The Garden of Eaden: HOW DO DOLPHINS COMMUNICATE?

CLICK HERE FOR THE NEW 'GARDEN OF EADEN’ WEBSITE AND SEED SHOP

Dolphins are arguably the best known and loved of all the marine mammals. However, many aspects of the dolphins way of life still remain a mystery. Be that as it may, dolphins have been the subject of scientific research for decades and so at least there are some areas of dolphin behaviour that we do know of. One area in particularly has attracted significant investigation and that is regarding the language of dolphins.

Dolphin communication

Dolphins are capable of making a broad range of sounds using nasal airsacs located just below the blowhole. There are roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating specialised connective tissue - similar to how human vocal cords function, and through burst-pulsed sounds. However, the nature and extent of that ability is not known.

The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Amazingly, dolphin echolocation clicks are amongst the loudest sounds made by marine animals!

In 2011 researchers in the United States and Great Britain have been using a CymaScope to find out more - a CymaScope is an instrument which produces visible patterns from sound. They have found that part of dolphin communication consists of receiving and transmitting sound pictures. It is almost certain that to this ability is shared by the entire dolphin family.

Can humans communicate with dolphins?

Scientists such as John Lilly have been working with captive bottlenose dolphins since the early 1960s. Even then, it was thought that it would be only a few years before there was a communication breakthrough.

Impressed with their large brains, Lilly performed many audio experiments in order to attempted to show that dolphins were communicating with each other. In an effort to enhance human dolphin communication, he began to use computers to translate human words into dolphin whistles and to send messages back. Unfortunately,much of his experimental work has never been published.

In one Lilly experiment, a woman lived in a pool with a bottlenose dolphin named Peter as her only companion for several months. Sleeping in a bed above the pool, she was ever on call. Communication attempts were often transing sessions, where the woman attempted to teach language to the dolphin. Peter was reportedly a demanding 'roommate', and the woman eventually withdrew from the project. While a basic communication did develop, reportedly similar to that between a dog and a human, deeper exchanges - of dolphin whistles or human words - did not occur.

Lilly's work ended in the 1980s. Since then, researchers led by Louis M. Herman have developed a new approach to communication studies with captive bottlenose dolphins at the University of Hawaii. Their goals have been to discover how dolphins process information - both through sight and sound, how they learn, and how they communicate. Herman's research has verified earlier findings that dolphins have good memories and can mimic a wide variety of sounds. Able to store new information, they can also quickly update old information.

In one experiment, Herman played up to eight different short sounds on an underwater speaker in the dolphin's tank. Then another sound was played, sometimes one of the previous eight, sometimes an entirely new sound. The dolphin had to decide whether it had heard the sound before. About 70 percent of the time, the dolphin responded correctly. If the list was shortened, however, to one or two sounds, the results were 90 percent correct. Like humans given such tests, the dolphins found the recent items easiest to remember.

The dolphin's most impressive accomplishment is its ability to understand sentences expressed in either an artificial acoustic or a visual language. In the experiments, the "words" of the language are sounds generated by a computer and broadcast via an underwater speaker. First the dolphin learns words such as fetch, ball and hoop. The words refer to (1) objects in the tank; (2) actions that might be taken in connection with the objects; and (3) modifiers of place or location. In "sentences" of two or more words, the dolphin is then told to do something. The level of understanding is measured by the accuracy and reliability with which the dolphin carries out the instruction.

Dolphins perform very well on such tests. To more than 600 two-word sentence instructions, the dolphins gave correct responses about 80 percent of the time. They also understood "new" instructions almost as well as familiar ones, with only a slight advantage to the familiar. New instructions consisted of fresh combinations of words that either obeyed the language rules or, in a few cases, were logical extensions of existing rules.