Effects of nutrition choices and lifestyle changes on the well-being of cats, a carnivore that has moved indoors

Cats (Felis catus) are complicated creatures that have fascinated, frustrated, and even evoked fear in humans for millennia. Although many factors influence these emotions, most are certainly tied to the fact that humans have attempted to tame one of the world’s greatest hunters, with only modest success. Cats have lived at the periphery of human society, cohabiting with humans but still retaining their independence, with diet options that have included small animals or birds they captured. Cats in this role were often included as members of the family, but they only interacted with humans at times of their choosing and, in the process, maintained strong ties to their feral background. Today, of all companion animals, domestic cats retain the most anatomic, metabolic, and behavioral features of their predecessors. Domestication has changed cats relatively little. 1 However, cats have surpassed dogs as the most common household pet in American households, and even though they have been brought indoors and domesticated, their relationship with humans and their nutritional, physical, and emotional needs remain unique. 1–3 Cats have come to fill a niche that the current urban envi ronment demands because of their ability to live in small spaces, function on little input from their human caregivers, and coexist with humans in a busy society. Cats in confinement live under the authority of their owners, who control what, when, where, and how they eat and eliminate, and determine their opportunities to engage in species-typical activities. Animalowner relationships also are dyadic, so the actions of the owner influence the actions of the animal, which in turn influence subsequent actions of the owner on the basis of attitudes and beliefs that arise in the mind of the owner as a result of the animal’s actions. 4–6 Moreover, relationships change over time and are further influenced by other events in the owner’s and cat’s lives. Fortunately for cats, their current preeminence as pets has resulted in substantial improvements in their