When companion animals or therapy animals – or pets - walk into a room, people often brighten up. Most of us have encountered someone with a service dog, seen a therapy dog at work, or experienced the healing power that can come from having a pet. For many people, animals are central to their overall health.

This clinical tool focuses on the health benefits of pet ownership and, more specifically, animal-assisted therapy (AAT). How might animals contribute to a person’s health?   

Animals and Health: A Background

According to the National Pet Owners Survey, 68% of households owned a pet as of 2017. This is up from 56% in 1988.¹ 40% of Americans own a dog and 29% own a cat.² There are 90 million dogs, 94 million cats, 139 million freshwater fish, and 20 million birds that are pets in the US.

The biophilia hypothesis holds that human beings are genetically predisposed to have an affinity with other organisms. The hygiene hypothesis posits that being around pets leads to exposures to allergens that strengthen the immune system, and therefore being around animals, especially as a child, can give rise to certain health benefits.³

Humans have been connected with animals since before recorded history, as is evidenced by cave paintings from around the world. The first documented use of animals therapeutically was in ninth-century Belgium, when people with disabilities were asked to care for farm animals. Animals were used in the 1700s at the York Retreat, a progressive “lunatic asylum” for its times. In the 1800s, Florence Nightingale recommended animals as companions for the infirm.³

Animals can contribute to health in the following contexts:⁴

• As pets
• As resident animals—living in a facility and being cared for by its staff, residents, or volunteers)
• As service animals—examples include dogs that assist people with visual impairments
• As pets that visit people with no specific therapeutic goal on the agenda—known as animal-assisted activities (AAAs)
• As the focus of animal-assisted therapy—the use of an animal in a therapeutic setting to bring about a specific set of goals (AAT can be provided in a variety of settings, to both groups or individuals. It is delivered under the supervision of a trained human service provider.)