Understanding the urban adaptations of free-ranging dogs (Canis lupus familiaris) in India

Bhattacharjee, Debottam (2020) Understanding the urban adaptations of free-ranging dogs (Canis lupus familiaris) in India. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Debottam Bhattacharjee (14RS053)) 14RS053.pdf - Submitted Version Restricted to Repository staff only Download (3MB)

Abstract

Co-habiting with humans in an urban ecological space requires adequate variation in a species’ behavioural repertoire. The eco-ethology of many urban species have been shown to be modified due to human activities leading to urban adaptations. Dogs (Canis lupus familiaris) are the first species to have been domesticated and have a long evolutionary history of co-habitation with humans. In the last two decades, scientists have investigated various questions on dogs pertaining to its domestication. In fact, no other species belonging to the family Canidae has received such attention in the scientific world. Unfortunately, majority of the work was confined to pet dogs in the western countries. Pet dogs are the result of artificial breeding based on desirable traits and their activities are typically determined by their owners. Free-ranging dogs found in most of the developing countries, on the other hand, represent a naturally breeding population without direct human supervision. Studying free-ranging dogs can thus provide us with crucial insights on the ecology and evolution of dogs in greater detail. Close to 80% of the world’s dog population is free-ranging, yet scientific studies on them are almost non-existent. Scientists have realised the importance and need of studying these dogs very recently to address various facets of the much debated domestication event. Free-ranging dogs are a highly successful urban-adapted species living in all possible human habitats in the developing countries. The dog-human relationship is highly complex and possess multiple trajectories. For example, these dogs depend on human subsidized food, choose dens near human households, yet receive a range of negative stimuli from humans; mortality of these dogs is mostly influenced by humans. In this thesis, we tried to answer questions relating to the dog-human relationship on Indian streets. My thesis involved an interdisciplinary approach where behavioural, cognitive, and ecological aspects are discussed to shed light on the evolution of the dog-human relationship. We began the work by looking at the natural history of free-ranging dogs in India. We collected data on the abundance of dogs and the distribution of their potential food resources, across India. Moreover, we recorded the sex ratio, group size, and behaviours of dogs at different study locations. We characterized study areas with regard to human activity levels by estimating human flux or movement and categorised them into low, intermediate and high flux zones. Our findings clearly suggested varying distribution of dogs and their food resources across different microhabitats in India. While a direct effect of food resource was not found, human flux significantly predicted the distribution of dogs. Moreover, we found a strong impact of changing human flux on the abundance and behavioural activity of free-ranging dogs. In the next section, we investigated the intra-group dynamics of dogs from the perspective of long-debated dominance-rank relationships. We looked at the steepness and linearity of agonistic and formal dominance hierarchies of groups of dogs from intermediate and high human flux zones. Our study did not reveal any clear dominance hierarchy among the free-ranging dogs, either in the intermediate or high human flux zones. The overall frequencies of interactions between the group members were found to be quite low, with many unknown interactions between for several dyads. We also proposed the use of subtle behavioural cues to maintain hierarchy rather than showing frequent behavioural exchanges in dogs. Findings from the study further led us to test free-ranging dogs’ interactions with humans. We found that these dogs interact with humans more compared to their conspecifics. Interestingly, we noticed that dogs rarely initiated behaviours towards humans, while humans played the predominant role in initiating both positive and negative behaviours towards dogs. We concluded that humans are a predominant part of the interaction network of the Indian free-ranging dogs. This opened up a window of testing dogs’ physical and social cognitive abilities. We found that free-ranging dogs lack the ability to persist on physical cognitive tasks and are poor performers like pet dogs. A higher dependence on humans is thought to be a key factor restricting dogs from persisting on an unfamiliar task. Interestingly, free-ranging dogs, as scavengers, showed competence while solving a familiar task, though task difficulty remained a factor that could not be disentangled. A partial dependence on humans was assumed to be the outcome of their long-history of co-evolution which resulted in a reduced problem-solving capacity in dogs. Surprisingly, a role of social facilitation was observed which predicted improved performances in both familiar and unfamiliar tasks. Free-ranging dogs like any other urban species are typically found to be aversive towards making direct physical contact with unfamiliar humans. The sociability of dogs was found to correlate with human flux, suggesting a role of life experience in shaping the personalities of these dogs. Dogs were shown to understand different human social cues and respond accordingly. The dogs in groups were bolder while responding to threatening cues from humans than in the solitary condition. Using two studies, we showed their ability to understand human pointing gestures, both simple and complex. The behavioural states of the dogs were heavily found to influence their responses towards humans. Dogs were found to be anxious or fearful while encountering an unfamiliar human. Interestingly, we found a crucial role of positive socialization in the form of petting in modifying such behavioural states of dogs and further building a strong dog-human relationship. In summary, this thesis provides unprecedented inputs into the current understanding of the evolution of dog-human relationship. The findings are not only restricted to the scientific advancement but may also be helpful in mitigating the growing doghuman conflict on the streets in India, by enhancing an understanding of the dynamics of the relationship between the two species, that might enable better management strategies.

Actions (login required)

View Item