Preface
Humans have always been fascinated with whales and dolphins. However,
despite this centuries-long interest, the greatest strides in understanding
these animals, and their acoustic behavior, have come in the last 50 years.
However, even with numerous studies, our knowledge of the acoustic
behavior of these animals is quite limited. This limit in our knowledge
results from inherent difficulties in studying large aquatic animals that live
in an ecosystem that can be hostile to humans and extremely difficult in
which to work, especially if detailed information is desired. Indeed, even
the artificial sensors that are often used with large marine mammals tend
to have limited range and capabilities.
Clearly, the same kinds of experiments done on mice, cats, and bats are
not easily performed with marine mammals. It is very difficult and expensive to perform detailed auditory experiments with all but the smaller
dolphins and porpoises. The difficulty in working even with smaller dolphins
and porpoises in an aquatic environment cannot be emphasized enough. It
would be difficult to keep and maintain in captivity even the smallest baleen
whale, the minke whale, which can grow to a length of 10 to 12 m. Moreover, many species of whales are endangered, so that researchers are
required to obtain special permits with the provision that the animals are
protected. Rarely, if ever, can one do invasive studies of live animals.
Despite these problems, our knowledge of the bioacoustics of smaller
whales, dolphins, and porpoises has grown considerably in the past decade.
Thus it is now appropriate to compile a volume on the current understanding of acoustics of these animals. The first purpose of this volume is to
provide a broad overview of the subject. A second purpose is to introduce
marine mammal bioacoustics to investigators interested in hearing in terrestrial animals, with the intent that there be more interaction between
investigators interested in hearing by marine and terrestrial mammals.
It should be noted from the outset that the greatest amount of information in this volume deals with dolphins and small whales, the species that
make up the odontocete or toothed whales family. The lack of information
in the volume on the larger mysticete (baleen) whales is not due to lack of
xi
Humans have always been fascinated with whales and dolphins. However,
despite this centuries-long interest, the greatest strides in understanding
these animals, and their acoustic behavior, have come in the last 50 years.
However, even with numerous studies, our knowledge of the acoustic
behavior of these animals is quite limited. This limit in our knowledge
results from inherent difficulties in studying large aquatic animals that live
in an ecosystem that can be hostile to humans and extremely difficult in
which to work, especially if detailed information is desired. Indeed, even
the artificial sensors that are often used with large marine mammals tend
to have limited range and capabilities.
Clearly, the same kinds of experiments done on mice, cats, and bats are
not easily performed with marine mammals. It is very difficult and expensive to perform detailed auditory experiments with all but the smaller
dolphins and porpoises. The difficulty in working even with smaller dolphins
and porpoises in an aquatic environment cannot be emphasized enough. It
would be difficult to keep and maintain in captivity even the smallest baleen
whale, the minke whale, which can grow to a length of 10 to 12 m. Moreover, many species of whales are endangered, so that researchers are
required to obtain special permits with the provision that the animals are
protected. Rarely, if ever, can one do invasive studies of live animals.
Despite these problems, our knowledge of the bioacoustics of smaller
whales, dolphins, and porpoises has grown considerably in the past decade.
Thus it is now appropriate to compile a volume on the current understanding of acoustics of these animals. The first purpose of this volume is to
provide a broad overview of the subject. A second purpose is to introduce
marine mammal bioacoustics to investigators interested in hearing in terrestrial animals, with the intent that there be more interaction between
investigators interested in hearing by marine and terrestrial mammals.
It should be noted from the outset that the greatest amount of information in this volume deals with dolphins and small whales, the species that
make up the odontocete or toothed whales family. The lack of information
in the volume on the larger mysticete (baleen) whales is not due to lack of
xi