Considering the long history of human-animal relationships, concern about the status of homeless cats and dogs constitutes a recent development. Animal shelters have existed in the United States for only about 150 years. We'll be examining the social and cultural significance of animal sheltering. From this perspective, the institution of sheltering highlights the position of animals, an intricate relationship between public policy and private morality. Although people often use the term shelter and pound synonymously, they originated from different responses to unwanted animals. More precisely, they reflected the changing status of companion animals, and attitude toward their appropriate treatment. I'll use the term shelter except where pound is historically accurate. Today when it comes to the treatment of animals, it's not the name of the facility that matters, but the attitudes of the people who run it, and those who live in the surrounding community. Animals could receive harsh or humane treatment at either kind of place. In general, pounds usually come under the auspices of municipal governments. But to complicate matters further, a city or town might call its animal control facility a shelter. Alternatively, a city or town might not operate a dedicated animal control facility, but through a contractual arrangement would house animals at a privately run shelter. The options hint at the various means whereby communities respond to problems involving stray, injured, or aggressive animals. Some have departments or agencies dedicated to animal control. Others provide animal-related services through police departments or other arms of the government. In most cases, funding for government operated facilities comes largely, although not exclusively, from fees for dog licensing, redemption or adoption of animals, and fines for animal control violations. Moreover, a humane society, or a group dedicated to the prevention of animal cruelty, might also operate a shelter. To make it even more confusing, some organizations, such as the Humane Society of the United States and the American Humane Association, don't run shelters at all but focus on animal advocacy. Often established as non-profit organizations, animal shelters might exist solely through donations, or they might receive partial funding from a local government in exchange for providing shelter services. In large cities, one might find a municipally run shelter as well as one or more shelters operated by private non-profit organizations. The practice of sheltering stray animals originated in the livestock impounds of colonial American towns. At the time, owners commonly turned their livestock out to graze, thus feeding them at no cost. The animals quite naturally wandered. When residents' cattle, horses, hogs, or other animals roamed freely, they often left damage in their wake. The first American animal control regulation passed in New Amsterdam in 1648 required the confinement of hogs to keep them from damaging the streets by rooting. Subsequent measures required the capture and impound of free roaming livestock in a walled or fenced-in corral. Owners could identify and reclaim their animals for a fee, which provided an income for the pound master. He could keep unclaimed livestock for sale or for personal use. In the example of the colonial impounds, we see the first efforts at animal control. Note that it targeted livestock, not companion animals. A dog might have occasionally caused sufficient public nuisance to end up in the impound, but no cats would've landed there. Before the 1800s, neither dogs nor cats had the value as purely companions that they've attained today. This isn't to say that people felt no affection toward animals. History offers numerous examples of close relationships. Rather, it means that animals played primarily instrumental roles. They contributed to the economies of human communities by working in households, farms, and stables. They hunted, herded, and kept watch. They roamed freely and usually lived outdoors or with minimal shelter. They also bred freely, which meant that anyone wishing to have a dog or a cat could easily acquire one. An owner might reclaim a valued hunting dog from the pound, but in general, because dogs and cats had no economic value, pound masters would simply kill the unclaimed ones. Gradually, people's attitude toward this means of solving the problem of animals would change. The modern animal shelter would emerge in response. Because the approximately 5,000 animal shelters currently operating in the United States function independently, generalizable research presents a challenge. But regional studies, as well as studies of individual facilities, have examined several issues that are salient for sheltering overall. I'll highlight a few of these. One primary concern involves understanding intake, or how animals enter the shelter system. Consequently, a large body of research has analyzed the reasons that owners give for relinquishing their pets. Because adoption rates represent another important issue, studies have also analyzed people's decisions to adopt shelter animals, and the factors that make adoption successful. Another major concern has to do with the health and welfare of animals housed in shelters. This has involved research on topics relating to infectious disease management, animal abuse, and sterilization programs. Without question, the practice of killing healthy, unwanted animals constitutes the most important issue in animal sheltering today, and the rise of no-kill shelters represents a profound, if controversial, response. Because shelters use the term euthanasia, which means intentionally ending a life to alleviate suffering, I'll also use it. However, most of the animals who die in shelters don't require euthanasia in the true sense. Although no definitive statistics enumerate the total killed annually, conservative estimates put it at just under three million, making shelters the leading cause of death for companion animals in the United States. The issue of killing healthy but unwanted animals sparked the creation of the first humane shelters and continues to shape shelter policies today.