Biology subjects

Bhadra, A.

Publications and source records attributed to Bhadra, A..

10 recordsLinked to original sources

bioRxiv2026

Fixed Players, Fluid Moves: Refining Strategy While Preserving Identity in Free-Ranging Dogs

Animals often display active decision-making while navigating noisy habitats, for varied purposes like foraging, finding shelter, evading predators or finding suitable mates. While some responses are hardwired, following fixed action patterns, others are more flexible, and display context-dependent plasticity. Animals might weigh behavioural consistency against adaptive plasticity when facing recurrent ecological difficulties, but the nuanced mechanisms orchestrating this balance is not well understood. We investigated this question by repeatedly exposing 47 free-ranging dogs to chicken contaminated with lemon solution, an aversive but edible and familiar food source, across four consecutive trials. By integrating behavioural frequencies, latency measures, feeding efficiency, interaction-time and location effects, repeatability analyses, and behavioural sequence structure, we examined how repeated experience influenced foraging behaviour. Contrary to expectations of broad behavioural reorganisation, most behaviours remained stable. Initial approach latency was strongly repeatable within individuals with no detectable influence of sex or trial number across the population. This suggests that how an animal first assesses risk is primarily shaped by stable personality traits rather than momentary external factors. Eating behaviour and bowl nudging also changed selectively across exposures, with modest sex differences in several behaviours. Behavioural sequences became increasingly similar over time, while several behaviours retained consistent individual differences, indicating persistent behavioural tendencies. Our results collectively demonstrated that repeated aversive exposure selectively modified a few critical decision points rather than the entire behavioural repertoire. This implies that animals can adapt by making small adjustments to specific behaviours while maintaining the stability of their overall behavioural architectures. Animals seem to assess risk separately from how well they use resources. That separation may help explain how stable personalities can coexist with the fast, flexible decisions animals need in unpredictable environments shaped by humans.

animal behavior and cognition↗

bioRxiv2026

Who rests with whom? Sex composition and group demography shape resting associations in free-ranging dogs

Free-ranging dogs frequently rest near conspecifics, but the demographic factors structuring their resting associations remain poorly understood. We quantified dyadic resting associations in 26 free-ranging dog groups in West Bengal, India, observed between 2019 and 2023. Association strength was estimated from scan based resting co-occurrences using the Half-Weight Index. We tested whether dyadic association strength varied with dyad sex composition, dyad life stage composition, group size, and group sex ratio using a generalised additive model for location, scale and shape that accounted for group identity and repeated occurrence of individuals across dyads. Male-male dyads had lower association strengths than female-female dyads, whereas mixed-sex dyads did not differ from female-female dyads. Association strength decreased with increasing group size but increased as the male-to-female ratio within the group increased, while life-stage composition had no detectable effect. Individual level network metrics, including strength, reach, clustering coefficient, affinity, and eigenvector centrality, did not vary with sex or season. Mixed-sex pairs were also frequently represented among the strongest dyadic associations within groups. These findings indicate that resting associations in free-ranging dogs vary with dyad sex composition and group demography. Further opportunity-controlled analyses are required to determine whether the prominence of mixed-sex dyads reflects preferential association rather than group composition alone.

animal behavior and cognition↗

bioRxiv2024

Ready, set, yellow! Color Preference of Indian Free-ranging Dogs

Most of the research on color vision related behaviors in dogs has involved training the dogs to perform visual discrimination tasks. We investigated the meaning of color to untrained Indian free-ranging dogs (FRDs). Using one-time multi-option choice tests for color preference in 134 adult dogs, we found the dogs to prefer yellow objects over blue or gray ones (p < 0.001, Cramers V = 0.433) while there was no preference between blue and gray (N = 102, p = 0.165). We next pitted a yellow object against a gray object that had food. Here, the dogs ignored the food to approach the yellow object first, both when the food was biscuit (N = 52, p < 0.001, Cramers V = 0.576) and chicken (N = 61, p < 0.001, Cramers V = 0.540), indicating the color preference to be quite strong. Color preference has previously been investigated in many other animals and has implications for behaviors like mate choice and foraging. Our study provides a new perspective into the ecology of Indian FRDs and might have implications for pet dogs as well, if they too show this preference. HighlightsO_LIIndian free-ranging dogs (FRDs) show preference toward the color yellow over blue and gray. C_LIO_LIIndian FRDs show no preference between blue and gray colors. C_LIO_LIAttraction towards a yellow object can be stronger than attraction towards food rewards for Indian FRDs. C_LI

animal behavior and cognition↗

bioRxiv2023

Does novelty influence foraging decision of a scavenger?

Acquiring knowledge about the environment is crucial for survival. Animals, often driven by their explorative tendencies, gather valuable information regarding food resources, shelter, mating partners, etc. While neophilia, or the preference for novel environmental stimuli or objects, can promote exploratory behaviour, neophobia, or avoidance of novel environmental stimuli, can constrain such behaviour. Neophobia can reduce predation risk, yet decreased exploratory behaviour resulting from it may limit the ability to discover potentially highly rewarding resources. Dogs (Canis familiaris) living in semi-urban and urban environments as free-ranging populations are, 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 pet and captive pack-living dogs are known to exhibit neophilia when provided with novel objects, little is known about free-ranging dogs behavioural responses to novel objects, particularly in foraging contexts. Using an object choice experiment, we tested 274 free-ranging dogs from two age classes, adult and juvenile, to investigate their object-neophobia in a scavenging context. We employed a betweensubject study design, providing dogs with a familiar and a potentially novel object, both baited with equal but (partially)hidden food rewards. Adult and juvenile dogs significantly inspected the novel object first compared to the familiar one, even when we reduced the visual obscurity of the familiar object, i.e., when the hidden food reward was partially visible. Furthermore, novel objects with varying strengths of olfactory cues (baited vs. false-baited) were inspected comparably by adults and juveniles. No significant differences were found in the latencies to inspect the objects. These results indicate that free-ranging dogs, evidently from an early ontogenic 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, yet selection for object-neophilia in semi-urban and urban-dwelling animals can guide foraging decision-making processes, providing adaptive benefits.

animal behavior and cognition↗

bioRxiv2022

Loss of function variants in DNAJB4 cause a myopathy with early respiratory failure

DNAJ/HSP40 co-chaperones are integral to the chaperone network, bind client proteins and recruit them to HSP70 for folding. We performed exome sequencing on patients with a presumed hereditary muscle disease and no genetic diagnosis. This identified four individuals from three unrelated families carrying an unreported homozygous stop gain (c.856A>T; p.Lys286Ter), or homozygous missense variants (c.74G>A; p.Arg25Gln and c.785T>C; p.Leu262Ser) in DNAJB4. Affected patients presented with axial rigidity and early respiratory failure requiring ventilator support between the 1st and 4th decade of life. Selective involvement of the semitendinosus and biceps femoris muscles was seen on MRI scans of the thigh. On biopsy, muscle was myopathic with angular fibers, protein inclusions and occasional rimmed vacuoles. DNAJB4 normally localizes to the Z-disc and was absent from muscle and fibroblasts of affected patients supporting a loss of function. Functional studies confirmed that the p.Lys286Ter and p.Leu262Ser mutant proteins are rapidly degraded in cells. In contrast, the p.Arg25Gln mutant protein is stable but failed to complement for DNAJB function in yeast, disaggregate client proteins or protect from heat shock induced cell death consistent with its loss of function. DNAJB4 knockout mice had muscle weakness and fiber atrophy with prominent diaphragm involvement and kyphosis. DNAJB4 knockout muscle and myotubes had myofibrillar disorganization and accumulated Z-disc proteins and protein chaperones. These data demonstrate a novel chaperonopathy associated with DNAJB4 causing a myopathy with early respiratory failure. DNAJB4 loss of function variants may lead to the accumulation of DNAJB4 client proteins resulting in muscle dysfunction and degeneration.

genetics↗

bioRxiv2020

Inhibition of DNAJ-HSP70 interaction improves strength in muscular dystrophy

Dominant mutations in the HSP70 co-chaperone DNAJB6 cause a late onset muscle disease termed limb girdle muscular dystrophy type 1D (LGMD1D), which is characterized by protein aggregation and vacuolar myopathology. Disease mutations reside within the G/F domain of DNAJB6, but the molecular mechanisms underlying dysfunction are not well understood. Using yeast, cell culture, and mouse models of LGMD1D, we find that the toxicity associated with disease-associated DNAJB6 requires its interaction with HSP70, and that abrogating this interaction genetically or with small molecules is protective. In skeletal muscle, DNAJB6 localizes to the Z-disc with HSP70. Whereas HSP70 normally diffuses rapidly between the Z-disc and sarcoplasm, the rate of HSP70s diffusion in LGMD1D mouse muscle is diminished likely because it has an unusual affinity for the Z-disc and mutant DNAJB6. Treating LGMD1D mice with a small molecule inhibitor of the DNAJ-HSP70 complex re-mobilizes HSP70, improves strength and corrects myopathology. These data support a model in which LGMD1D mutations in DNAJB6 are a gain-of-function disease that is, counter-intuitively, mediated via HSP70 binding. Thus, therapeutic approaches targeting HSP70:DNAJB6 may be effective in treating this inherited muscular dystrophy.

cell biology↗

bioRxiv2019

\"Bolder\" together - response to human social cues in free-ranging dogs

Interspecific interactions within an ecosystem have different direct and indirect effects on the two interacting species. In the urban environment, humans are a part of an interaction network of several species. While indirect human influence on different urban species has been measured extensively, experimental studies concerning direct human influence are lacking. In this study, we tested interactions between groups of urban free-ranging dogs (Canis lupus familiaris) and solitary unfamiliar humans in ecologically relevant contexts. We provided different sets of dogs with four commonly used human social cues (neutral, friendly, low and high impact threatening) to understand their responses at the group-level and identify potential inter-individual differences. Finally, we compared data from a previous study to investigate the differences in behavioural outcomes between solitary and groups of dogs while interacting with humans. The study not only strengthens the idea of situation-relevant responsiveness in free-ranging dogs but also highlights the minute differences between solitary and group-level reactions in the form of higher approach and less anxious behaviour of groups towards the unfamiliar human. Additionally, we report inter-individual differences and the effect of sex while responding to the threatening cues. Our study suggests a direct benefit of group-living over a solitary lifestyle in free-ranging dogs while interacting with humans in the streets.\n\nSummary statementFree-ranging dogs can benefit by living in groups over a solitary lifestyle while interacting with unfamiliar humans in urban habitats irrespective of having significant inter-individual differences.

animal behavior and cognition↗

bioRxiv2019

Free-ranging dogs are capable of comprehending complex human pointing cues.

Dogs are 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 of understanding and responding to human referential gestures. The remarkable socio-cognitive skills of pet dogs, while interacting with humans, is quite well established. However, studies regarding the free-ranging subpopulations are greatly lacking. Free-ranging dogs represent an ideal system to investigate interspecific communication with unfamiliar humans, nullifying any contribution of indirect conditioning. The interactions of these dogs with humans are quite complex and multidimensional. For the first time, we tested free-ranging dogs ability to understand relatively complex human referential gestures using dynamic and momentary distal pointing cues. We found that these dogs are capable of apprehending distal pointing cues from humans. However, approximately half of the population tested showed a lack of tendency to participate even after successful familiarization with the experimental set-up. A closer inspection revealed anxious behavioural states of the individuals were responsible for such an outcome. We assume that life experiences with humans probably shape personalities of free-ranging dogs, which in turn influence their responsiveness to human communicative gestures.

animal behavior and cognition↗

bioRxiv2019

Cooperation only for high rewards - a solvable task-based study on free-ranging dogs

The benefits of group living mostly surpass the disadvantages like sharing of resources and competition over food, space and mates, driving the evolution of social organization. Group living can be facilitated by social tolerance and cooperation among the group members. Social canids (e.g. wolves) display cooperative breeding, hunting, and prosocial activities in different contexts. Unlike cooperative pack-living wolves (Canis lupus lupus), their descendants, domesticated dogs (Canis lupus familiaris), show varying levels of associations from solitary to stable social groups. Free-ranging dogs are group-living but prefer to forage solitarily, hence providing an excellent opportunity for investigating social tolerance and coordinated task performance among the members in various situations. We tested 113 adult-only groups of free-ranging dogs in three different tasks to investigate group responses and performance in problem-solving situations in the presence of an unfamiliar human. Task 1 (unfamiliar, single food reward) and 2 (familiar, single food reward) examined group responses and cooperation from the perspective of familiarity, while Task 3 (familiar, multiple food rewards) enabled us to test whether increased food rewards promote social tolerance and food sharing among the group members. Regardless of significantly higher performance in Task 2 compared to Task 1, cooperation and food sharing were significantly lower in both. Task 3 revealed a strong positive correlation between food sharing and social tolerance, but not between success and social tolerance, suggesting a tendency for cooperation. We conclude that context-dependent cooperation and tolerance among group members facilitate group-living in free-ranging dogs.\n\nSignificance statementGroup living is a common phenomenon in the animal world where the members of a group show social tolerance and co-operative behaviours towards each other. This need for cooperative intents increases manifolds while groups face different problem-solving situations in their day to day lives. Here, we tested a large number of free-ranging dog groups to understand general cooperative intents such as social tolerance and food sharing in different problem-solving conditions. We found shreds of evidence of context-dependent cooperation and social tolerance among group members with minimal display of aggression. It is not adaptive for the dogs to fight or display aggression over resources. Alternatively, use of subtle cues such as display of dominance and subordination seem to be more plausible mechanisms for the development of efficient scavenging strategies and maintaining hierarchy.

animal behavior and cognition↗

bioRxiv2018

Free-ranging dogs understand human intentions and adjust their behavioral responses accordingly

Domestic dogs (Canis lupus familiaris) are remarkably sensitive and responsive while interacting with humans. Pet dogs are known to have social skills and abilities to display situation-specific responses, but there is lack of information regarding free-ranging dogs which constitute majority of the worlds dog population. Free-ranging dogs found in most of the developing countries interact constantly with familiar and unfamiliar humans receiving both positive and negative behavior. Thus, understanding human intentions and subsequent behavioral adjustments are crucial for dogs that share habitats with humans. Here we subjected free-ranging dogs to different human social communicative cues (friendly and threatening - low and high), followed by a food provisioning phase and tested their responsiveness. Dogs exhibited higher proximity seeking behavior as a reaction to friendly gesture whereas, they were prompted to maintain distance depending on the impact of the threatening cues. Interestingly, only the high-impact threatening showed to have a persistent effect which also remained during the subsequent food provisioning phase. An elevated approach in the food provisioning phase elicited the dependency of free-ranging dogs on humans for sustenance. Our findings suggest that free-ranging dogs demonstrate behavioral plasticity on interacting with humans; which provides significant insights into the establishment of the dog-human relationship on streets.

animal behavior and cognition↗