5
Acoustics and Social Behavior
of Wild Dolphins: Implications for
a Sound Society
DENISE L. HERZING
1. Introduction
Understanding and documenting the characteristics and features of the
social sounds and associated behavior of free-ranging delphinids has historically been limited by lack of access to animals and poor underwater
viewing conditions. Communication studies of delphinids have been undertaken in both captivity (see Herman and Tavolga 1980 for review) and
in the wild (Connor et al. 1992; Norris et al. 1994). Even with a wealth
of information about dolphin sound production and hearing capabilities
from captivity, there are significant gaps in understanding how dolphins
detect, decode, and decipher both their environmental and social signals
in the wild. Although the abilities of dolphins to actively produce both
echolocation signals and social sounds have been documented, little is
understood about the sensory exposure and information available to,
and utilized by, free-ranging delphinids. One way to address this issue
is to review the use of conspecific social signals and behavior. Dolphins,
like other animals, have been under evolutionary pressures for increased
efficiency in their communication system. By observing critical environmental and social aspects of delphinid society we might gain insight
into how these animals learn and selectively filter information in their
environment.
This chapter will outline the characteristics of social sounds and associated behavior of delphinids, specifically Stenella frontalis, the Atlantic
spotted dolphin, and Tursiops truncatus, the bottlenose dolphin. These two
species have been the focus of a long-term, underwater natural history study
in the Bahamas. The major emphasis of this chapter will be on the available information in the dolphin's environment, the contextual use of conspecific vocalizations, developmental behavior, and low-frequency (but
sometimes significant event) behavior. Potentially valuable future lines of
inquiry into delphinid communication and hearing will be discussed in the
last section.
225
Acoustics and Social Behavior
of Wild Dolphins: Implications for
a Sound Society
DENISE L. HERZING
1. Introduction
Understanding and documenting the characteristics and features of the
social sounds and associated behavior of free-ranging delphinids has historically been limited by lack of access to animals and poor underwater
viewing conditions. Communication studies of delphinids have been undertaken in both captivity (see Herman and Tavolga 1980 for review) and
in the wild (Connor et al. 1992; Norris et al. 1994). Even with a wealth
of information about dolphin sound production and hearing capabilities
from captivity, there are significant gaps in understanding how dolphins
detect, decode, and decipher both their environmental and social signals
in the wild. Although the abilities of dolphins to actively produce both
echolocation signals and social sounds have been documented, little is
understood about the sensory exposure and information available to,
and utilized by, free-ranging delphinids. One way to address this issue
is to review the use of conspecific social signals and behavior. Dolphins,
like other animals, have been under evolutionary pressures for increased
efficiency in their communication system. By observing critical environmental and social aspects of delphinid society we might gain insight
into how these animals learn and selectively filter information in their
environment.
This chapter will outline the characteristics of social sounds and associated behavior of delphinids, specifically Stenella frontalis, the Atlantic
spotted dolphin, and Tursiops truncatus, the bottlenose dolphin. These two
species have been the focus of a long-term, underwater natural history study
in the Bahamas. The major emphasis of this chapter will be on the available information in the dolphin's environment, the contextual use of conspecific vocalizations, developmental behavior, and low-frequency (but
sometimes significant event) behavior. Potentially valuable future lines of
inquiry into delphinid communication and hearing will be discussed in the
last section.
225