Florence Gaunet

Dogs can detect volatile organic compounds (VOCs) associated with infectious diseases, but their ability to distinguish between symptomatic and asymptomatic SARS-CoV-2 infections has not been fully established. In this exploratory proof-of-concept study with a limited number of dogs, eight non-working dogs (without experience in scent detection) began training with either symptomatic or asymptomatic Delta samples; seven reached the testing phase and were then evaluated on the alternate group to assess cross-generalization. Training initially used a yes/no protocol but was adapted to a line-up design after poor performance. When presented with novel Delta samples from the other category, dogs significantly discriminated them from controls, achieving a mean sensitivity of 71% and a specificity of 51%, with no difference between training groups. In contrast, performance dropped when dogs were tested with a small number of asymptomatic Omicron-positive samples from vaccinated individuals, with a mean sensitivity of 35% and a specificity of 55%. Dogs can thus generalize across symptomatic and asymptomatic COVID-19 cases for the Delta variant; performance decreased for Omicron samples, likely due to altered VOC profiles in vaccinated individuals. While proof-of-concept feasibility was demonstrated with a line-up protocol for detecting asymptomatic scent, detection dogs should not currently be recommended for large-scale screening; the findings underscore the need for standardized protocols and variant-specific retraining.

Dogs can detect volatile organic compounds (VOCs) associated with infectious diseases, but their ability to distinguish between symptomatic and asymptomatic SARS-CoV-2 infections has not been fully established. In this study, eight naïve dogs began training with either symptomatic or asymptomatic Delta samples; seven reached the testing phase and were then evaluated on the alternate group to assess cross-generalization. Training initially used a yes/no protocol but was adapted to a line-up design after poor performance. When presented with novel Delta samples, dogs significantly discriminated them from controls, achieving a mean sensitivity of 71% and specificity of 51%, with no difference between training groups. In contrast, performance dropped when dogs were tested with asymptomatic Omicron samples from vaccinated individuals, with a mean sensitivity of 55%. These results show that dogs can generalize across symptomatic and asymptomatic COVID-19 cases for the Delta variant but fail to detect Omicron reliably, likely due to altered VOC profiles in vaccinated individuals. While proof-of-concept feasibility was demonstrated with a line up protocol for detecting asymptomatic scent, detection dogs should not currently be recommended for large-scale screening, but findings underscore the need for standardized protocols and variant-specific retraining.

Behavioural synchronization in dogs has been examined separately at intraspecific and interspecific levels. This study is the first to compare dogs’ behavioural synchronization and gaze behaviour when with a familiar person (with FP) compared to a familiar dog (with FD), while walking in an outdoor environment. Twenty dogs were observed under the two experimental conditions. We hypothesized that dogs would demonstrate stronger location and activity synchronization with an FD than with an FP due to similar locomotor patterns, while showing greater gaze attention towards the FP compared to the FD. Our hypothesis was partially confirmed. The results revealed a significantly shorter distance between dogs and the FD than between dogs and the FP. Dogs exhibited a smaller speed difference with the FD than with the FP, but only if they did not cohabit with other dogs. No significant differences were observed in body alignment or gaze behaviour between the two experimental conditions. Our results point to behavioural synchronization as a new instance of evolutionary convergence, as well as daily experiences, here cohabiting with other dogs, as a factor influencing dogs’ ability to synchronize with individuals from different species. This study enhances our understanding of canine cognition in conspecific versus heterospecific contexts.

Dogs’ behavioural synchronisation with humans is of growing scientific interest. However, studies lack a comprehensive exploration of the neurocognitive foundations of this social cognitive ability. Drawing parallels from the mechanisms underlying behavioural synchronisation in humans, specifically motor resonance and the recruitment of mirror neurons, we hypothesise that dogs’ behavioural synchronisation with humans is underpinned by a similar mechanism, namely interspecific motor resonance. Based on a literature review, we argue that dogs possess the prerequisites for motor resonance, and we suggest that interspecific behavioural synchronisation relies on the activation of both human and canine mirror neurons. Furthermore, interspecific behavioural studies highlight certain characteristics of motor resonance, including motor contagion and its social modulators. While these findings strongly suggest the potential existence of interspecific motor resonance, direct proof remains to be established. Our analysis thus paves the way for future research to confirm the existence of interspecific motor resonance as the neurocognitive foundation for interspecific behavioural synchronisation. Unravelling the neurocognitive mechanisms underlying this behavioural adjustment holds profound implications for understanding the evolutionary dynamics of dogs alongside humans and improving the day-to-day management of dog–human interactions.

Within species, vocal and auditory systems co-evolve to converge on a critical temporal acoustic structure that can be best produced and perceived. While dogs cannot produce articulated sounds, they respond to speech, raising the question as to whether this heterospecific receptive ability is shaped by exposure to speech or bounded by their own sensorimotor capacity. Acoustic analyses of vocalisations show that dogs’ main production rhythm is slower than the dominant (syllabic) speech rate, and that human dog-directed speech falls halfway in between. Comparative exploration of neural (electroencephalography) and behavioural responses to speech reveals that comprehension in dogs relies on a slower speech rhythm tracking (delta) than humans’ (theta), even though dogs are equally sensitive to human speech content and prosody. Thus, the dog audio-motor tuning differs from humans’, who vocally adjust their speech rate to this shared temporal channel.

Behavioural synchronization is a widespread skill in social species as it helps increase group cohesion among individuals. Such a phenomenon is involved in social interactions between conspecifics as well as between individuals from different species. Most importantly, familiarity and affiliation between interacting partners influence the degree of behavioural synchronization they would exhibit with each other. For example, in human–dog dyads, the more a dog is affiliated with its human partner, the more it behaves in a synchronous way with them. However, little is known about the ontogeny of such a behaviour, especially from an interspecific perspective. The aim of the present study was thus to investigate the existence and modalities of activity synchrony, a type of behavioural synchronization, between humans and puppies. To do so, we observed 29 dog puppies interacting with two different humans (familiar and unfamiliar experimenters). Puppy movements and general activity in relation to the human ones were observed. Results evidenced that puppies did exhibit locomotor synchrony with humans, but familiarity did not affect its degree. It is the first time that activity synchrony with human walk is evidenced in puppies, highly suggesting that dogs’ ability to behave in synchronization with humans seems to be genetically selected through the process of domestication, while the effect of familiarity on it might develop later during the individual ontogeny.

There has been scant research on the presence of stray dogs in cities. Studying their very considerable presence in Concepción (Chile) provided a unique opportunity to learn more about the different patterns of sociality and territoriality exhibited by the dog species. Via a set of case studies, we examined the behavior of urban dogs, adopting an ethnographic methodology. This yielded findings of the dogs’ cognitive, social and spatial adjustment abilities, i.e., their territorialities. Our hypothesis was validated: We found numerous types of sociability, we confirmed the presence of two previously established categories: family dogs (pets, guard dogs and beggars’ dogs) and stray dogs (dogs almost entirely unused to humans, aggressive dogs at the far end of the campus and feral dogs in the woods). We also identified three new ones: familiar stray dogs in packs (dogs both spatially and socially close to humans), pet-stray dogs (i.e., village dogs interacting closely with people) and free-roaming pet dogs. We conclude that an ongoing two-way bond between humans and animals allowed these dogs to became part of a city’s urban identity and explains the stray dogs’ plasticity in terms of adapting to the diversified urban habitat. We postulate that it was the human culture and range of urban areas in Concepción that gave rise to this unique diversity of sociospatial positioning and level of adjustment (e.g., dogs crossing crosswalks).

Guide dogs are working dogs that follow the verbal instructions of owners with severe visual impairments, leading them through the environment and toward goals such as a subway entrance (“Find the subway” instruction). During this process, guide dogs incidentally familiarize themselves with their environment. As such, they provide a unique animal model for studying wayfinding abilities in the canine species. In the present descriptive study, 23 skilled guide dogs travelled along a path once and were subsequently tested in a navigation task, with a blindfolded guide dog instructor as the handler. Dogs had difficulty reproducing the path (only 30.43% of the dogs succeeded) and returning (homing) along the previously travelled path (43.47% of the dogs succeeded). However, 80% of them successfully took a shortcut, and 86.95% a detour. This is the first description of the wayfinding abilities of dogs after a single discrete exploration of the path (incidental learning) in systematic experimental conditions. Errors, initiatives and success rates showed that dogs were able to keep track of the goal if the path was short, but errors increased with longer paths, suggesting segmented integration of path characteristics process, as demonstrated in humans. Additionally, errors on homing and detouring, both vital wayfinding tasks, were correlated, suggesting an effect of experience. Initiatives taken by the dogs further suggest flexibility of the spatial representation elaborated. Interestingly, we also found that homing was the only task to benefit from severe visual disability and regular exposure to new journeys, suggesting that these two factors influence the most important wayfinding task. This study therefore highlights qualitative and quantitative wayfinding abilities in the dog species, as well as the factors that account for them, after a single path exploration accompanied by natural ongoing motivation. In the wake of the discovery that dogs are sensitive to the magnetic field, our results provide the basis for developing systematic wayfinding tests for guide dogs.