For those who put sapiens on pedestal; be humble, curious, and embrace awe and wonder.
Despite their cultural popularity, wolf howls haven’t been the subject of focussed research until recently. Now, following the lead of marine biologists and ornithologists, and with improved sound recording equipment and analysis programs, researchers can study them in depth. The first step in understanding what animals are saying to one another is to figure out what aspects of the voice are functional and what parts are formed by the structure of the throat and mouth, or what is the piano and what is the tune. Studies since the 1960s have shown that the howls that have haunted our dreams for centuries can tell us a lot about the particular wolf vocalising. Like humans, each wolf has its own voice. Each pack also shares howl similarities, making different families sound distinct from each other (wolves respond more favourably to familiar howls). This much we knew. What we didn’t know was whether the differences seen between packs were true of subspecies or of species, and if an Indian wolf howl would be distinct from a Canadian one.
More questions follow. If howls from different subspecies are different, do the howls convey the same message? Is there a shared culture of howl-meanings, where an aggressive howl from a European wolf means the same thing as an aggressive howl of a Himalayan? And can a coyote differentiate between a red wolf howling with aggressive intent and one advertising the desire to mate? Even without grammar or syntax, howls can convey intent, and if the shape of the howl changes enough while the intent remains constant, the foundations of distinctive culture can begin to appear.
To explore this, Kershenbaum brought together a group of researchers to share data and ideas. We compared howls across 13 different subspecies and species of coyotes, dogs, wolves and jackals (collectively known as canids). The howls came from my own recordings on chilly evenings in Poland and Russia; from UK zoos and conservation sites (where I howled at the bemused wolves and listened in awe as they responded); from our co-authors in the US, Spain and India; from historic recordings taken across continents and time; from the public, in the form of hundreds of YouTube videos of howling pets. Our canine voice collection represented was one of the most comprehensive ever.
We then stretched all the howls to the same length, using a process called dynamic time warping, to compare the changes in the tune without including the tempo it was played at. We found that each species had its own favourite howl shape, a preferred set of changes to their howls to raise and drop the pitch, but that they also used howl shapes preferred by other species, and varied the shapes as they pleased. The species were like music bands with preferred styles of playing, whether riff-filled like jazz or the pure tones of classical, but were flexible in what they actually played at any given time. So while they had a favourite style, the tune itself varied.
Like musicians, the wolves were influenced by their forebears in the genre, and species shared traits with other canids that were closer to them geographically and genetically. An Eastern grey wolf, recorded in the US, sounded more like a North Carolinian red wolf than a European wolf, and an African jackal sounded quite different again. Small and delicate compared with their cousins the European wolves, golden jackals have high, rising howls, running up and down the scales in bravura performances of control and speed, but with less variation in overall shape, whereas the European wolves used a slower style of deep and steady long notes ending in falls that seem to drift away into the night. New Guinea singing dogs earned their names with a large vocal repertoire and a wide selection of howl shapes. While sometimes the different species achieved crossovers to other shapes, most had a style that dominated their repertoires.
If these differences across species sound familiar, they should. We’ve known for thousands of years that birdsong is distinct to each species, and sometimes even populations, with a nuthatch’s wha-wha-wha very different to a robin’s whistling call. We’ve seen that birds have adaptable repertoires, literally changing their tunes as new sounds become popular and spread through populations. Humpback whales sing new songs when they hear them, collecting new patterns of song throughout their lives and passing them on to others in their population. Our canid study showed that they had different howls for their species, but we have yet to answer whether they can change their howls with time or exposure to different howl patterns. Now that we’ve seen there are differences, the next question to answer is whether they are innate or learned, and how far a wolf can change its howl.
No comments:
Post a Comment