“Two chimps had been shut out of their shelter by mistake during a cold rain storm. They were standing dejeted, water streaming down their shivering bodies, when Professor Köhler chanced to pass.” Upon opening the door for the two chimps, Dr. James Leuba recounts, “instead of scampering in without more ado, as many a child would have done, each of them delayed entering the warm shelter long enough to throw its arms around his benefactor in a frenzy of satisfaction.”
“Chimpanzees,” primatologist Frans de Waal points out, “do not normally hug their caretakers for no reason.” It’s a compelling image, isn’t it? The idea that at least some animals might be capable of feeling and communicating gratitude? If we wish to make an argument that some animals possess at least some sort of proto-gratitude, or the cognitive building blocks required for them to feel and express gratitude, we first have to decide what gratitude really means.