American Scientist

CALLS BEYOND OUR HEARING: Unlocking the Secrets of Animal Voices. Holly Menino. 260 pp. St. Martin’s Press, 2012. $25.99.

Sixty years ago, ethologist Konrad Lorenz published a popular book on animal behavior titled, in the English translation by Marjorie Kerr Wilson, King Solomon’s Ring. The title derived from a fable of King Solomon, who was said to possess a magic ring that allowed him to converse with animals. Lorenz claimed that he could do the same without the need of magical assistance. His book charmingly described various aspects of animal behavior, with an emphasis on communication, in a way that was perfectly accessible to the lay reader while being scientifically authoritative for its day. Calls Beyond Our Hearing: Unlocking the Secrets of Animal Voices, by Holly Menino, in some respects follows in the path of King Solomon’s Ring. As the title implies, Menino emphasizes animal communication, but as in the earlier book she wanders into other areas of animal behavior as well. And like Lorenz, Menino writes gracefully and engagingly of the behaviors she observes. Where Menino and Lorenz part company is in their scientific expertise. One does not need to be a Nobel laureate, or even an ordinary scientist, to write a useful book of popular science. It helps, however, to have a better grasp of the relevant science than what is revealed here.

Calls Beyond Our Hearing is structured around visits to a series of ongoing research projects on the vocal behavior of vertebrate animals. Menino starts with studies of male advertisement calls in túngara frogs and proceeds to research on the roaring of red deer stags, duetting in elfin woods warblers, alarm and contact calls of meerkats, auditory processing in whales and self-recognition in elephants. Some of these examples are well chosen to address what emerge as her two main interests: the function of vocalizations in nonhuman animals, and evolutionary precursors of human language and music. Mike Ryan’s work on túngara frogs, which demonstrates female attraction to males’ calls, is as relevant to the functional question as any current research. Marta Manser’s studies, showing that different meerkat alarm calls refer to specific types of predators, are similarly germane to the question of language precursors. The inclusion of whales is more difficult to understand. Whales are notoriously difficult to study. Given that, under natural conditions, we can seldom determine which whale has vocalized or what the response of listening whales has been, progress on the question of function has understandably been slow for this group. Studies of cultural traditions in the vocalizations of killer and humpback whales are arguably relevant to the language precursor question, but we are not told about these; instead Menino concentrates on what can be seen of whale behavior from the deck of a boat on the St. Lawrence estuary. She does introduce a project on auditory processing in dolphins, in which researchers are using electroencephalograph recordings to measure the response of their subjects to sequences of sounds. Although she outlines the methods used in this work, few results are given. The other chapters are more relevant to the book’s main themes, but even in these Menino often emphasizes whatever research is currently being done, at the expense of past work that more directly addresses her central questions.

Another problem is that Menino sometimes gets theoretical concepts a bit muddled. Take her treatment of the handicap principle, which she introduces as an explanation for signal reliability in the chapter on the roars of red deer stags. These roars reliably communicate a stag’s body size, in the sense that size is consistently correlated with observable features of the roar, such as minimum formant frequency. A formant is a frequency band emphasized by the resonances of the vocal tract; because longer vocal tracts allow resonance by longer wavelengths, minimum formant frequency decreases with increasing vocal tract length. Larger individuals are inevitably able to accommodate longer vocal tracts, producing an association of body size with minimum formant frequency (and by extension with formant spacing). A signal whose reliability is mandated by inescapable relationships between physical properties of the signaler’s production mechanisms and attributes of the signal is termed an “index signal.” The handicap principle explains signal reliability as due to signal costs: A costly signal can be reliable about signaler quality because only a high-quality signaler can afford to pay the costs of producing it. An example here is that call rate can be a reliable signal of energy balance if calling is energetically costly, because the fitness costs of expending energy are lower for signalers with good energy reserves than for those with poor reserves. The handicap principle is a legitimate explanation for certain instances of signal reliability, but it does not explain the red deer roar/body size relationship. Invoking handicaps in that context, and neglecting the index signal argument, must confuse the reader on the relevant science. Other examples of muddling include Menino’s conflation of the cocktail-party effect (selective attention to important vocal stimuli) with the Lombard response (an increase in vocal effort when vocalizing under noise); dubious generalizations such as that each animal’s voice is “perfectly adapted” to its circumstances and that birds have “dramatically” more complex social lives than red deer; and dismayingly vague characterizations of concepts such as Hamilton’s Rule and game theory.

I was also dismayed by the discomfort Menino expresses with scientific values such as objectivity and reduction. Objectivity becomes an issue in part because of the use by scientists of terms such as “signal” and “signaling” in place of more emotive alternatives such as “word” and “language.” Reduction becomes an issue because of the predilection of behavioral ecologists to explain the evolution of behavior as due to natural selection for traits that increase an actor’s individual fitness. Menino expresses her various discomforts as follows: “Having always thought of myself as an animal lover and encountering these ideas about signaling and self-interest for the first time, I found that my first reaction was to be repelled. I was turned off by what I thought was a bloodless reduction of animal life to the interplay of numbers.” She eventually reconciles herself to the terminology preferred by researchers, saying later in the book that “Maybe calling a red deer stag a signaler and a red deer hind a receiver seems contrived, but these notions have carried us to our current understanding of the ways animals use their voices.” If she reconciles herself to the “bloodless reduction of animal life to the interplay of numbers,” she does not tell us so.

The value of Calls Beyond Our Hearing lies in its storytelling. Menino’s descriptions of animal behavior are interesting and well written, and the anecdotes about the various research groups she visits contain detail we would never learn from their scientific papers. We get glimpses of the personalities of individual researchers as well as enjoyable accounts of the day-to-day problems of actually doing the research, such as the difficulty of trailing along after meerkats for hours and hours without disturbing them, or of inducing elephants to respond to a mirror without destroying it first. Nevertheless, it is unfortunate that Calls Beyond Our Hearing does not quite reach the bar Lorenz set long ago, with full measures of both charm and precision.

William A. Searcy is Robert E. Maytag Professor of Ornithology at the University of Miami in Coral Gables, Florida. His research examines aggressive and courtship signaling in song sparrows and swamp sparrows. He is the author with Stephen Nowicki of The Evolution of Animal Communication: Reliability and Deception in Signaling Systems (Princeton University Press, 2005).