, for example, received relatively low ratings for olfactory ability from professionals, despite performing well in an experimental olfactory task. The researchers suggested that characteristics such as search speed may influence how experts judge olfactory ability. A dog that searches more slowly may be perceived as having a poorer sense of smell even if it can detect the target successfully.

Breed preferences may also reflect practical considerations beyond detection performance, including availability, established training practices, working environments and familiarity with particular breeds. There is substantial variation between individual dogs within breeds, and an experimental food-search task does not replicate the full demands of professional detection work.

Consequently, neither breed reputation nor a single measure of olfactory performance provides a complete assessment of suitability.

Why defining the characteristics matters

One recurring problem in detection-dog research is that familiar terms are not always used consistently. Drive, focus, flexibility, persistence and trainability can refer to several overlapping behaviours, depending on the researcher, assessment method and working context.

A dog that remains engaged in searching may be described as persistent, highly motivated or focused. Yet those labels do not tell us whether it changes tactics when necessary, how it responds to frustration, or whether it can disengage when instructed.

Similarly, an assessment of independence may measure the ability to search without handler guidance, reluctance to seek assistance, or reduced responsiveness to human cues. These are related, but they need not produce the same working outcomes.

For behavioural assessments to be useful, researchers need to specify what is being measured and how it relates to the task. This becomes particularly important when attempting to predict future working performance, compare results across programmes, or make breeding and training decisions.

Conclusion

Research into scent detection dogs increasingly describes working ability through a combination of behavioural, motivational, cognitive and physical characteristics. Olfactory ability remains fundamental, but it is the dog’s behaviour that determines how effectively that capacity is used during a search. The motivation to investigate odours must be accompanied by sustained task engagement, while persistence is most useful when the dog can adjust its approach as conditions change.

Independent searching also needs to be compatible with cooperation, and the dog must be able to manage the environmental and physical demands of the particular task.

There is no single behavioural characteristic that establishes whether a dog will succeed in detection work, and the evidence for individual traits varies. Professional evaluations help identify what experienced handlers consider important, while behavioural studies can investigate whether those characteristics predict measurable outcomes.

Understanding these distinctions gives us a more precise way to describe how dogs search, why their working styles differ, and which aspects of their behaviour may be relevant to selection and training. It also allows us to move beyond broad judgements about a dog’s drive or working ability and examine the specific behaviours that contribute to effective scent detection.

References

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