Written by Karen Bakker


Review by Gunnel Minett

It is said that David Attenborough has done more for the environment with his films than any government scheme. For many they have been an eye-opener to see that human beings are not the only social beings on our planet. This book takes us one step further by illustrating how animals, which scientists have previously claimed could neither; make sounds, hear or communicate, are interacting with each other. They may be using sounds, and possibly other ways of communicating, which we find difficult to explain unless we turn to quantum physics. 

Alongside the technical development of microphones and listening equipment, scientists have developed a whole new discipline; that of bioacoustics, or sounds made by living organisms, and ecoacoustics, or acoustic ecology or soundscape studies, i.e. studies of environmental sounds.

It has been something of a revelation to science to find that animals who, it was assumed could neither make nor register sounds, actually are doing both, often in very organised and specific ways. Using modern listening equipment scientists have discovered, for example; that a degraded ecosystem sounds different from a healthy one, that marine mammals employ different types of sound communication, that killer whales pods have different dialects, that whale babies babble and imitate sounds made by their family when they are a few months old, that some whales use sounds to navigate with echolocation, and that some whales sing in the infrasound range.

The author is keen to point out that these findings have often been confirmed by indigenous people, who are familiar with whales because of their hunting traditions: “The Inupiat know that whales have complex societies, communications, and even emotions. … whales listen, and that if a hunter is disrespectful or selfish, whales will avoid them. To hunt well, you need quiet and harmony in the boat; even the women sewing the sealskin boat must speak gently. … Hunting is both a prosaic, messy necessity and an act of ceremony.” (p42)

But it is not just the oceans that have a soundscape, the author goes on to describe the interactions of other animals which have only recently been understood thanks to new technology. When scientists recorded elephants at increased speeds they discovered that elephants communicate with infrasound, below the frequency that humans can hear. They were able to document intricate and sophisticated social networks, which extended well beyond the core family group, encompassing scores of elephants across several generations. 

It did not stop there. Scientists have also provided evidence that elephants can determine  ethnicity, gender and age from acoustic cues. These studies have been so successful that scientists now are using similar tools and Google Translate to create a dictionary in order to communication with elephants. This is not to say that they are trying to become Dr Doolittle who could talk to animals, but rather as a method to learn to communication with animals. This can give us a better understanding of how they live in social environments. This constitutes an innovative form of two-way communication with non-humans via AI.

Understanding the soundscape of other species has opened up completely new possibilities in many areas. Here are some more examples listed in the book:

[Scientists] “found evidence that turtles use sounds to coordinate their behaviours, like hauling out of the water to bask in the sun.  … leatherback hatchlings’ most sensitive hearing range… corresponds to the sound of waves on the beach… , which may hep them find their way to the waves immediately after being born.” (p.72-73)

“By listening to the entirety of noises in the soundscape of, say, a pond, we can discern sounds from multiple species and the landscape they inhabit. This sheds new light on ecosystem function and condition.” (p.75)

“Turtles have the physiology that makes them capable of both making and hearing sound, and it seems narrow-minded to assume that parental care is unique to mammals.” (p.79)

“Sea creatures, it turned out, were noisy beasts, and they could both hear and make sounds along a wide range of the sonic spectrum – often well beyond human hearing.” (p.84)

“The Palauan fishers not only recognised that fish larvae could navigate across the oceans; they actively cultivated this knowledge to their advantage.” (p.90)

…”despite spending weeks drifting in the open ocean, fish larvae can not only hear and respond to the sounds of the reef, they also swim toward healthy reef sounds…. The most recent research confirms that the success of coral reef restoration is detectable in the soundscape; recordings of the reviving reefs in Indonesia even include sounds entirely new to science – whoops, grunts, and growls that perplex researcher.”(p.94)

The notion of talking to your house plants in order to make them grow better is well known to many housewives. However, few of them would imagine that plants also can make sounds. But now science has started to study this methodically and developed new research fields – phytoacoustics (the study of plant bioacoustics) and phonotropism (plants responding to sound).

Sound is also central to South-American shamanic traditions. Their shamans undergo a period of isolation in the forest as a necessary part of their initiation rite. “Listening to the sounds of and songs of nonhumans is a form of sacred ecology.” (p76) 

The research in this field hawks back to our very earliest known science, as practised by ancient Greeks philosophers, such as Aristotle. He declared that although all beings have souls, only humans have rational souls. Animals possess varying degrees of knowledge and have merely ‘sensitive’ souls. And plants, at the bottom of the hierarchy, possess merely ‘vegetative’ or ‘nutritive’ souls. Researchers have now fine-tuned Aristotle’s understanding and demonstrated that plants possess memory, anticipate events, and can even communicate with other plants and  animals. Planets in fact possess a complete set of sensory mechanisms which underlie these behaviours; a ‘vegetal sensorium’

As a result, there are now computer programs that can detect the relative health of plants just by listening to them. Part of the basis for this development is the assumption that sound is a fundamental form of energy transmission. The conclusion is that organisms which can ‘hear’ better, also adapt and survive better in their environments. Scientists call this the auditory scene hypothesis. But, the author is keen to point out, research on plant sounds is not necessarily concerned with plant feelings. 

Another area of bio-sound research, concerns bats. Bats are capable of vocal learning, and use complex communication to guide social behaviour in a manner similar to humans. As in humans, baby bats learn by vocal imitation of adults. Bat songs, like whale songs, are also culturally transmitted and evolve over time.

The philosopher Thomas Nagel wrote a famous paper about what it is like to be a bat, to illustrate how difficult it is to see the world from a the perspective of a different species. But even if we  can’t know ‘what it is like’ to be a bat, the paper gives us some facts about life as a bat: “the majority of the bats’ sounds …. arguing over food (the loudest calls), jockeying for preferred positions in their sleeping cluster, protesting mating attempts, and arguing when perched in close proximity….they help one another, remember who does them favours, and perhaps even hold grudges if not treated fairly” (p130)

Science is now also helping us to learn more about bees. “[Bees] can differentiate not only between flowers and landscapes but even human faces, demonstrating a remarkable capacity for processing complex visual information…. while bees are generally collaborative, accurate, and efficient, they are also capable of error, robbery, cheating, and social parasitism. … the collective interactions of individual bees were strikingly similar to the interactions between our individual neurones when collectively arriving at a decision.” (p.145-146) This new knowledge has also had practical implications in ‘the Honey Bee algorithm’, which is now an integral part of the multibillion dollar cloud computer industry.

Mirror self-recognition, is seen as a proxy for self-awareness. For a long time this has been regarded as a uniquely human ability. But, as the author informs us, recent research has shown that mirror self-recognition is a trait that we share with great apes. elephants and even magpies. So, it seems that as we learn more about the species that share the planet with us, the more we learn that we are not that different after all. For example, animals share linguistic features once thought to be uniquely human: these include previously unsuspected syntax in animal and bird song, and even combinatorial processing in the vocalisations of primates and insects. 

The goal in this research field, the author points out, is not to teach other species to speak human languages, but rather to design devices that can communicate with non-humans using their own modalities of communication. Many indigenous scholars also emphasise a notion of nonhuman sentience as a cornerstone of human-nature relationships: animals, plants, and even geological features, like mountains, are known as nonhuman persons – part of an extended family, sharing ancestry and relationships.

In 2017, UNESCO introduced a resolution on the importance of sound in today’s world, which proclaims “the sound environment is a key component in the equilibrium of all human beings in their relationship with others and with the world.” (p 200). 

On an individual level we should all acknowledge that we need to re-think our attitudes to the environment we live in. As the book makes clear, we are not in any way isolated from the world around us. And with the chaos and destruction we see in parts of the world today, we should perhaps also recognise how much we can learn from animals and their way of life: they tend to be much more in harmony with nature. After all, even if we can’t know what it is like to be a bat, reading this book we can easily conclude that there are many similarities in our ways of living. And we have the means, tools and knowhow to change and improve the environment both for ourselves, the bats and all other living creatures. We owe it to them to do something before it is too late.

Published by Princeton University Press, Oxford, ISBN 978-0691206288