Understanding Scavenging Behavior and Factors Affecting Scavenging Efficiency in Free-ranging Dogs

Deheria, Jayshree (2015) Understanding Scavenging Behavior and Factors Affecting Scavenging Efficiency in Free-ranging Dogs. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Jayshree Deheria (10MS90)) MS_Thesis_Jayshree.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Dogs (Canis lupus familiaris) have descended from wild grey wolves and have adapted to as scavenging lifestyle in the wild. Free-ranging dogs are scavengers living on human cast-offs and handouts, and they rarely hunt. How efficient are they as scavengers? Earlier work from our lab shows that they mostly tend to forage alone, which is a good strategy for scavenging, but they change this strategy based on social conditions. My work focused on understanding their efficiency as scavengers using a three-pronged approach. Resource dispersion hypothesis (RDH) states that if the key trophic resources are patchily distributed then individuals would form groups and create minimum territories with sharing or no cost in terms of competition for food. I carried out a population level study to estimate the population structure of dogs and to understand the distribution of resources and dog groups in time and space. The second part of my work comprised of behavioral observations of dogs on the IISER Kolkata Campus at Mohanpur to understand their foraging behavior, and to map the resources they exploit. This formed the basis for an experiment in which we created new resources to see if the existing groups can be manipulated, as predicted by RDH. Our experiments suggest that creation of new resources is likely to lead to territory expansion, rather than group splitting in the dogs, at least on a short time scale. Thus their social groups are quite stable, not prone to fission by local perturbations. Efficient scavenging not only requires the capability to forage alone, but also the capability of finding food from difficult locations, and hence some problem solving ability. I checked the scavenging efficiency of the dogs when faced with inaccessible food in varying levels of difficulty. The dogs were highly successful when provided with a relatively easy and known task, but were much less successful when faced with a novel and more difficult task. However, comparing out results with those known from pet dogs suggest that the free-ranging dogs are better than pets at problem solving. My work suggests that the problem solving ability of free-ranging dogs, in combination with the plasticity of their social behavior which helps them to maintain stable groups while allowing for high foraging efficiency, have enabled the free-ranging dogs to survive efficiently in the human dominated environment as scavengers.

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