“Humans feel affection for animals with juvenile features,” noted Konrad Lorenz. “Large eyes, bulging craniums, retreating chins. Small-eyed, long-snouted animals do not elicit the same response.”

This induces people to care for small, cuddly animals. “And this has led some experts to argue that the entire phenomenon of pet-keeping is nothing more nor less than an elaborate case of social parasitism,” writes zoologist James Serpell. “Needless to say, this idea has done little to promote a positive view of pets or their owners. Rather, it creates the impression that pet-owners are the victims of some kind of bizarre affliction, and that dogs, cats and budgerigars are little different from body lice, fleas or tapeworms or, indeed, any other sort of parasitic organism.”

(From James Serpell, In the Company of Animals, 1986.)