Does novelty influence the foraging decisions of a scavenger?

Acquiring knowledge about the environment is crucial for survival. Animals, often driven by their exploratory tendencies, gather valuable information regarding food resources, shelter, mating partners, etc. However, neophobia, or avoiding novel environmental stimuli, can constrain their exploratory behaviour. While neophobia can reduce potential predation risks, decreased exploratory behaviour resulting from it may limit the ability to discover highly rewarding resources. Dogs (Canis familiaris) living in semi-urban and urban environments as free-ranging populations, although subject to various selection forces, typically have negligible predation pressure. These dogs are scavengers in human-dominated environments; thus, selection against object-neophobia can provide benefits when searching for novel food resources. Although captive pack-living dogs are known to be less neophobic than their closest living ancestors, wolves (Canis lupus), little is known about free-ranging dogs' behavioural responses to novel objects, particularly in foraging contexts. Using an object choice experiment, we tested 259 free-ranging dogs from two age classes, adult and juvenile, to investigate their object-neophobia in a scavenging context. We employed a between-subject study design, providing dogs with a familiar and a potentially novel object, both baited with equal, hidden food items. Adult and juvenile dogs significantly inspected the novel object first compared to the familiar one, even when the hidden food item was partially visible. To validate these findings, we compared novel objects with different strengths of olfactory cues (baited vs. false-baited) and found that they were inspected comparably by adults and juveniles. No significant differences were found in the latencies to inspect the objects, suggesting that free-ranging dogs may still be cautious when exploring their environments. These results indicate that free-ranging dogs, evidently from an early ontogenetic phase, do not show object-neophobia, as demonstrated by their preference for novel over familiar food sources. We conclude that little to no constraint of neophobia on exploratory behaviour in semi-urban and urban-dwelling animals can guide foraging decision-making processes, providing adaptive benefits.

Personality heterophily and friendship as drivers for successful cooperation.

Cooperation is widespread and arguably a pivotal evolutionary force in maintaining animal societies. Yet, proximately, what underlying motivators drive individuals to cooperate remains relatively unclear. Since 'free-riders' can exploit the benefits by cheating, selecting the right partner is paramount. Such decision rules need not be based on complex calculations and can be driven by cognitively less-demanding mechanisms, like social relationships (e.g. kinship, non-kin friendships, dyadic tolerance), social status (e.g. dominance hierarchies) and personalities (social and non-social traits); however, holistic evidence related to those mechanisms is scarce. Using the classical 'loose-string paradigm', we tested cooperative tendencies of a hierarchical primate, the long-tailed macaque (Macaca fascicularis). We studied three groups (n = 21) in their social settings, allowing partner choice. We supplemented cooperation with observational and experimental data on social relationships, dominance hierarchies and personality. Friendship and dissimilarities in non-social 'exploration' and 'activity-sociability' personality traits predicted the likelihood of cooperative dyad formation. Furthermore, the magnitude of cooperative success was positively associated with friendship, low rank-distance and dissimilarity in the activity-sociability trait. Kinship did not affect cooperation. While some findings align with prior studies, the evidence of (non-social) personality heterophily promoting cooperation may deepen our understanding of the proximate mechanisms and, broadly, the evolution of cooperation.

Behavioral, physiological, and genetic drivers of coping in a non-human primate.

Animals experience stressful situations, from predation to social conflicts, but mostly deal with them successfully. This adaptive mechanism, coping, reduces the adverse effects of stressors, and its failure may result in reduced fitness. Substantial inter-individual variation in coping is observed, yet little is known about how behavioral, physiological and genetic drivers regulate coping holistically and contribute to such variations. We assessed behavioral coping styles (n=30), emotional arousal (n=12), and personalities (n=32) of long-tailed macaques (Macaca fascicularis) and also investigated the association of coping with a valine/methionine polymorphism encoded by a critical human stress regulatory gene, catechol-O-methyltransferase (COMT) (n=26). Personality and the human equivalent COMT Val/Met polymorphism were associated with "nonaggression-based" and "aggression-based" coping styles. Compared to nonaggression-based, aggression-based copers maintained higher average facial temperatures, indicating potentially lower emotional arousal, as measured using infrared thermography. These findings demonstrate a complex interplay of various proximate mechanisms governing coping in a non-human primate.

Hand preference predicts behavioral responses to threats in Barbary macaques.

The structure and functioning of the brain are lateralized-the right hemisphere processes unexpected stimuli and controls spontaneous behavior, while the left deals with familiar stimuli and routine responses. Hemispheric dominance, the predisposition of an individual using one hemisphere over the other, may lead to behavioral differences; particularly, an individual may be programed to act in a certain way concerning hemispheric dominance. Hand preference is a robust estimator of hemispheric dominance in primates, as each hemisphere controls the opposing side of the body. Studies have found links between hand preference and the exhibition of behaviors in contexts such as exploring and manipulating objects. However, little is known whether hand preference predicts behavioral variations in other ecologically relevant contexts like predation. We investigated the relationship between hand preference and behavioral responses to two types of predator models in captive Barbary macaques (Macaca sylvanus) (n = 22). Besides, a nonpredator novel object was included as control. We found 91% of the macaques to be lateralized with no group-level bias. A higher rate of tension and focus (behavioral response) behavior was found in predator contexts than in the novel object condition. Unlike their right-hand counterparts, individuals with a strong left-hand preference elicited frequent focus and tension behavior toward the predator models. Additionally, the behavioral response varied with predator type. We also found an interaction effect between hand preference and predator type. Our study suggests that hand preference can reliably predict behavioral variations in the context of potential predation. While these results are consistent with lateralized brain function, indicating lateralization a neural mechanism of behavioral variation, the interaction effect between hand preference and predator type elucidates the importance of context-specificity when investigating laterality noninvasively. Future research on other nonhuman primates using the current framework may provide insights into the evolution of laterality and underlying behavioral predispositions.

Prosociality in a despotic society.

Prosociality is the intent to improve others' well-being. Existing hypotheses postulate that enhanced social tolerance and inter-individual dependence may facilitate prosocial preferences, which may favor the evolution of altruism. While most studies are restricted to "tolerant" (cooperatively breeding and self-domesticated) species, despotic societies provide an alternative opportunity to investigate prosociality due to nepotism and ample inter-individual dependencies. Japanese macaques live in hierarchical matrilineal societies, with strong kin bonds. Besides, tolerance among non-kin may persist through reciprocity. Using a group service food-provision paradigm, we found prosocial preferences in a semi free-ranging group of Japanese macaques. The extent of provisioning was at levels comparable to tolerant species. Dyadic tolerance predicted the likelihood and magnitude of provisioning, while kinship predicted the magnitude. We emphasize the role of a complex socio-ecology fostering individual prosocial tendencies through kinship and tolerance. These findings necessitate a framework including different forms of interdependence beyond the generally tolerant species.

Personality as a Predictor of Time-Activity Budget in Lion-Tailed Macaques (Macaca silenus).

Time-activity budget, i.e., how a population or an individual divides their day into various behaviours and activities, is an important ecological aspect. Existing research primarily focused on group-level time-activity budgets, while individual variations have only been reported recently. However, little is known about how consistent inter-individual differences or personalities influence time-activity budgets. We examined the personalities of lion-tailed macaques (Macaca silenus) and investigated their influence on individual time-activity budgets. The resulting personality traits, namely persistence, sociability, affiliation, and anxiety, were used to predict the three broad categories of the time-activity budget-food-related, active, and resting behaviours. We found that persistence and sociability positively predicted the time spent being active. Food-related behaviours were positively predicted by persistence, while anxiety was found to influence them negatively. The time spent resting was negatively predicted by persistence. We did not find an effect of affiliation on the time-activity budgets. We discuss these findings in light of the ecology of lion-tailed macaques. Our study highlights the importance of a novel approach that uses animal personality traits as predictors of individual time-activity budgets and offers insights regarding the use of personality assessments in conservation and welfare activities.

Adjustment in the point-following behaviour of free-ranging dogs - roles of social petting and informative-deceptive nature of cues.

Animals of different taxa can read and respond to various human communicative signals. Such a mechanism facilitates animals to acquire social information and helps them react in a context-dependent manner. Dogs have garnered extensive attention owing to their socio-cognitive skills and remarkable sensitivity to human social cues. For example, dogs readily respond to different human pointing gestures to locate hidden food rewards. However, a general inclination towards testing highly socialized pet dogs has resulted in a dearth of information on other sub-populations of dogs. Free-ranging dogs are one of the least socialized dog populations yet exhibit point-following behaviour flexibly. As a consequence of frequent negative interspecific interactions, they are typically wary of unfamiliar humans; thus, contextual recognition of human actions is paramount for these dogs to avoid potential conflict. However, the mechanisms influencing their point-following behaviour remain unidentified. We asked to what extent the informative-deceptive nature of cues and positive human interactions influence the interspecific communicative behaviour of these minimally socialized dogs. Using a point-following experiment with a 2 × 2 design, we focused on adult free-ranging dogs' behavioural adjustments. Dogs were randomly divided into two groups, with only one receiving brief social petting. Further, informative and deceptive cues were given to separate subsets within each group. Our findings suggest that brief social petting strongly affects the likelihood of free-ranging dogs' point-following tendencies. Dogs who received petting followed the pointing cues regardless of their informative or deceptive nature, whereas dogs who did not receive petting discriminated between informative and deceptive pointing. This study highlights the contribution of positive human interaction and informative-deceptive quality of cues in modulating the behavioural responses of free-ranging dogs in an interspecific communicative context.

Sociability of Indian free-ranging dogs (Canis lupus familiaris) varies with human movement in urban areas.

Cohabiting with humans in the same ecological space requires significant variation in the behavioral repertoire of animals. Behavioral variation can potentially improve the chances of survival of an individual. The influence of humans can be measured by quantifying specific behavioral parameters of the interacting individuals. Sociability or the tendency to be friendly toward others is one of many personality traits in animals that can provide us with insights regarding their relationship with humans. Free-ranging dogs are one of the successful urban-adapted species that interact with humans regularly, which, in turn, influences their behavioral properties. In this study, we tested 600 adult dogs from 60 sites across India, categorized as high, low, and intermediate human flux zones, to understand their degree of sociability toward an unfamiliar human. Initially, a "positive vocalization phase" was carried out. Unresponsive dogs were further tested in a "stimulus phase." The first phase was characterized by positive vocal sounds, while the second one included both food and positive vocalization. In addition, we surveyed a total of 1,200 people from the 60 sites to understand their perception of free-ranging dogs. Dogs in the IF zones were highly sociable compared to the other zones. High human flux zone dogs were reluctant to approach initially but showed an increased approach when food was provided. Low human flux zone dogs were the least sociable, and even the food reward had minimal impact on them. Our study provides the first evidence of behavioral variation in the degree of sociability of free-ranging dogs in urban environments. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Humans Dominate the Social Interaction Networks of Urban Free-Ranging Dogs in India.

Research on human-animal interaction has skyrocketed in the last decade. Rapid urbanization has led scientists to investigate its impact on several species living in the vicinity of humans. Domesticated dogs (Canis lupus familiaris) are one such species that interact with humans and are also called man's best friend. However, when it comes to the free-ranging population of dogs, interactions become quite complicated. Unfortunately, studies regarding free-ranging dog-human interactions are limited even though the majority of the world's dog population is free-ranging. In this study, we observed twelve groups of free-ranging dogs in their natural habitat, the streets. We quantified their interactions at the intra (dog-dog) and interspecific (dog-human) levels. The study areas were divided into two zones, namely - intermediate and high flux, based on human activity or movement. Social network analysis revealed higher instances of interspecific than intraspecific interactions, irrespective of the human flux zones. Humans, in significantly higher occasions, initiated both positive and negative behaviors in comparison to dogs. Our findings conclude that humans are a crucial part of the interaction network of Indian free-ranging dogs.

The effects of human attentional state on canine gazing behaviour: a comparison of free-ranging, shelter, and pet dogs.

The ability of animals to communicate using gaze is a rich area of research. How domestic dogs (Canis lupus familiaris) use and respond to the gaze of humans is an area of particular interest. This study examined how three groups of domestic dogs from different populations (free-ranging dogs, pet dogs, and shelter dogs) responded to a human during three attentional state conditions: when the human was making eye contact (attentive), when the human was turned away (inattentive), and when the human exited the testing area. We found that dogs from different populations differed in their gazing behaviour. Free-ranging dogs responded to the human's change in attentional state by looking significantly less at the human in the inattentive condition compared to the attentive condition. Pet and shelter dogs did not differ in their gazing behaviour between these conditions. However, they gazed significantly more at the human in both the inattentive and attentive conditions compared to the free-ranging dogs and also spent more time in the proximity of the experimenter. This study suggests that life experience plays an important role in how dogs respond to the attentional state of a human.

Free-Ranging Dogs Are Capable of Utilizing Complex Human Pointing Cues.

Dogs are one of the most common species to be found as pets and have been subjects of human curiosity, leading to extensive research on their socialization with humans. One of the dominant themes in dog cognition pertains to their capacity for understanding and responding to human referential gestures. The remarkable sociocognitive skills of pet dogs, while interacting with humans, is quite well established. However, studies regarding the free-ranging subpopulations are greatly lacking. The interactions of these dogs with humans are quite complex and multidimensional. For the first time, we tested 160 adult free-ranging dogs to understand their ability to follow relatively complex human referential gestures using dynamic and momentary distal pointing cues. We found that these dogs are capable of following distal pointing cues from humans to locate hidden food rewards. However, approximately half of the population tested showed a lack of tendency to participate even after successful familiarization with the experimental setup. A closer inspection revealed that anxious behavioral states of the individuals were responsible for such an outcome. Finally, we compared the results using data from an earlier study with dynamic proximal cues. We found that free-ranging dogs follow distal cues more accurately compared to proximal cue. We assume that life experiences with humans probably shape personalities of free-ranging dogs, which in turn influence their responsiveness to human communicative gestures.

Free-ranging dogs prefer petting over food in repeated interactions with unfamiliar humans.

Dogs (Canis lupus familiaris) are the first species to have been domesticated and, unlike other domesticated species, they have developed a special bond with their owners. The ability to respond to human gestures and language, and the hypersocial behaviours of dogs are considered key factors that have led them to become man's best friend. Free-ranging dogs provide an excellent model system for understanding the dog-human relationship in various social contexts. In India, free-ranging dogs occur in all possible human habitations. They scavenge among garbage, beg for food from humans, give birth in dens close to human habitations, and establish social bonds with people. However, there is ample dog-human conflict on the streets, leading to morbidity and mortality of dogs. Hence, the ability to assess an unfamiliar human before establishing physical contact could be adaptive for dogs, especially in the urban environment. We tested a total of 103 adult dogs to investigate their response to immediate social and long-term food and social rewards. The dogs were provided a choice of obtaining food either from an experimenter's hand or the ground. The dogs avoided making physical contact with the unfamiliar human. While immediate social reward was not effective in changing this response, the long-term test showed a strong effect of social contact. Our results revealed that these dogs tend to build trust based on affection, not food. This study provides significant insights into the dynamics of dog-human interactions on the streets and subsequent changes in behaviour of dogs through the process of learning.

Free-ranging dogs show age related plasticity in their ability to follow human pointing.

Differences in pet dogs' and captive wolves' ability to follow human communicative intents have led to the proposition of several hypotheses regarding the possession and development of social cognitive skills in dogs. It is possible that the social cognitive abilities of pet dogs are induced by indirect conditioning through living with humans, and studying free-ranging dogs can provide deeper insights into differentiating between innate abilities and conditioning in dogs. Free-ranging dogs are mostly scavengers, indirectly depending on humans for their sustenance. Humans can act both as food providers and as threats to these dogs, and thus understanding human gestures can be a survival need for the free-ranging dogs. We tested the responsiveness of such dogs in urban areas toward simple human pointing cues using dynamic proximal points. Our experiment showed that pups readily follow proximal pointing and exhibit weaker avoidance to humans, but stop doing so at the later stages of development. While juveniles showed frequent and prolonged gaze alternations, only adults adjusted their behaviour based on the reliability of the human experimenter after being rewarded. Thus free-ranging dogs show a tendency to respond to human pointing gestures, with a certain level of behavioural plasticity that allows learning from ontogenic experience.

Practice makes perfect: familiarity of task determines success in solvable tasks for free-ranging dogs (Canis lupus familiaris).

Domestic dogs' (Canis lupus familiaris) socio-cognitive faculties have made them highly sensitive to human social cues. While dogs often excel at understanding human communicative gestures, they perform comparatively poorly in problem-solving and physical reasoning tasks. This difference in their behaviour could be due to the lifestyle and intense socialization, where problem solving and physical cognition are less important than social cognition. Free-ranging dogs live in human-dominated environments, not under human supervision and are less socialized. Being scavengers, they often encounter challenges where problem solving is required in order to get access to food. We tested Indian street dogs in familiar and unfamiliar independent solvable tasks and quantified their persistence and dependence on a novel human experimenter, in addition to their success in solving a task. Our results indicate that free-ranging dogs succeeded and persisted more in the familiar task as compared to the unfamiliar one. They showed negligible amount of human dependence in the familiar task, but showed prolonged gazing and considerable begging behaviour to the human experimenter in the context of the unfamiliar task. Cognitive abilities of free-ranging dogs thus play a pivotal role in determining task-associated behaviours based on familiarity. In addition to that, these dogs inherently tend to socialize with and depend on humans, even if they are strangers. Our results also illustrate free-ranging dogs' low competence at physical cognitive tasks.

Differences in problem-solving between canid populations: Do domestication and lifetime experience affect persistence?

Past research has suggested that a variety of factors, phylogenetic and ontogenetic, play a role in how canines behave during problem-solving tasks and the degree to which the presence of a human influences their problem-solving behaviour. While comparisons between socialized wolves and domestic dogs have commonly been used to tease apart these predictive factors, in many cases a single dog population, often pets, have been used for these comparisons. Less is understood about how different populations of dogs may behave when compared with wolves, or with each other, during an independent problem-solving task. This experiment compared the independent persistence of four populations of canines (two groups of pet domestic dogs, a group of free-ranging domestic dogs, and human-socialized wolves) on an independent problem-solving task in the presence of an on looking human. Results showed that wolves persisted the most at the task while free-ranging dogs persisted the least. Free-ranging dogs gazed at the human experimenter for the longest durations during the task. While further research is needed to understand why these differences exist, this study demonstrates that dogs, even those living outside human homes as scavengers, show comparatively low levels of persistence when confronted with a solvable task in the presence of a human as well as significantly greater duration of human-directed gaze when compared with wolves.