by Dov Michaeli
A few days ago my granddaughter called me with one of her never ending, always challenging, questions. “Why, she asked, are cicadas singing?” This one was easy, I thought. Male cicadas sing to attract females so they can mate. As do crickets. And birds, I added as an afterthought. But now I was treading on shaking ground.
Birds do it…
The common wisdom is still that male attract their mates with a song and dance, literally. And after the deed is done? Hasta mañana baby, see you next spring. Now comes a study from France to inject a bit more romance into the relationship. As reported by Brandon Keim in Wired Science (Aug. 10, 2010) on research conducted by Clementine Vignal, a sensory ecologist at France’s Université Jean Monnet. She took advantage of the lax laws governing privacy and unauthorized listening in France and placed tiny microphones in the nests of zebra finches, a species common in Europe. And what she heard was truly intriguing, and in a moment you’ll find out why.
[singlepic id=17 w=320 h=240 float=left]Zebra finches are monogamous, and 4% of such birds sing duets during the mating season. But zebra finches don’t even duet during courtship, and only males sing songs. But the investigators soon heard the birds exchanging synchronized clicks and trills performed when one left or returned to the nest, or was nearby while the partner remained. As Vignal stated, “… scientists may have been blinded by an assumption that duets were purely a mechanism for advertising virility and reproductive health to would-be mates.” But this study puts the birds in a new and surprising light. As Brandon Keim of Wired Science puts it “were the singers human, researchers might also explain the duets in terms of affection. Since they’re birds, the researchers describe the songs in terms of maintaining pair bonds, predator avoidance and conferred reproductive advantages”. Vignal, the lead author of the paper, references studies showing elevated levels of stress hormones in separated pairs, and concludes that “ they have emotions. They’re certainly different from the ones we accept, but they do have them; we can imagine that this duet expresses some kind of emotion.”
My guess is that not only zebra finches have emotions. Neurobiology teaches us that feelings of stress, rage, fear and pleasure are located in the amygdala –an agglomeration of neurons in the midbrain, which is an ancient part of the brain. So it would not be a great stretch to assume that even lowly vertebrates such as lizards (forerunners of the birds, in evolutionary terms) have some sort of emotions.
How can we study animal emotions?
In a review published in the Proceedings of the Royal Society B researchers tried to tackle this difficult problem. After all, how do you judge an animal’s emotional state? We can probably recognize our dog’s mood, but what about a bird, or a croc? The researchers devised a model that correlates emotional state to decision making. How would an animal react to, say, a rustle in the forest. If the animal is assuming a defensive “safety first” stance, it is probably feeling pessimistic. If however the animal is feeling optimistic, it would interpret the same rustle as a sign of prey. Sounds a bit squirrely; but this model on extensive data gathered of rodents, sheep and pigs and yes, humans placed in different environment.
Is the time far when we veterinarians and psychiatrists will be trained in crocodile psychiatric conditions? After all, we already have dog psychiatrists; and from what I hear, talk therapy is as effective and as expensive for dogs as for humans…