Three photos of passages from Bernd Heinrich's book The Nesting Season.
In this movie, the filmmaker Luc Jacquet faced down the demon, of not the taboo, of anthropomorphizing an animal. And I, as a biologist, was asked by the New York Times to write an editorial about March of the Penguins (August 26, 2005). Naturally, in my essay, I had to comment on Mr. Freeman's use of the word "love" in the context of the penguin's behavior. I wrote:
The unspoken rule is that this four letter word is to be applied only to one creature on earth, Homo sapiens. But why? A look at the larger picture shows this presumption of exclusivity is utterly unproved. In a broad physiological sense, we are practically identical not only with other mammals but also with birds—muscle for muscle, eye for eye, nerve for nerve, lung for lung, brain for brain, hormone for hormone—except for difference of detail of particular design specifications. Functionally, I suspect love is an often temporary chemical imbalance (relative to when not "in love") of the brain induced by sensory stimuli that causes us to maintain focus on something that carries an adaptive agenda. Love is an adaptive feeling or emotion—like hate, jealousy, hunger, thirst—necessary where rationality alone would not suffice to carry the day. Could rationality alone induce a penguin to trek 70 miles over the ice in order to mate and then balance an egg on his toes while fasting for four months in total darkness and enduring temperatures of minus 80 degrees Fahrenheit and gusts of wind of up to 100 miles an hour? And bear in mind that this 5-year-old (minimum age at first breeding) penguin has just returned to the place of its birth from the open sea, and this has never seen an egg in its life, and could not possibly have any idea what it is or why it must be kept warm. Any rational penguin would eventually say, "To heck with this thing, I'm going back for a swim and eat my fill of fish."
My implication was that love is not a mystical arrow shot from heaven. It is something as real and adaptive as a bird's beak or our hands. We have less trouble acknowledging behaviors that we attribute to "stress" across species. There is scant objection to identifying behaviors associated with elevated levels of corticosterone hormone in humans, birds, and mammals. So if penguins experience the behavioral state we label as "love," then we would predict similar hormonal and neurological changes that are diagnostic in us. On the other hand, we could not even begin to speculate what insects might feel, if they feel at all, because they have very different hormones and few behaviors that we can "read" as expressions of our emotions.