He has published over 300 papers throughout his career in top scientific journals.
Bob was especially known for his work in the conservation genetics of wild canids, which included species such as wolves, foxes, and coyotes. He was a pioneer in using DNA technology to study these groups, and his research shed light on the genetic basis of their behavior and evolution. His work also significantly impacted the conservation and management of canid species around the globe. Locally, his work on the effects of urbanization on carnivores in Los Angeles has received considerable media attention. In a 2006 study, using genetic data, Bob and his students showed that freeways are a barrier to migration of bobcats and coyotes, establishing the premise of wildlife tunnels to allow animal crossings.
In addition to his work on wild canids, Bob contributed significantly to our understanding of the origins of domestic dogs. His groundbreaking research using genomics helped shed light on their evolutionary history, and his findings have greatly impacted our understanding of the process of domestication.