DOI link for Communication
DOI link for Communication
About the first question visitors ask, when they walk into our lab and observe a recording of orca acoustics in progress, then notice the pile of tapes, growing daily, that represents decades of such effort, is: ‘What are they saying?’. Our answer amounts to ‘don’t have a clue’, though this is usually followed by references to what we do know, or think we understand, i.e. that orcas use echolocation when they are hunting, that we can tell when they are excited and when they are resting, and when they are engaged in the ordinary social exchanges that keep them in touch with one another over considerable distances in the ocean. But beyond that, our understanding lies in a murky grey mist, as if we’re adrift in fog on a flat ocean, barely seeing beyond our bow, and without even the hint of a wake to tell us in which direction we should go.
Without question, orcas communicate, as do all other species of whales, certainly with their own kind and quite possibly with others, but the precise content of their communications remains elusive. Thanks to John Ford’s work on orca acoustics (Ford, 1989, 1991) we’ve known since the 1970s that orcas use dialects that are unique to their family groups, and that these dialects are passed down through the maternal lines. Orca dialects are no doubt very useful as tools that promote group cohesion and cultural identity (see Figures 13.1 and 13.2). It is also clear that differences in dialects between groups within a community pose no barriers to social communication. Groups having no commonality in their dialects are quite comfortable with one another when they meet, going about their mutual business in agreeable harmony, enunciating whatever it is they are talking about calmly or with great excitement, even in complete silence, as their moods or circumstances take them. The upshot is a mystery, perhaps akin to that Egyptologists faced when they first encountered hieroglyphics, so what we may need is something like a Rosetta Stone for orca – possible one day, perhaps, but at this stage very much out of discernible reach. In the meantime, we are left with
speculation; some observers believing that orcas are engaged only in repetitive ‘I’m here’ kind of statements that enable everyone in a group to know where the others are within an acoustic space; others believing it possible or likely that precise details of what individuals are encountering are being encoded and transmitted, and
Figure 13.1 The closest communication among orcas occurs between mothers and their offspring, here A42 (Holly) with her 2008 baby (A88)
Figure 13.2 Orca A42 (Holly) with her youngest daughter (A88) and eldest son (A66)
even that exchanges can include complex thought content. The common element in these views is that communication is shared; the difference is in the level of sophistication ascribed to the whales.
Sperm whales, possessed of our planet’s largest brains ever, display social and acoustic traits that are quite similar, though not identical to those of orcas; they also display traits that are similar to those of the largest-brained terrestrial mammals, elephants. Sperm whale populations are organized as societies that occupy loosely defined ocean realms; roles within the society are structured in space and time to provide the essential means of life and living to all members. Some basic facts were known from observations of old-time whalers and data from the modern whaling industry, but it wasn’t until the non-intrusive deep ocean studies, patiently conducted from sailboats by Jonathon Gordon, Hal Whitehead and Lindy Weilgart, beginning in the 1980s, that details began to emerge (Whitehead and Gordon, 1986; Whitehead and Weilgart, 1991).
It turns out that sperm whales, like orcas, use sounds that vary between groups and amount to group-specific dialects, and they display behaviour consistent with the notion that they too, possess culture. Communication in sperm whales is accomplished using ‘codas’, which consist of a series of complex clicks, with nonrandom spacing between clicks and variability in the number of clicks; it has been speculated that the sonic structure of codas may be amenable to mathematical analysis. What are we to make of this, and what role does communication play in the functioning of sperm whale (and other cetacean) societies? It is easy to believe that big-brained, sentient, acoustic, social beings are capable of profundities that are expressed in their communications, but very difficult to prove. Inescapably, therefore, one’s view of communication in and among whales comes down to one’s core set of beliefs about them.
Whatever may be sorted out ultimately, sounds made by whales have intrigued people since ancient times. Aristotle, 2300 years ago, used the voice of dolphins to help separate them from fish; in past centuries, whalers in wooden ships drifted off to sleep to the songs of whales; and recent decades have seen remarkable progress in our observational skills and knowledge base, if not exactly in our understanding of whale communication. The quest began in earnest in the 1960s, initially with John Lilly’s studies (Lilly, 1961, 1967) of dolphin brains and vocal mechanisms, and his conclusions about their potential role in sophisticated communication; his work, which was not universally embraced by the scientific community (more rejected than accepted), was followed by the collaboration between Roger and Katy Payne and Scott McVay (Payne and McVay, 1971), which led to the discovery that humpback whales create songs that bear remarkable resemblances to works of music created by humans; this knowledge caused such a stir, that the immediate product, an LP disk titled Songs of Humpback Whales (1970, CRM Records) became a pop culture icon of the 1970s; as a result, humpback songs were included in the Golden Record1 carried aboard the Voyager spacecrafts launched in 1977, with the purpose of taking evidence of the diversity and complexity of life on Earth to the far reaches
of our solar system and beyond, on the off chance that it might be discovered by beings in some distant place and time, who would be able to decipher the content and know with certainty that our tiny jewel of a planet had nurtured intelligence; the languages of human cultures were there, and so were the voices of whales.
In the five decades that have elapsed since the 1960s, considerable effort has been devoted to further describing the vocal capabilities of dolphins, including their sound production mechanisms; we are gaining a fascinating picture of the precise control over phonation that is exercised by dolphins and other odontocetes via controlled movement of air inside the head; pairs of tiny ‘monkey lips’ located under the blowhole give dolphins at least two simultaneous and independent sound production sources (Cranford, 2000) – an extraordinary capability that carries implications for potential communication complexity. What functional use is made of this capability is presently unknown, but little pieces of the puzzle are emerging.
Studies of ‘signature whistles’ in dolphins suggest that these sounds are used as individual identifiers corresponding to ‘voices’ in large groups, where knowing the location of close companions or relatives is important to group function and cohesion. Peter Tyack’s method for determining the individual origin of vocalizations in groups (Tyack, 1985), which he developed with captives, and with colleagues applied to wild dolphins, has produced intriguing results, but the technique has a drawback in requiring physical attachment of monitoring gear; it’s use is therefore limited to controlled situations, i.e. captivity or very accessible wild groups. Signature whistles are retained by individuals for at least ten years, lending credence to the notion that communication between individuals in groups of dolphins is structured and that it endures over time. Moreover, complex variations occur within basic signature whistles, making it likely that they contain far more than identifier information (Sayigh et al, 2007). To dolphins, then, the cacophony we hear via our hydrophones probably makes perfect sense – everyone knows who is speaking, where they are and (presumably) what is being said.
The songs of humpbacks have been studied in numerous populations and locations since their discovery in the 1960s (Payne and McVay, 1971). Researchers generally agree that the songs are made exclusively by males (Darling et al, 2006) but their precise purpose remains uncertain, even controversial. Given that the songs are mostly sung during the winter season, when humpbacks gather in warm shallow waters to have babies and find mates, it seems arguable and logical that the songs are a form of male display that serve to attract females; but if this is the case, the precise meaning, and the mechanism, remain elusive. Perhaps the annual humpback song fest, in which a new version of last year’s song spreads rapidly across whole ocean basins, is a form of grand harmony, in which voices, though separated by thousands of kilometres, rise in joyous unison, with some being more perfectly in tune than others; but perhaps the answer is more mundane, even that the songs are a precursor to the blood sports some insist male humpbacks engage in as they compete for female access and attention. The ‘Gentle Giant’ is nowhere to be found in this scenario; yet the evidence is overwhelming that humpbacks
routinely display extraordinary restraint in the face of mortal danger, as when they are entangled in fishing gear and being assisted by humans; the aftermath of a successful release is often so poignant as to be tear-provoking, with the whale acknowledging the rescuers with gentle touches and eye-to-eye contact, that, as communication, leave no shadow of doubt as to intent and meaning. It seems ironic that communication between whales and people may be easier to understand than communication between whales themselves. Perhaps this is because we are active participants; also, the questions asked are simpler. If we were to confine ourselves to describing the role that touch plays in interactions between members of cetacean groups – certainly vital – we might find the road to understanding easier. But that is not where we’re at – we want to know what whales are saying.