An estimated 70 million feral cats live in the United States alone - decimating bird populations and threatening public health. This informative book investigates the growing populations of "obligates" - abandoned pets, now wild and producing feral offspring, and introduced animals that live in urban and urban fringe areas. An examination reveals the impact these animals are having on resources, space, and native species. Additional content focuses on the charities and organizations that help care for and limit the numbers of feral animals.