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w.w.L. Au
the wild. Do they echolocate for navigation purposes in enclosed bays,
swamps, and in transiting open bodies of water? If so, how often do they
echolocate daily? Do they usually use their echolocation for the detection
of predators and prey, or do they rely on their excellent hearing capabilities? If they echolocate to detect predators and prey, what kind of strategies are normally implemented? Are their echolocation abilities used in
long range detection (greater than approximately 100m) or for short ranges
of 20m or less? Dolphins normally exist in pods of several animals to
several hundred animals. How is echolocation used in a group of animals?
Do the individuals in a pod echolocate independently of each other, does
the leader of the pod usually assume the responsibility of probing the immediate environment, or is that duty relegated to another animal? It would
not be surprising if dolphins echolocate mainly at night or when in very
turbid waters and use their vision and hearing during the day. In what
kinds of sonar discrimination problems are dolphins typically involved?
What is the social implication of echolocation and how is it used in a social
context?
The questions in the previous paragraph are some of the more obvious
ones that pertain to the use of echolocation in nature. There are many more
valid and interesting questions. However, given the difficulties of performing research with wild dolphins, some of these questions will probably never
be answered satisfactorily. To make continual progress in this area,
researchers must become more sophisticated and take advantage of
advances in technology. One area of particular importance is the development of miniature computer-controlled systems. These can be used to
control instrumentation packages that can be attached to wild dolphins to
monitor echolocation activities and telemeter data via satellite links. The
problems of working with wild dolphins are so difficult that only through
innovation and creativity will we be able to make significant advances in
our knowledge.
References
Albers VM (1965) Underwater Acoustics Handbook II. University Park, PA: Pennsylvania States University Press.
Aroyan JL (1996) Three-dimensional numerical simulation of biosonar signal emission and reception in the common dolphin. Ph.D. Dissertation, University of
California, Santa Cruz.
Aroyan JL, Cranford TW, Kent J, Norris KS (1992) Computer modeling of acoustic
beam formation in Delphinus delphis. J Acoust Soc Am 95:2539-2545.
Au WWL (1980) Echolocation signals of the Atlantic bottlenose dolphin (Tursiops
truncatus), in Open Waters. In: Busnel RG, Fish JF (eds) Animal Sonar Systems.
New York: Plenum Press, pp. 251-282.
Au WWL (1992) Application of the reverberation-limited form of the sonar equation to dolphin echolocation. J Acoust Soc Am 92:1822-1826.
Au WWL (1993) The Sonar of Dolphins. New York: Springer-Verlag.
w.w.L. Au
the wild. Do they echolocate for navigation purposes in enclosed bays,
swamps, and in transiting open bodies of water? If so, how often do they
echolocate daily? Do they usually use their echolocation for the detection
of predators and prey, or do they rely on their excellent hearing capabilities? If they echolocate to detect predators and prey, what kind of strategies are normally implemented? Are their echolocation abilities used in
long range detection (greater than approximately 100m) or for short ranges
of 20m or less? Dolphins normally exist in pods of several animals to
several hundred animals. How is echolocation used in a group of animals?
Do the individuals in a pod echolocate independently of each other, does
the leader of the pod usually assume the responsibility of probing the immediate environment, or is that duty relegated to another animal? It would
not be surprising if dolphins echolocate mainly at night or when in very
turbid waters and use their vision and hearing during the day. In what
kinds of sonar discrimination problems are dolphins typically involved?
What is the social implication of echolocation and how is it used in a social
context?
The questions in the previous paragraph are some of the more obvious
ones that pertain to the use of echolocation in nature. There are many more
valid and interesting questions. However, given the difficulties of performing research with wild dolphins, some of these questions will probably never
be answered satisfactorily. To make continual progress in this area,
researchers must become more sophisticated and take advantage of
advances in technology. One area of particular importance is the development of miniature computer-controlled systems. These can be used to
control instrumentation packages that can be attached to wild dolphins to
monitor echolocation activities and telemeter data via satellite links. The
problems of working with wild dolphins are so difficult that only through
innovation and creativity will we be able to make significant advances in
our knowledge.
References
Albers VM (1965) Underwater Acoustics Handbook II. University Park, PA: Pennsylvania States University Press.
Aroyan JL (1996) Three-dimensional numerical simulation of biosonar signal emission and reception in the common dolphin. Ph.D. Dissertation, University of
California, Santa Cruz.
Aroyan JL, Cranford TW, Kent J, Norris KS (1992) Computer modeling of acoustic
beam formation in Delphinus delphis. J Acoust Soc Am 95:2539-2545.
Au WWL (1980) Echolocation signals of the Atlantic bottlenose dolphin (Tursiops
truncatus), in Open Waters. In: Busnel RG, Fish JF (eds) Animal Sonar Systems.
New York: Plenum Press, pp. 251-282.
Au WWL (1992) Application of the reverberation-limited form of the sonar equation to dolphin echolocation. J Acoust Soc Am 92:1822-1826.
Au WWL (1993) The Sonar of Dolphins. New York: Springer-Verlag.