In this episode we discuss Chapters 4 & 5 of Darwin's The Expression of the Emotions of Man and Animals, 3rd Definitive edition. Chapter 4 documented how animals use specific sounds and body postures to communicate their current emotional state. We explored how familiar we are to the sounds of domestic dogs and cats and the information they encode in their vocalizations. James was intrigued with the idea that early human language may have been more musical than expected. Mark spoke about the work of Dr. Diana Deutsch and her discovery we can extract music from spoken words. Here is the link to the wonderful Radiolab story that covers this phenomenon. At the end of our discussion Mark read a quote from Darwin concerning the behavior of fighting cocks to erect their neck feathers - something "Every one must have seen two cocks...preparing to fight with erected neck-hackles. Photo from https://www.behance.net/gallery/4810345/Cockfighting-in-ThailandWe discussed if it was legitimate for Darwin to identify the behaviors he was describing in dogs, cats, horses, monkeys and apes as being fear, affection, joy, anger and astonishment. Mark brought up the idea of Morgan's Canon, which argued against using complex anthropomorphic interpretations of a behavior when a simpler, basal behavioral state can explain the behavior. For example, Tony, Morgan's terrier opened the gate through trial and error and not because of some insight about the gate mechanism.Tony opening the gate so he can go out and sniff some buttsSarah noted that Darwin seemed to ignore the evolutionary history of dogs and cats to help explain their behaviors. Domestic dogs evolved from wolves, a social pack animal, which can explain the complex set of stereotypical dominant and submissive behaviors they exhibit whereas domestic cats evolved from wild cats that were solitary. James declared that Jackals, a group of canines that Darwin incorrectly proposed to be the progenitor of some smaller breeds of dogs, were solitary. Turns out, Jackals are typically found as monogamous pairs, but the social group can increase with young. So they are not solitary like big cats, but they are not as social as wolves. The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh.