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Scent marks play a crucial role in both territorial and sexual communication in many species. We investigated how free-ranging dogs respond to scent marks from individuals of different identities in terms of sex and group, across varying strategic locations within their territory. Both male and female dogs showed heightened interest in scent marks compared to control, exhibiting stronger territorial responses,. with males being more territorial than females. Overmarking behaviour was predominantly observed in males, particularly in response to male scent marks and those from neighbouring groups. Behavioural cluster analysis revealed distinct responses to different scent marks, with neighbouring group male scents eliciting the most distinct reactions. Our findings highlight the multifaceted role of scent marks in free-ranging dog communication, mediating both territorial defence and intrasexual competition. The differential responses based on the identity and gender of the scent-marker emphasize the complexity of olfactory signalling in this species. This study contributes to understanding the social behaviour of dogs in their natural habitat, and opens up possibilities for future explorations in the role of olfactory cues in the social dynamics of the species.

Palatability of food is driven by multiple factors like taste, smell, texture, freshness, etc. and can be very variable across species. There are classic examples of local adaptations leading to speciation, driven by food availability. Urbanization across the world is causing rapid decline of biodiversity, while also driving local adaptations in some species. Free-ranging dogs are an interesting example of adaptation to a human-dominated environment across varied habitats. They have co-existed with humans for centuries and are a perfect model system for studying local adaptations. We attempted to understand a specific aspect of their scavenging behaviour in India: citrus aversion. Pet dogs are known to avoid citrus fruits and food contaminated by them. In India, lemons are used widely in the cuisine, and discarded in the garbage. Hence, free-ranging dogs, that typically are scavengers of human leftovers, are likely to encounter lemons and lemon-contaminated food on a regular basis. We carried out a population level experiment to test response of free-ranging dogs to chicken contaminated with various parts of lemon. The dogs avoided chicken contaminated with lemon juice the most. Further, when provided with chicken dipped in three different concentrations of lemon juice, the lowest concentration was most preferred. A survey confirmed that the local people use lemon in their diet extensively and also discard these with the leftovers. People avoided giving citrus contaminated food to their pets but did not follow the same caution for free-ranging dogs. This study revealed that free-ranging dogs in West Bengal, India, are well adapted to scavenging among citrus-contaminated garbage and have their own strategies to avoid the contamination as far as possible, while maximizing their preferred food intake., Comment: Includes supplementary information

The human face is a multi-signal system continuously transmitting information of identity and emotion. In shared human-animal environments, the face becomes a reliable tool of heterospecific recognition. Because humans display mixed behaviour and pose differential risk to animals, adaptable decision-making based on recognition and classification of humans confer a fitness benefit. The human-dog dyad is an ideal model to study heterospecific recognition due to their shared history, niche overlap, and cognitive co-evolution. Multiple studies on pet dogs have examined their human facial information processing. However, no study has examined these perceptual abilities in free-living populations in their natural habitat where the human-dog relationship is more complex and impacts survival. Comprehensive behavioural analysis of 416 free-ranging dogs in an approach-based task with differential facial occlusion of a human, demonstrated that these dogs recognize and discriminate between familiar and unfamiliar people. Negative behaviours like aggression and avoidance were unlikely to be displayed. Inner facial components like eyes, nose and mouth were more important than outer components like hair in human recognition. Unlike in pet dogs, the occlusion of even a single inner component of the face prevented recognition by facial cue alone. Personality and habitat conditions influenced the behavioural strategy adopted by the dogs too. Considering the ambiguous nature of human interactions, recognition and response in free-ranging dogs relied on dual assessment of identity and intent of a human based, in part, on their ontogeny. Such a cue-processing system highlights the selection pressures inherent in the unpredictable environment of free-living populations., Comment: 6 figures, 2 tables, supplementary material included

Seasonal fairs, bustling with human activity, provide a unique environment for exploring the intricate interplay between humans and free-ranging dogs. This study investigated these interactions during seasonal fairs in Nadia and Bardhaman districts, West Bengal, India. Across 13 fairground sites, we explore how human footfall and resource availability impact dog behavior, with a particular emphasis on cognitive mechanisms. Data collection occurred from December to March, comprising three sessions - initial, middle, and end, each on three randomly selected days. Employing spot census and scan sampling methods, observers documented GPS locations, sex, and behaviors of free-ranging dogs. Videos captured interactions within the fair environment, revealing cognitive processes. Our analysis revealed a notable increase in human activity during the middle phase, coinciding with a rise in dog abundance. Dogs predominantly foraged, exhibited gait, and remained vigilant, their numbers positively associated with resource availability. Proximity to the fairground significantly shaped dog behavior, indicating cognitive processes in decision-making. Dogs closer to the fair demonstrated consistent behavior, likely due to immediate resource access, implying sophisticated cognitive mapping and resource utilization. Conversely, dogs from farther distances exhibited lower consistency and heightened aggression, intensifying foraging, gait, and vigilance activities, suggesting cognitive adaptations to resource scarcity and competition. These findings underscore the intricate relationship between human activity, resource availability, and the behavior and cognition of free-ranging dogs during seasonal fairs. They offer insights into the ecological dynamics of free-ranging dogs in human-influenced landscapes, emphasizing the necessity for comprehensive management strategies in urban and peri-urban environments., Comment: 3 figures, supplementary material included

Individual human recognition is important for species that live in close proximity to humans. Numerous studies on domesticated species and urban-adapted birds have highlighted this ability. One such species which is heavily reliant on humans is the free-ranging dog. Very little knowledge exists on the amount of time taken by free-ranging dogs to learn and remember individual humans. Due to their territorial nature, they have a high probability of encountering the same people multiple times on the streets. Being able to distinguish individual humans might be helpful in making decisions regarding people from whom to beg for food or social reward. We investigated if free-ranging dogs are capable of identifying the person rewarding them and the amount of time required for them to learn it. We conducted field trials on randomly selected adult free-ranging dogs in West Bengal, India. On Day 1, a choice test was conducted. The experimenter chosen did not provide reward while the other experimenter provided a piece of boiled chicken followed by petting. The person giving reward on Day 1 served as the correct choice on four subsequent days of training. Day 6 was the test day when none of the experimenters had a reward. We analyzed the choice made by the dogs, the time taken to approach during the choice tests, and the socialization index, which was calculated based on the intensity of affiliative behaviour shown towards the experimenters. The dogs made correct choices at a significantly higher rate on the fifth and sixth days, as compared to Day 2, suggesting learning. This is the first study aiming to understand the time taken for individual human recognition in free-ranging dogs and can serve as the scaffold for future studies to understand the dog-human relationship in open environments, like urban ecosystems.

Free-ranging dogs (FRDs) in human-dominated areas encounter obstacles such as noise, pollution, limited food sources, and anthropogenic disturbance while resting. Since FRDs have survived as a population in India, as in many other parts of the Global South for centuries, they provide a unique opportunity to study adaptation of animals to the human-dominated urban landscape. We documented factors impacting resting behaviour and site preferences in three states of India, for 284 dogs, leading to 6047 observations over 3 years. 7 physical parameters of the resting sites, along with the biological factors like mating and pup-rearing and time of day affected their choice of resting sites. The frequency-rank distribution of the unique combinations in which the parameters were selected followed a Power law distribution, which suggests underlying biological reasons for the observed preferences. Further, 3 of these parameters showed maximum consistency of choice in terms of the sub-parameters selected, explaining 30% of the observations. FRDs prefer to rest close to their resource sites within the territory, at a place that enabled maximum visibility of the surroundings. They chose such sites in the core of the territory for sleeping. At other times, they chose such sites away from the core, and were less restive, thus allowing for immediate response in case of intrusion or threat. They generally avoided anthropogenic disturbance for sleeping, and preferred areas with shade.Incorporating these aspects into urban management plans can promote human-dog cooperation and reduce situations of conflict. We envisage more inclusive urban areas in the future, that can allow for co-existence of the humans and their oldest companions in the commensal relationship that has been maintained for hundreds of generations of dogs in this part of the world., Comment: 2 figures, 2 tables, ESM

Foraging and acquiring of food is a delicate balance between managing the costs, both energy and social, and individual preferences. Previous research on the solitary foraging of free ranging dogs showed that they prioritized the nutritionally highest valued food patch first but do not ignore other less valuable food either, displaying typical scavenger behaviour. The current experiment was carried out on groups of dogs with the same set up to see the change in foraging strategies, if any, under the influence of social cost like intra-group competition. We found multiple differences between the strategies of dogs foraging alone versus in groups with competition playing an implicit role in the decision making of dogs when foraging in groups. Dogs were able to continually assess and evaluate the available resources in a patch and adjust their behaviour accordingly. Foraging in groups also provided benefits of reduced individual vigilance. The various decisions and choices made seemed to have a basis in the optimal foraging theory wherein the dogs harvested the nutritionally richest patch possible with the least risk and cost involved but was willing to compromise if that was not possible. This underscores the cognitive, quick decision-making abilities and adaptable behaviour of these dogs.

Rapid urbanization is a major cause of habitat and biodiversity loss and human-animal conflict. While urbanization is inevitable, we need to develop a good understanding of the urban ecosystem and the urban-adapted species in order to ensure sustainable cities for our future. Scavengers play a major role in urban ecosystems, and often, urban adaptation involves a shift towards scavenging behaviour in wild animals. We carried out an experiment at different sites in the state of West Bengal, India, to identify the scavenging guild within urban habitats, in response to human provided food. Our study revealed a total of 17 different vertebrate species were identified across sites over 498 sessions of observations. We carried out network analysis to understand the dynamics of the system, and found that the free-ranging dog and common mynah were key species within the scavenging networks. This study revealed the complexity of scavenging networks within human-dominated habitats., Comment: 5 figures, ESM present

Interaction with its immediate environment determines the ecology of an organism. Species present in any habitat, wild or urban, may face extreme pressure due to sudden perturbations. When such disturbances are unpredictable, it becomes more challenging to tackle. Implementation of specific strategies is therefore essential for different species to overcome adverse situations. Numerous biotic and abiotic factors can alter the dynamics of a species. Anthropogenic disturbance is one such factor that has considerable implications and also the potential to impact species living in the proximity of human habitats. We investigated the response of an urban adapted species to a sudden surge in human footfall or overcrowding. Dogs (Canis lupus familiaris) living freely in the streets of developing countries experience tremendous anthropogenic pressure. It is known that human movement in an area can predict the behaviour of these dogs by largely influencing their personalities. In the current study, we observed a strong effect of high and sudden human footfall on the abundance and behavioural activity of dogs. A decline in both the abundance of dogs and behavioural activities was seen with the increase in human movement. Further investigation over a restricted temporal scale revealed reinstated behavioural activity but non-restoration of population abundance. This provides important evidence on the extent to which humans influence the behaviour of free-ranging dogs in urban environments., Comment: 1 figure

Canids display a vast diversity of social organizations, from solitary-living to pairs to packs. Domestic dogs have descended from pack-living gray wolf-like ancestors. Unlike their group living ancestors, free-ranging dogs are facultatively social, preferring to forage solitarily. They are scavengers by nature, mostly dependent on human garbage and generosity for their sustenance. Free-ranging dogs are highly territorial, often defending their territories using vocalizations. Vocal communication plays a critical role between inter and intraspecies and group interaction and maintaining their social dynamics. Barking is the most common among the different types of vocalizations of dogs. Dogs have a broad hearing range and can respond to sounds over long distances. Domestic dogs have been shown to have the ability to distinguish between barking in different contexts. Since free-ranging dogs regularly engage in various kinds of interactions with each other, it is interesting to know whether they are capable of distinguishing between vocalizations of their own and other groups. In this study, a playback experiment was used to test if dogs can distinguish between barking of their own group member from a non-group member. Though dogs respond to barking from other groups in territorial exchanges, they did not respond differently to the self and other group barking in the playback experiments. This suggests a role of context in the interactions between dogs and opens up possibilities for future studies on the comparison of the responses of dogs in playback experiments with their natural behavior through long-term observations., Comment: 6 figure, 2 tables

The domestic dog is known to have evolved from gray wolves, about 15,000 years ago. They majorly exist as free-ranging populations across the world. They are typically scavengers and well adapted to living among humans. Most canids living in and around urban habitats tend to avoid humans and show crepuscular activity peaks. In this study, we carried out a detailed population-level survey on free-ranging dogs in West Bengal, India, to understand the activity patterns of free-ranging dogs in relation to human activity. Using 5669 sightings of dogs, over a period of 1 year, covering the 24 hours of the day, we carried out an analysis of the time-activity budget of free-ranging dogs to conclude that they are generalists in their habit. They remain active when humans are active. Their activity levels are affected significantly by age class and time of the day. Multivariate analysis revealed the presence of certain behavioural clusters on the basis of time of the day and energy expenditure in the behaviours. In addition, we provide a detailed ethogram of free-ranging dogs. This, to our knowledge, is the first study of this kind, which might be used to further study the eco-ethology of these dogs., Comment: 5 figures

Species inhabiting urban environments experience enormous anthropogenic stress. Behavioural plasticity and flexibility of temperament are crucial to successful urban-adaptation. Urban free-ranging dogs experience variable human impact, from positive to negative and represent an ideal system to evaluate the effects of human-induced stress on behavioural plasticity. We tested 600 adult dogs from 60 sites across India, categorised as high - HF, low - LF, and intermediate - IF human flux zones, to understand their sociability towards an unfamiliar human. Dogs in the HF and IF zones were bolder and as compared to their shy counterparts in LF zones. The IF zone dogs were the most sociable. This is the first-ever study aimed to understand how the experiences of interactions with humans in its immediate environment might shape the responses of an animal to humans. This is very relevant in the context of human-animal conflict induced by rapid urbanization and habitat loss across the world., Comment: 3 figures, 14 pages of supplementary material

Apparently random events in nature often reveal hidden patterns when analysed using diverse and robust statistical tools. Power-law distributions, for example, project diverse natural phenomenon, ranging from earthquakes1 to heartbeat dynamics2 onto a common platform of statistical self-similarity. A large range of human languages are known to follow a specific regime of power-law distributions, the Zipf-Mandelbrot law, in addition to showing properties like the Pareto principle and Shannon entropy3,4. Animal behaviour in specific contexts have been shown to follow power-law distributions5,6. However, the entire behavioural repertoire of a species has never been analysed for the existence of underlying patterns. Here we show that the frequency-rank data of randomly sighted behaviours at the population level of free-ranging dogs follow a scale-invariant power-law behaviour. While the data does not display Zipfian trends, it obeys the Pareto principle and Shannon entropy rules akin to languages. Interestingly, the data also exhibits robust self-similarity patterns at different scales which we extract using multifractal detrended fluctuation analysis7. The observed multifractal trends suggest that the probability of consecutive occurrence of behaviours of adjacent ranks is much higher than behaviours widely separated in rank. Since we observe such robust trends in random data sets, we hypothesize that the general behavioural repertoire of a species is shaped by a syntax similar to languages. This opens up the prospect of future multifractal and other statistical investigations on true time series of behavioural data to probe the existence of possible long and short-range correlations, and thereby develop predictive models of behaviour., Comment: 2 figures, 4 pages supplementary information

Mammalian offspring require parental care, at least in the form of suckling during their early development. While mothers need to invest considerable time and energy in ensuring the survival of their current offspring, they also need to optimize their investment in one batch of offspring in order to ensure future reproduction and hence lifetime reproductive success. Free-ranging dogs live in small social groups, mate promiscuously, and lack the cooperative breeding biology of other group living canids. They face high early life mortality, which in turn reduces fitness benefits of the mother from a batch of pups. We carried out a field based study on free-ranging dogs in India to understand the nature of parental care provided by mothers at different stages of pup development. Using behavioural patterns of mother-pup interactions, we draw up a timeline of pup ontogeny. Our analysis reveals that mothers cleverly reduce investment in energy intensive active care and increase passive care as the pups grow older, thereby keeping overall levels of parental care more or less constant over pup age., Comment: Submitted manuscript

Cooperative breeding is an excellent example of altruistic cooperation in social groups. Domestic dogs have evolved from cooperatively hunting and breeding ancestors, but have adapted to a facultatively social scavenging lifestyle on streets, and solitary living in human homes. Pets typically breed and reproduce under human supervision, but free-ranging dogs can provide insights into the natural breeding biology of dogs. We conducted a five year long study on parental care of free-ranging dogs in India. We observed widespread alloparenting by both adult males and females. Allomothers provided significantly less care that the mothers, but the putative fathers showed comparable levels of care with the mothers. However, the nature of care varied; mothers invested more effort in feeding and allogrooming, while the putative fathers played and protected more. We were unsure of the relatedness of the pups with the putative fathers, but all the allomothers were maternal relatives of the pups, which provides support for both the benefit-of-philopatry and assured fitness returns hypotheses. Free-ranging dogs are not cooperative breeders like wolves, but are more similar to communal breeders. Their breeding biology bears interesting similarities with the human joint family system., Comment: Submitted manuscript

Parent-offspring conflict theory predicts the emergence of weaning conflict between a mother and her offspring arising from skewed relatedness benefits. Empirical observations of weaning conflict has not been carried out in canids. In a field-based study on free-ranging dogs we observed that suckling bout durations reduce, proportion of mother-initiated suckling bouts reduce and mother-initiated suckling terminations increase, with pup age. We identified the 7th - 13th week period of pup age as the zone of conflict between the mother and her pups, beyond which suckling solicitations cease, and before which suckling refusals are few. We also report for the first time milk theft by pups who take advantage of the presence of multiple lactating females, due to the promiscuous mating system of the dogs. This behaviour, though apparently disadvantageous for the mothers, is perhaps adaptive for the dogs in the face of high mortality and competition for resources., Comment: 3 figures, 1 table

Dominance and subordinate behaviours are important ingredients in the social organizations of group living animals. Behavioural observations on the two eusocial species \textit{Ropalidia marginata} and \textit{Ropalidia cyathiformis} suggest varying complexities in their social systems. The queen of R. cyathiformis is an aggressive individual who usually holds the top position in the dominance hierarchy although she does not necessarily show the maximum number of acts of dominance, while the R. marginata queen rarely shows aggression and usually does not hold the top position in the dominance hierarchy of her colony. These differences are reflected in the distribution of dominance-subordinate interactions among the hierarchically ranked individuals in both the species. The percentage of dominance interactions decrease gradually with hierarchical ranks in R. marginata while in R. cyathiformis it first increases and then decreases. We use an agent-based model to investigate the underlying mechanism that could give rise to the observed patterns for both the species. The model assumes, besides some non-interacting individuals, that the interaction probabilities of the agents depend on their pre-differentiated winning abilities. Our simulations show that if the queen takes up a strategy of being involved in a moderate number of dominance interactions, one could get the pattern similar to R. cyathiformis, while taking up the strategy of very low interactions by the queen could lead to the pattern of R. marginata. We infer that both the species follow a common interaction pattern, while the differences in their social organization are due to the slight changes in queen as well as worker strategies. These changes in strategies are expected to accompany the evolution of more complex societies from simpler ones., Comment: 13 pages, 6 figures, 2 tables

Indian free ranging dogs live in a carbohydrate rich environment as scavengers in and around human settlements. They rarely hunt and consequently do not encounter rich sources of protein. Instead they have adapted to a diet of primarily carbohydrates. As descendants of the exclusively carnivorous wolves, they are subjected to the evolutionary load of a physiological demand for proteins. To meet their protein needs they resort to a thumb rule, if it smells like meat, eat it. Pups face high competition from group and non group members and are in a phase of rapid growth with high protein demands. Following the thumb rule, then they can acquire more protein at the cost of increased competition and reduced supplementary non protein nutrition. However, if the mother supplements their diet with protein rich regurgitates and milk, then the pups can benefit by being generalists. Using a choice test in the field we show that while adults have a clear preference for meat, pups have no such preference, and they even eat degraded protein eagerly. Thus the thumb rule used by adult dogs for efficient scavenging is not innate, and needs to be learned. The thumb rule might be acquired by cultural transmission, through exposure to meat in the regurgitate of the mother, or while accompanying her on foraging trips., Comment: 26 pages, 2 figures, 2 tables, 2 supplementary figures, unpublished

Canids display a wide diversity of social systems, from solitary to pairs to packs, and hence they have been extensively used as model systems to understand social dynamics in natural systems. Among canids, the dog can show various levels of social organization due to the influence of humans on their lives. Though the dog is known as man's best friend and has been studied extensively as a pet, studies on the natural history, ecology and behaviour of dogs in a natural habitat are rare. Here we report results of an extensive population-level study conducted through one-time censuses in urban India to understand the ecoethology of free-ranging dogs. We built a model to test if the observed groups could have been formed through random associations while foraging. Our modeling results suggest that the dogs, like all efficient scavengers, tend to forage singly but also form random uncorrelated groups. A closer inspection of the group compositions however reveals that the foraging associations are non-random events. The tendency of adults to associate with the opposite sex in the mating season and of juveniles to stay close to adults in the non-mating season drives the population towards aggregation, in spite of the apparently random nature of the group size distribution. Hence we conclude that to be or not to be social is a matter of choice for the free-ranging dogs, and not a matter of chance.

Animals that scavenge in and around human localities need to utilize a broad range of resources. Preference for any one kind of food, under such circumstances, might be inefficient. Indian free-ranging dogs, Canis lupus familiaris are scavengers that are heavily dependent on humans for sustaining their omnivorous diet. The current study suggests that because of evolutionary load, these dogs, which are descendants of the decidedly carnivorous gray wolf, still retain a preference for meat though they live on carbohydrate-rich resources. The plasticity in their diet probably fosters efficient scavenging in a competitive environment, while a thumb rule for preferentially acquiring specific nutrients enables them to sequester proteins from the carbohydrate-rich environment.

The parent-offspring conflict theory is an interesting premise for understanding the dynamics of parental care. However, this theory is not easy to test empirically, as exact measures of parental investment in an experimental set-up are difficult to obtain. We have used the Indian feral dog as a model system to test the POC theory in their natural habitat in the context of the mother's tendency to share food given by humans with her pups in the weaning and post-weaning stage. Our behavioural bioassay convincingly demonstrates an increase of conflict and decrease of cooperation by the mother with her offspring over a span of 4-6 weeks. We also demonstrate that the conflict is intentional, and is not influenced by the hunger levels of the pups or the litter size., Comment: 20 pages, 4 figures, electronic supplementary material (2 pages), yet to be published