The evolutionary reasons humans love pets – and nine benefits of having one

We’ve all read stories about owners’ love for their pets, but you might be taken aback to hear how some people are willing to spend thousands of pounds on vet care for small animals like guinea-pigs and hamsters. A Guardian journalist recently reported spending £2,000 on vet bills for her guinea-pig, Ruby.

It really doesn’t matter what species an animal is if they meet a strong biological need. There may be deep-rooted biological reasons why we enjoy caring for pets. In fact, there are several evolutionary theories about why humans keep pets.

The connection between an owner and their pet is typically a close emotional one, and every bond is unique. When emotions are involved, relationships cannot be viewed in terms of their material worth. We should perhaps stop thinking about them in purely cold rational terms, as the human desire to care for another being is a powerful one.

Evolutionary theories that seek to explain this bond range from the biophilia hypothesis (humans have an intrinsic attraction to the natural world) to an inherent attraction or caring response to child-like characteristics such as a high forehead, large eyes and a shortened nose.

Evolutionary biologist Stephen Jay Gould argued that the evolution of the appearance of Mickey Mouse follows exactly this trend. Animators made him increasingly expressive over time, giving him a larger head, higher forehead, and shorter nose and limbs to make him “cuter”. These features are common in many popular cartoon characters.

Care-soliciting behaviour may strengthen this emotional bond. For example, guinea-pigs are known to “wheek” loudly in response to the sound of an opening fridge.

A stronger bond may form between owners and species or individual pets who require intense or special care, and show greater dependence on their human carer. But this doesn’t mean the more care a pet needs, the closer the bond its owner will feel for it. The emotional cost of problem behaviour, such as not being able to relax because a dog may spring at new people, can marr the relationship.

A relationship booster that transcends species

The cognitive ability of the species is largely irrelevant, so long as the owner can identify with their pets’ needs. The way we frame our relationship with a species is more important. For example, a mouse can be viewed as wildlife, a pet or a pest depending on the context, and we will treat it differently accordingly.

Caring for a pet is a relationship booster that seems to transcend species. My team’s recent work tried to unpick what it is about being a pet owner that is good for our psychological wellbeing.

Exactly how pet-related activities benefit us remains unknown – different processes might be happening in different people and several mechanisms might be operating at once, which can strengthen the bond. But our work has identified some recurring themes. If you are a pet owner, you might recognise many if not all of these.

Nine benefits of having a pet

1. Biophilia boost: interacting with and immersing ourselves within the natural world can be intrinsically beneficial to us, given our evolutionary history.

2. Caring and attachment: tending for another creature is a rewarding activity. It makes us feel good and develop a stronger sense of purpose.

3. Social support: having a pet nearby can reduce loneliness. Often, we may interpret pet behaviour in a way that provides us with emotional support.

4. Social catalysts: pets can be a social lubricant in many contexts. This might not only improve our personal networks, but also (indirectly) increase our sense of social support from others.

5. Emotional contagion: many of our pets look happy and carefree much of the time, and that can be infectious. A pet can help us surround ourselves with a more upbeat social circle.

6. Routines: caring for pets can put structure into our days and thus help reduce stress.

7. Exercise: many pets encourage us to exercise more, and this has neurophysiological as well as physical benefits.

8. Learning: finding out more about something, including animal behaviour, can be highly rewarding, especially when you achieve a degree of competence.

9. Physical affection: touch can have powerful effects on us, so petting may be psychologically very good for us.

There are also potential downsides to the processes that bring us closer to our pets. For example, you may experience social exclusion if your pet’s behaviour does not conform to social norms, such as being aggressive or pooping in the neighbour’s garden.

But pets, regardless of their species, can be important not only to how we feel but our sense of purpose and broader satisfaction with life. So, we should not be surprised when an owner appreciates that financial cost is of little importance when it comes to securing these goals.