|Persona Digital Music |
Sounds in Nature
Sounds are used ubiquitously in the animal world to communicate. Animals listen for sounds that inform them about events happening at a distance. They make sounds to send messages to each other. If you sit anywhere in nature and listen, you begin to hear a symphony. Some sounds mark and defend territory, other sounds are mating signals, others sounds are emotional expressions, yet other sounds are warnings.
Birds sing to declare ownership of territory, to attract mates, and to send messages to family members. Wolves howl as a choir on clear moonlet nights to speak to each other and to express deep feelings. Sensitive humans who hear them sing share that deep feeling.
Sounds link animals in social groups. The continuous uttering of repetitive sounds is a common method of parent and infant communication. Infant Canada Geese, for example, emit a peeping every second or so and their parents emit a low pitch honk every four or five seconds. This auditory link is more important than a visual link in keeping the family unit together. When the geese flock flies together, there is continuous honking that links the group. Since they cannot maintain visual contact in a V- flight formation, sound communication allows the group to stay together.
As I write, the constant calling of sea gulls outside reminds me of the chatter in human groups. I can hear the persistent high-pitched peeping a young gull demanding attention and food from the adults. I know without looking that the supplicant is crouched low with his head down bobbing up and down with each cry. The sound and the behavior are always linked. This is an example of a fixed action patterns. The young gull is persistent because the adults are ignoring him. He hopes that his fixed action pattern will act as an innate releaser and an adult will feed him. However, the adults have turned off their automatic response. He is now about five months old and should be getting his own food. Adolescents of many species have difficulty making the transition to adult self-sufficiency.
Rhesus monkeys make 15 sounds that are associated with facial expressions. Monkeys in danger make short, sharp threatening calls with eyes wide, ears flat, mouth wide open. Relaxed monkeys 'coo', with lips pouting and open. Monkeys identified threat calls with facial expressions, just as human infants match voice to face, starting at two months old.
All animal share fundamental strategies of sound communication. As a rule, the meaning of sound communications is species specific, although there are some basic and old sounds that are shared among diverse animal species. Ehret and Riecke, for example, suggested that the squeaks made by baby mice in the nest are similar to human infant sounds. They found that mouse mothers react to the calls that contain word-like groups of three tones at 3.8, 7.6 and 11.4 kilohertz. The lowest frequency was the most critical as it is in human communication. It is difficult to understand a voice from which the bass frequencies have been removed. Ehret stated: "The perception of speech sounds in mammals' auditory system follows old rules."
The syntax of animal sounds is contained in rhythmic sequences of pitch and timbral changes. The sound production and reception systems in the temporal lobes of animal brains are hundreds of millions of years old and the latest developments are evolved modifications and elaborations of very old circuits.
Topics presented at Persona Digital Studio are from the book,
The Sound of Music by Stephen Gislason.
Persona Digital Studio is located on the Sunshine Coast, Sechelt, British Columbia, Canada. email Persona Mail.
Our Music catalogue includes recorded performances by the P2500 Band, Em4U, and the Persona Classical Consort.