Biological anthropologists have studied the positive benefits of owning a pet animal in the United States. One research group recruited participants from a population of reproductive-aged women living in an urban area. The researchers collected saliva samples from participants before and after they interacted with their pet cat. Stress hormone levels were measured from the samples to determine if interacting with a cat lowered or decreased their stress levels. Results showed that participants who described a strong attachment to their pet cat had lower levels of stress hormone after interacting with their cat.