FREE ESSAY ON DOLPHIN TALK

DOLPHIN TALK

Bottlenose dolphins are among the most vocal of the nonhuman animals and exhibit
remarkable development of the sound production and auditory mechanisms. This can be seen
in audition, which is shown in the animal's highly refined echolocation ability, and in
tightly organized schools in which they live that are made up by sound communication. In
testing the communication skills of dolphins, extensive studies have been done on vocal
mimicry, in which the animal imitates computer-generated sounds in order to test motor
control in terms of cognitive ability. Language comprehension on the other hand has been
tested through labeling of objects, which has proven to be successful regarding the
association of sound and object stimulus. The biggest question in dolphin communication,
is whether or not the species is capable of intentional communicative acts. Though
results from studies have been debatable, the key to understanding the extent to this
"language" is to determine whether they have a repertoire of grammatical rules that
generate organized sequences. In determining this, the greatest accomplishment for both
the scientist and all of humanity, would be to accomplish interspecies communication,
creating a bridge between humans and animals which could open up a new understanding of
the unknown world of wildlife. Most importantly, it is necessary to understand the
incredible aptitude of dolphin communicative skills, and the impressive intelligence the
animal possesses which allows for a great deal of intraspecies and interspecies
communication (Schusterman, Thomas, & Wood, 1986). 
The acoustical reception and processing abilities of the bottlenosed dolphins have
generally been shown to be among the most sophisticated of any animal so far examined
(Popper, 1980 as cited by Schusterman et al. 1986). In order to understand the complexity
of these highly mechanized acoustic systems, it is necessary to learn the process for
which the dolphin hears. In most water-adapted cetaceans, tissue conduction is the
primary route of sound conduction to the middle ear. The isolation of the bullae shows an
adaptation for tissue conducted sound. The lower jaw contains fat that is closely
associated with the impedance of seawater. The lower jawbone of most odontocetes becomes
broadened and quite thin posteriorly, and the fat forms an oval shape that closely
corresponds to the area of minimum thickness of the jaw. This fat body leads directly to
the bulla, producing a sound path to the ear structures located deep within the head.
Paired and single air sacs are scattered throughout the skull, which serve to channel
these tissue-conducted sounds (Popov & Supin, 1991). Other than this description, there
are still more studies needed to determine the function of the middle ear and the type of
bone conduction that occurs within the bulla.
Due to detailed audiograms, dolphins have been shown to have the ability to detect
high-frequency sounds. In an experiment by Johnson (1966) as cited in Schusterman et al.
(1986), sine-wave sounds ranging in frequency from 75 Hz to 150 Hz were presented to a
bottle-nosed dolphin. The animal was trained to swim in a stationary area within a stall
and to watch for a light to come on. Following the light presentation a sound was
sometimes presented. If the dolphin heard the sound, its task was to leave the area and
push a lever. Sound intensity levels were varied by a staircase method of 1, 2, or 3 dB
steps. The resulting audiogram, compared to the human aerial audiogram, showed that at
regions of best sensitivity for each, thresholds for human and dolphin are quite similar,
but separated by about 50 kHz in frequency, showing that the animal's inner ear function
is very similar to a human. 
The experiments done on dolphin auditory functions have generally shown a finely adapted
sound reception system. This would be expected due to the highly adapted echolocation
ability of the bottlenosed dolphin and other cetaceans. Results of work on absolute
thresholds, critical bandwidths, frequency discrimination, and sound localization all
indicate that the dolphin auditory system is at least as good or better than the human
system. This is in spite of the fact that sound travels five times as fast under water as
it does in air (Popov et al. 1991).
The bottlenosed dolphin in captivity produces two categories of vocalizations: (a)
narrow-band, frequency-varying, continuous tonal sounds referred to as "whistles" and (b)
broad-band pulsed sounds expressed as trains of very short duration clicks of varying
rates (Evans, 1967, as cited in Schusterman et al. 1986). The pulsed sounds are used for
both communication and echolocation, and the whistles are found to be used primarily for
communication (Herman & Tavolga, 1980, as cited in Schusterman et al. 1986). Descriptions
in literature emphasizing either the whistles or the pulsed sounds have led to
contradictory hypotheses concerning the communication system of the dolphin. It has been
reported that individually specific whistles often make up over 90% of the whistle
repertoire of captive bottlenosed dolphins (Popov et al. 1991). A number of observations
of apparent vocal mimicry have been made, though with no systematic investigation of the
degree of vocal flexibility. The observed variability in the whistles, combined with the
difficulty of identifying individual vocalizing dolphins in a group, has led to
speculation that the whistles might be a complex, shared system, in which specific
meanings could be assigned to specific whistles.
Consideration of vocal mimicry has been taken to understand its relation to cognitive
complexity, and to the potential use of vocal response for communication in an artificial
language. In one study done by McCowan, Hanser, & Doyle, (1999), the dolphin was able to
learn to mimic a number of computer-generated model sounds with high fidelity and
reliability. The dolphin using its whistle mode of vocalization imitated all of the
sounds, and all were distinct from the unreinforced whistles produced prior to training.
The large majority of each dolphin's whistle vocalizations were individually specific
acoustic patterns, described as a "signature whistle"; the rest of the whistles were
short chirps. The results of the mimicry training have shown that dolphins can mimic
tonal sounds with frequencies between 4 and 20 Hz. Due to this research, scientists can
now learn from these mimicry skills how to understand and develop natural communication
based on a stronger emphasis on the animal's cognitive abilities (Brecht, 1993).
In object labeling, the dolphins seemed to understand the task of associating model
sounds with displayed objects. Progress was most rapid when the model sound was always
presented at full intensity, but the probability of its being presented on any given
trial was systematically decreased over successive trials. There wasn't any confusion of
the objects themselves, but only a tendency to drift in the quality of the rendition of
the labels. This demonstration of symbolic use of vocalizations could lead to the
investigation of the potential of animals to form referential concepts, thus creating a
new understanding of dolphin communication and its uses in the wild.
The main purpose of study in dolphin language, is the interest in whether the animal's
speech is intentional communication like our own human speech. The fact that awareness as
applied to the phenomena of human communication also implies something we would not
attribute to animals-and this is the awareness that communicative acts are behaviors
about behaviors (Crook, 1983, as cited in Schusterman et al. 1986). Language, as we know
it, could not exist without the capacity for intentional communication, as all linguistic
communications are, by definition, intentional. Dolphins have been observed to have some
of these intentional communication characteristics, as their behaviors have shown in
captivity. For example, dolphins have been observed to squirt or splash water at
strangers who come near their tank. After squirting the water the dolphin will raise
itself out of the water to curiously observe what effect their behavior had on the
stranger. Although this behavior is not communitive, nonetheless, it seems to suggest
that the dolphin is aware of the effect of its behavior on others, showing that it has
the cognitive ability for intentional communication (Erickson, 1993).
Communication between humans and dolphins occurs mostly through a gestural language that
borrows some words from American Sign Language. The trainers make the gestures with big
arm movements, asking the animal to follow commands such as "person left Frisbee fetch,"
which means "bring the Frisbee on the left to the person in the pool". In one study, two
bottlenosed dolphins were tested in proficiency in interpreting gestural language signs
and compared against humans who viewed the same videos of veridical and degraded
gestures. The dolphins were found to recognize gestures as accurately as fluent humans,
and the results suggested that the dolphins had constructed an interconnected network of
semantic and gestural representations in their memory (Herman, Morrel-Samuels, & Pack,
1990). Such requests probe the dolphins understanding of word order and test the animal's
grammatical competence. It has also been determined that dolphins can form a generalized
concept about an object: they respond correctly to commands involving a hoop, no matter
whether the hoop is round, octagonal, or square. The animals seem to have a conceptual
grasp of the words they learn, showing an understanding of the core attributes of human
language, those being semantics and syntax (Erickson, 1993). Though this information
seems compelling for dolphin language abilities, to determine whether or not they are
capable of complex intentional communications, researchers must continue to investigate
their receptive capacities, and to attempt to provide them with a communication system
that would tap their productive capacities.
Is interspecies communication possible? Could we someday be having philosophical
discussions with a bottlenosed dolphin? Though these questions seem ridiculous, there was
much debate over these questions when a medical doctor named John Lilly came out with
hopeful findings of dolphin intelligence in the 1960s (Shane, 1991). In the first true
research of dolphin communication and intelligence, Lilly set out to show that through
the correlation of brain size and IQ, the bottlenose dolphin was perhaps smarter than
humans and began a growing interest in dolphins and their language through whistles.
Though dolphins are exceedingly intelligent creatures, no real scientific evidence has
yet been found to totally support the many conceptions about the animal's intelligence.
Lilly (1966) states, "A dolphin . . . naturally uses other sounds to convey and receive
'meaning': creaking for night-time and murky-water finding and recognition, putt-putting
and whistles for exchanges with other dolphins, and even air wailing to excite human
responses in the way of fish or applause. If a dolphin is copying our speech, he'll copy
that part of what he hears which in his 'language' conveys meanings." Although this
excerpt shows an incredible capability for dolphins to produce intelligent communication,
it is findings such as these, which lack scientific support and have lost credibility
among other dolphin researchers in the past few decades. Though his findings lack
support, Lilly was important in bringing forth interest among people and therefore funds
towards more scientifically based research and experiments that have helped us learn more
about communication skills and intelligence of dolphins (Tyack et al. 1989).
In order to clearly understand if dolphins are creating intentional, intelligent
communicative sounds and meanings, it is necessary to break down the vocal signals into
repertoires and analyze those individually. The breaking down of dolphin signaling into
component units has just now begun and the task will be to discover if, when, and to what
extent they structure formalized sequences of signal units. To determine whether they
have a repertoire of grammatical rules that generates organized sequences will be
difficult, and it will be necessary to obtain extended and continuous recordings.
Patterns must be found and compared to other dolphin recordings in order to obtain the
most accurate and universal findings for language among bottlenose dolphins (Herman,
Kuczjac II, & Holder, 1993). Through many more years of careful study of these sounds, it
is hopeful that our scientists can determine capacities and meanings behind dolphin
language.
Though interspecies communication seems unlikely at this point in time, through new
studies being conducted our conception of dolphins as communicative animals seems more
possible. Intentional communication through gestural understanding is the best finding so
far in the study of these intelligent animals, and leads many to believe there is a lot
more to dolphin's communication skills than has yet been uncovered. In tests done in
mimicry and labeling of objects, it seems that the capacity the bottlenose dolphin has
for learning and understanding is large enough to make taught communication a realistic
goal in the future of dolphin training. The highly specialized auditory and vocal
mechanisms of the animal have helped lead the way to a better understanding of cetacean
ear anatomy and sound production mechanisms, and these functions can now be seen as
complex structures unlike any found above water. Though more research needs to be done
before any true conclusions can be made about dolphin language, from what we do know the
bottlenose dolphin is among the most vocal of nonhuman animals and exhibits remarkable
development of sound production and auditory mechanisms (Schusterman et al. 1986). 
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