Indri lemurs have a beat that is comparable to our own, according to research into one of the few primate groups known to “sing.” The discovery of musicality in these lemurs is a significant step forward in the study of the musical tree of life, allowing scientists better understand how rhythm initially arose and spread through shared ancestors. While humans and birds have demonstrated musical ability, this is the first indication of categorical rhythm in a non-human mammal. A song with categorical rhythm is one in which the notes or beats have constant lengths. It is essentially, what distinguishes music from other noises, and it is why you can recognize a song even if it is played at double the normal tempo.
The study, which was published in the journal Current Biology, recorded the songs of 20 indri lemur groups over the period of 12 years to see if they had this kind of rhythm. In total, they had 39 animals in their sample, who would sing duets and choruses together. According to a previous study, juvenile indri lemurs would sing out of tune to draw their parents’ attention. The recordings revealed that the lemurs indeed have a rhythmic pattern, with various tendencies emerging throughout their song. There were sex disparities in singing style, as males and females sang at different tempos while sticking to the same rhythm. Songs demonstrated “ritardando,” a technique in which a song gradually slows down, and even suited the rhythmic category of perhaps one of humanity’s most renowned musical beginnings.
“Rhythm is highly important in human music, and intervals between the beginning of one note and the beginning of the next note usually have a straightforward relationship,” first author Chiara de Gregorio told IFLScience. “For example, two following periods could have the same length, or the second could be twice as long as the first. “These two situations correlate to two rhythmic categories, and we can hear them in the intro of Queen’s renowned song “We Will Rock You.” What’s more, guess what, those are the same two rhythmic types we found in the songs of the indris. This is the first time that a characteristic of human music has been found in another species.”
Their musical abilities raise issues about how this gift helps them fit in better with their surroundings, and where a common ancestor (if one exists) fits in the evolutionary chronology to explain why different tribes have evolved the skill independently. According to the study, humans and indris shared a common ancestor 77.5 million years ago, implying that music may have deep roots among mammals. “Music and rhythm are two extremely crucial parts of our daily lives,” de Gregorio explained. “However, the reason why we appreciate music and dancing so much is hotly discussed. The discovery of musical universals in indris could indicate that human music isn’t actually innovative, but that its basic musical features are more deeply anchored in the Primate lineage than previously considered.”