Messages from the Deep Read Online Free PDF

ways, at varying times. The songs can
be sent over huge distances, especially at the level of the deep
sound channel, about one kilometre deep.
    Dolphins can redirect the attention of
another dolphin by using an acoustic ‘flashlight’, which is like
pointing to indicate something. They can learn human sign language,
including a long sentence of four or five instructions, and can
understand chronological order. They can categorise objects through
visual and acoustic discrimination and matching.
    In an experiment, they took the same time as
humans to learn what was required, which was to produce novel
behaviour, and clearly showed self-awareness.
    How do you learn whale and dolphin languages,
and when will we be able to talk to them?
    Cracking the codes of cetacean languages and
communications has been an arduous process. As dolphins have lived
in captivity in dolphinaria for many decades, and as we have
formulated increasingly sophisticated theories about the content of
their communications, we have had a much better idea of the
meanings of dolphin sounds than of whale sounds.
    For example, if a single captive dolphin in a
group is instructed to do something, whether verbally or in sign
language, it tends to repeat or pass on that instruction to the
other dolphins in ‘delphinese’, enabling us to make an educated
guess about the meanings of the sounds used. We could then look for
these sounds in other communications and see if they mean the same
things, thus gradually building up a vocabulary.
    While dolphins can roughly copy some human
sounds and understand the meanings of the words they form, and
therefore they can converse with us to a limited extent, the
converse is usually not true — our attempts to copy dolphin sounds
do not get us too far, as the dolphins usually greet these attempts
with contempt, judging by the snorting and spitting sounds that
follow.
    This difference in ability to copy sounds and
words led some in the past to believe that, instead of us battling
to learn delphinese and whale language, we should rather
concentrate on captive dolphins and teach them to communicate with
us in English. Maybe then they could teach us dolphin language and
thinking, and maybe also how to understand whales.
    However, Robert Stenuit, in ‘The Dolphin,
Cousin to Man’ (1968), expressed it succinctly:
    “All researchers today agree that the future
of cetacean sonar research does not lie in the tanks of
institutions.
    To make a serious study of marine mammals it
is necessary to study them in their natural environment, in the
sea. In captivity animals do not use their total normal vocabulary
nor the full reach of their sonar; moreover, the echoes sent back
by the walls of the tanks confuse the recordings.”
    It must be noted that dolphins, while having
a larynx, have no vocal cords, flexible tongue or lips as we have
for speech, so they cannot correctly reproduce human sounds.
However, they have a range of sound frequencies so wide that we
need sophisticated electronic equipment to record and analyse them
for us.
    So, research became more focused on
collecting high-quality data with cameras and hydrophone and air
sound recorders to capture the images and sounds of passing
dolphins. Boats were and still are used as they can get close
enough for you to get clear recordings, but the engine noise and
the fact that you are intruding in the dolphins’ space could easily
change their natural behaviour. To counter this, hydrophones, which
are under-water microphones, have been placed in areas where
cetaceans often visit or pass by. If you can have simultaneous
sightings with clear images to accurately identify individuals, you
can then link the sounds recorded to specific subjects.
    Some studies have used trained dolphins who
co-operate with researchers in the open sea and may interact with
other dolphins.
    The U.S. Navy has been doing this off the
Bahamas in a specially-equipped boat called Sea Hunter. Some
subjects have