Variation in the vocal behavior of nonhuman vertebrates includes graded transitions and more dramatic changes.Wapiti males produce a reproductive bugle that has a fundamental frequency that surpasses 2,000 Hz with evi...Variation in the vocal behavior of nonhuman vertebrates includes graded transitions and more dramatic changes.Wapiti males produce a reproductive bugle that has a fundamental frequency that surpasses 2,000 Hz with evidence of biphonation and other nonlinear phenomena.Here,we analyze the acoustic structure of captive wapiti vocalizations to compare the male bugle with 3 categories of distress vocalizations:neonate distress(capture)calls,calf isolation calls,and adult female isolation calls.These 4 high-arousal call categories serve a common general function in recruiting conspecifics but occur in different behavioral contexts(capture,isolation,reproduction).Our goal was to distinguish characteristics that vary in graded steps that may correspond to an animal’s age or size from characteristics that are unique to the bugle.Characteristics of the high and loud fundamental(G0)varied in an age/size-graded manner with a decrease in minimum G0,an increase in the maximum and range of G0,with no evidence of sex differences.The nonlinear phenomena of deterministic chaos,biphonation,and frequency jumps were present in all 4 call categories and became more common from the distress vocalizations of neonates to calves to adult females to the male bugle.Two temporal characteristics sharply distinguished the bugle from the 3 categories of distress vocalizations:these included a prolonged call duration and a maximum G0 that occurred much later in the call for the bugle than for distress vocalizations.Our results suggest that distress vocalizations of different age groups and the reproductive bugle of wapiti share a high G0,with age/size-graded changes in G0 and nonlinear phenomena,but differ sharply in temporal characteristics.展开更多
In contrast to the cries of human infants, sounds made by non-human infants in different stressful behavioral contexts （hunger or physical discomfort, isolation, capture by humans or predators） are usually treated a...In contrast to the cries of human infants, sounds made by non-human infants in different stressful behavioral contexts （hunger or physical discomfort, isolation, capture by humans or predators） are usually treated as distinct types of vocalizations. However, if distress vocalizations produced by different species and in different contexts share a common motivational state and associated neurochemical pathways, we can expect them to share a common acoustic structure and adaptive function, showing only limited variation that corresponds to the infant＇s level of arousal. Based on this premise, we review the acoustic structure and adaptive function of two types of distress calls, those given when infants were isolated from their mothers （isolation caUs） or captured by humans （capture calls）. We conducted a within-context comparison examining the two call types across a diverse se- lection of mammalian species and other vertebrate groups, followed by a comparison of how acoustic structure and function dif- fers between these contexts. In addition, we assessed acoustic traits that are critical to the response of caregivers. Across verte- brate species, distress vocalizations produced in these two behavioral contexts tend to be tonal with a simple chevron, flat or de- scending pattern of frequency modulation. Reports that both isolation and capture calls of vertebrate infants serve to attract care- givers are universal, and the fundamental frequency of infant vocalizations is often critical to this response. The results of our re- view are consistent with the hypothesis that differences in the acoustic structure of isolation and capture distress vocalizations re- flect differences in arousal, and not discrete functions. The similarity in acoustic structure and caregiver response observed across vertebrates adds support to the hypothesis that the production and processing of distress vocalizations are part of a highly-conserved system of social vocal behaviour in vertebrates. Bioacoustic research may move forward by recognizing the commonality among different forms of infant solicitations that attract caregivers, and the commonality of these solicitations with vocalizations that attract conspecifics in still other behavioral contexts [Current Zoology 58 （5）： 698-726, 2012].展开更多
基金The University of Winnipeg and The University of Winnipeg Foundation contributed funding to this research.
文摘Variation in the vocal behavior of nonhuman vertebrates includes graded transitions and more dramatic changes.Wapiti males produce a reproductive bugle that has a fundamental frequency that surpasses 2,000 Hz with evidence of biphonation and other nonlinear phenomena.Here,we analyze the acoustic structure of captive wapiti vocalizations to compare the male bugle with 3 categories of distress vocalizations:neonate distress(capture)calls,calf isolation calls,and adult female isolation calls.These 4 high-arousal call categories serve a common general function in recruiting conspecifics but occur in different behavioral contexts(capture,isolation,reproduction).Our goal was to distinguish characteristics that vary in graded steps that may correspond to an animal’s age or size from characteristics that are unique to the bugle.Characteristics of the high and loud fundamental(G0)varied in an age/size-graded manner with a decrease in minimum G0,an increase in the maximum and range of G0,with no evidence of sex differences.The nonlinear phenomena of deterministic chaos,biphonation,and frequency jumps were present in all 4 call categories and became more common from the distress vocalizations of neonates to calves to adult females to the male bugle.Two temporal characteristics sharply distinguished the bugle from the 3 categories of distress vocalizations:these included a prolonged call duration and a maximum G0 that occurred much later in the call for the bugle than for distress vocalizations.Our results suggest that distress vocalizations of different age groups and the reproductive bugle of wapiti share a high G0,with age/size-graded changes in G0 and nonlinear phenomena,but differ sharply in temporal characteristics.
文摘In contrast to the cries of human infants, sounds made by non-human infants in different stressful behavioral contexts （hunger or physical discomfort, isolation, capture by humans or predators） are usually treated as distinct types of vocalizations. However, if distress vocalizations produced by different species and in different contexts share a common motivational state and associated neurochemical pathways, we can expect them to share a common acoustic structure and adaptive function, showing only limited variation that corresponds to the infant＇s level of arousal. Based on this premise, we review the acoustic structure and adaptive function of two types of distress calls, those given when infants were isolated from their mothers （isolation caUs） or captured by humans （capture calls）. We conducted a within-context comparison examining the two call types across a diverse se- lection of mammalian species and other vertebrate groups, followed by a comparison of how acoustic structure and function dif- fers between these contexts. In addition, we assessed acoustic traits that are critical to the response of caregivers. Across verte- brate species, distress vocalizations produced in these two behavioral contexts tend to be tonal with a simple chevron, flat or de- scending pattern of frequency modulation. Reports that both isolation and capture calls of vertebrate infants serve to attract care- givers are universal, and the fundamental frequency of infant vocalizations is often critical to this response. The results of our re- view are consistent with the hypothesis that differences in the acoustic structure of isolation and capture distress vocalizations re- flect differences in arousal, and not discrete functions. The similarity in acoustic structure and caregiver response observed across vertebrates adds support to the hypothesis that the production and processing of distress vocalizations are part of a highly-conserved system of social vocal behaviour in vertebrates. Bioacoustic research may move forward by recognizing the commonality among different forms of infant solicitations that attract caregivers, and the commonality of these solicitations with vocalizations that attract conspecifics in still other behavioral contexts [Current Zoology 58 （5）： 698-726, 2012].
