After Hurricane Katrina hit the Gulf Coast of America in 2005, researchers questioned individuals who were able to leave the city but chose to stay. Around 18 percent said they stayed because they did not want to leave family members but nearly 50 percent of them would not leave their dogs and cats. 1,400 people died that day; some of them surely died because they loved their pets too much.
Evolutionary psychologists argue that caring is a technique present from birth, designed to keep us alive by helping relatives or others who will someday help us. Why, then, should we invest time, money and love in animals, who are unlikely to ever return the favour?
I believe our love for pets comes from three features of human nature: natural instincts, culture and empathy. The human brain makes us feel warm and happy when we see baby cheeks and big eyes. This developed to persuade us to take care of our own young. But it makes kittens and puppies seem attractive too. It also explains why we feel strongly about an animal such as a baby seal, yet care so little about one like the much rarer - but rather ugly - Chinese salamander.
But if this theory is true, we would expect that pet-keeping would, like music, be found in all human societies. This is not the case. In the Kenyan village where anthropologist Nyaga Mwaniki was born, people use dogs to guard against strangers and chase away wild animals. The dogs, however, are never touched or allowed to sleep in a human's bed. Indeed, Nyaga's native language does not even contain a word for 'pet'.