What Dogs Can Teach Us About Global Challenges
Our planet and its resources are finite. We are placing ever-increasing demands on those resources, straining the capacity of our environment. Increasing human populations are associated with the need for more food and increases in urbanization, globalization, inequality, conflict, environmental damage, and climate change. We must find ways to reduce these pressures. To that end, the authors of this case study suggest an interdisciplinary approach that brings together scientists from diverse fields with varying expertise, experience, and viewpoints. As an example, the authors develop a comprehensive assessment of the long-term relationship between humans and dogs that provides insights to help overcome some of our global challenges.
No other animal has a closer relationship with humans than the dog. We’ve shared lives, diets, microbiomes, and pathogens. Canis familiaris, the modern dog, was first domesticated from Eurasian gray wolves, Dogs and humans have co-evolved over millennia, lives and stories intertwining. Along with hunter-gatherers across five continents, each species benefited from the other’s successes. Now mostly kept as companions, dogs have extended their relationships with humans. Some societies view dogs as deities while in others they are food or vermin. They can detect disease, guide the blind, provide emotional and physical support, and aid law enforcement in a variety of roles. There are an estimated 700 million to one billion dogs across the globe. Dog density varies across continents and countries, with the highest concentrations in the Americas, Australia, and parts of Europe.
Unfortunately, the rise of the domestic dog has also had negative consequences. The extirpation of the gray wolf in certain regions may be linked to increasing populations of dogs. Canine distemper has killed off most of the wild African dogs. Rabies from dogs has killed up to 75% of the Ethiopian wolf population. Dogs come into conflict with coyotes in the United States. In Australia and New Zealand, they are charged with the decline or extinction of many vertebrate fauna. Dogs are affecting the biodiversity on many Caribbean islands. All of that said, dogs have also aided humans in conservation efforts with their keen sense of smell. They can locate populations of animals that people cannot detect. Birds such as the spotted and barred owls, reptiles such as the gecko, and mammals such as the bobcat and lowland gorilla have all benefited from trained dogs’ noses. They can also locate invasive species that can then be removed (hopefully humanely).
Dogs impact our environment in other ways as well. What we choose to feed our dogs has potentially negative consequences. The demand for fish in companion animal food is driving the depletion of Pelagic fish stocks. Food grown on land requires large amounts of land, water, and fossil fuels. In the U.S., dogs and cats contribute an estimated 64 million tons of greenhouse gases, equivalent to 25-30% of the impact from humans. In China, dogs and cats use resources equivalent to 70-245 million people. With companion animal populations on the rise in developing countries, their needs will further strain food security and environmental health. Since roughly one in eight people in the world are malnourished, this raises an ethical dilemma when we feed quality protein to dogs and cats that could otherwise go to humans.
Dogs share more known pathogens with humans than any other domesticated species. This is not surprising given how long dogs and humans have cohabited. Dogs host roughly 30 diseases and parasites transmissible to humans. Rabies seems to appear in documents from the Middle East dated to 2300 BCE and may have appeared in Europe around 500 BCE; it remains a danger for both dogs and humans in India and many regions of Asia and Africa. Perhaps 50% of the global dog population is free breeding, even if owned, and represents the primary rabies threat. Dog bites, whether rabid or not, also present a significant public health threat all over the world. And of course, most of us who are guardians of dogs are familiar with another disease risk posed by dogs—feces. So-called “poop scoop” laws are now the standard approach to the problem of canine excrement hygiene. These laws reduce the risk of spreading disease or parasites both to humans and to other dogs.
Dogs suffer many of the same diseases as humans, including cancers, epilepsy, arthritis, diabetes, and even psychiatric disorders. They also show age-related health declines similar to humans. The large size of the dog population means that genomic studies in dogs may provide useful information about disease risk factors for both dogs and humans. Indeed, companion animals of all types provide an opportunity to study the variety of factors, both biological and environmental, that affect disease risk and healthy aging. Longitudinal studies, which provide some of the most valuable insights, are very feasible where dogs are cared for in a single family throughout their lives.
This study offers an overview of the history, evolution, and breadth of human-dog relationships. Humans and dogs both have impacts on their societies and environments, and their co-existence creates a multiplier effect. Advocates can use this study to identify issues where conflicts may arise through a misalignment of objectives across disciplines. It also provides insights to help us find common interests that may create opportunities for shared advocacy efforts.