The pet-health link has been well established for relationships with dogs, cats, birds, mammals, reptiles, aquarium fish and horses. A prominent researcher in this field also suggests that similar benefits may extend to individuals who care for their gardens, farmers actively tending their crops, 4-H children with pet animals, as well as bird watchers and wild bird feeders. As society has become more industrialized and urbanized and agriculture increasingly mechanized, the potential for such activities appears to be declining. It is postulated that such contact with the natural world plays an essential but unappreciated role in human development. Infants who are deprived of touch fail to thrive or develop normally and the healing benefit of touch therapy in adult patients is well recognized. Nurturing and caring seem to induce or be associated with significant psychological and physiological responses that have beneficial health repercussions.
Conversely, social isolation, bereavement an inability to care for others and lack of zest for work and daily activities are associated with increased susceptibility to illness, depression, and loneliness. Caring for and looking after other living things, regardless of whether they are people, pets or plants seems to provide a powerful buffer against such problems by somehow promoting the healing ways of nature (vis medicatrix naturae).