Our family dog may be the nicest "person" on the planet. Okay. He's not perfect. He does bark at the postman every day. And you have to make sure the trash bins are covered or he'll grab and shred every used tissue, then scatter the pieces around the house.
But he's a love machine. He wants nothing more than to be in the room with the humans in his family or on a lap, licking a hand. And this feels very good to us. We hope he likes it, too.
Don't worry, cat lovers. We love cats, too. And theoretically we love pigs. We realize not everyone feels this way about pets, or any animal for that matter.
But more than half of U.S. households have one or more pets living there. In some estimates, as many as three-quarters of homes with children have one or more pets.
People are very attached to the animals living with them: In an Australian survey published in 2006, more than 90% of people said they felt very close to the family pet.
I can't promise that you'll feel better if you bring a pet home, but owning a pet is associated with better mood and quality of life.
Most of the research on the bond between humans and animals revolves around dogs, so that is the focus here. The principles may apply to other pets.
Our hunter-gatherer ancestors certainly spent a lot of time interacting with animals. They tamed many and even invested some with special god-like status.
The relationship between humans and dogs goes back at least 10,000 years and probably longer. Experts say that dogs began to evolve from wolves about 40,000 years ago. According to biologists, wolves and dogs are still genetically almost identical. The main difference is in their relationships to humans.
Dogs — and their wolf ancestors and cousins — are social animals who, like humans, have a predisposition for pack or group behavior. As the writer, Mark Derr, described in Dog's Best Friend: Annals of the Dog-Human Relationship, hunter-gatherer humans came into regular contact with wolf packs. They may have even learned a thing or two from watching how wolves worked together to capture dinner.
Human and wolf groups are also similar in social structure. Each cares for and educates its young. Survival depends on communication and cooperation.
Humans also can empathize with these animals. We recognize their moods and intentions from how they hold their heads, position their bodies or move their tails.
There's been a generation of research on how owning a pet affects human health and happiness. For example:
Here are some of the ways researchers think pets make a difference:
Animals have emotional needs, too. You have to be ready to help and nurture them. Pets must be fed and groomed. Even when it's 10 degrees outside with 2 feet of snow on the ground, you must give them the opportunity to "do their thing." You have to take them to the vet for routine care, think about their reproductive needs, and make sure they are well behaved, especially around people who fear them.
If you don't particularly like animals or respond to them, they won't make you happy. If anyone in your home doesn't like animals or is allergic to them, don't invite one into your home. And although it is fairly rare to catch an illness from your pet, it can happen, so consult your doctor if you have an illness that makes you more vulnerable to infection.
One drawback is unavoidable: If you become attached to your pet, you will mourn its death.
Our dog is a love machine. He makes us happy, and his loving nature more than makes up for any barking or paper shredding. With any luck, your pet will make you happy in similar ways.
Michael Craig Miller, M.D. is editor-in-chief of the Harvard Mental Health Letter and an assistant professor of psychiatry at Harvard Medical School. Dr. Miller has an active clinical practice and has been on staff at Beth Israel Deaconess Medical Center for more than 25 years.