Different Types Of Vocalizations Research Articles

Comprehending Information in Acoustic Signals: AReview of Bioacoustic Studies

Development in bioacoustic studies have provided new opportunities to understand the information related with different types of vocalization produced by humans and other living organisms in different conditions. Bioacoustics not only help humans to understand the different types of hidden information present in the acoustic signals of living organisms but also assist in understanding how acoustic signals can be used in improving their health and diagnosing severe diseases easily. Bioacoustics benefit both humans and animals by decoding the relation of the acoustic signals with the behaviour of the animal and environment in which they live. Bioacoustic studies also aid in understanding the effects of anthropogenic activities on acoustic signals of other animals. Monitoring through acoustic tools is most convenient and a large number of precision tools are available in the recent times. This paper reviews the findings of bioacoustic studies published between 2000 to 2020 worldwide. Significant researches in the field of sound communication of different animal species have been cited in this review. Varied animal behaviours can be accounted for based on the sound produced by animals under different physiological state, environmental influences and human activities. Study of animal sounds may be of remarkable value from welfare and conservation perspective.

Superior Communication of Positive Emotions Through Nonverbal Vocalisations Compared to Speech Prosody

The human voice communicates emotion through two different types of vocalizations: nonverbal vocalizations (brief non-linguistic sounds like laughs) and speech prosody (tone of voice). Research examining recognizability of emotions from the voice has mostly focused on either nonverbal vocalizations or speech prosody, and included few categories of positive emotions. In two preregistered experiments, we compare human listeners’ (total n = 400) recognition performance for 22 positive emotions from nonverbal vocalizations (n = 880) to that from speech prosody (n = 880). The results show that listeners were more accurate in recognizing most positive emotions from nonverbal vocalizations compared to prosodic expressions. Furthermore, acoustic classification experiments with machine learning models demonstrated that positive emotions are expressed with more distinctive acoustic patterns for nonverbal vocalizations as compared to speech prosody. Overall, the results suggest that vocal expressions of positive emotions are communicated more successfully when expressed as nonverbal vocalizations compared to speech prosody.

Cyber-Physical System for Environmental Monitoring Based on Deep Learning.

Cyber-physical systems (CPS) constitute a promising paradigm that could fit various applications. Monitoring based on the Internet of Things (IoT) has become a research area with new challenges in which to extract valuable information. This paper proposes a deep learning classification sound system for execution over CPS. This system is based on convolutional neural networks (CNNs) and is focused on the different types of vocalization of two species of anurans. CNNs, in conjunction with the use of mel-spectrograms for sounds, are shown to be an adequate tool for the classification of environmental sounds. The classification results obtained are excellent (97.53% overall accuracy) and can be considered a very promising use of the system for classifying other biological acoustic targets as well as analyzing biodiversity indices in the natural environment. The paper concludes by observing that the execution of this type of CNN, involving low-cost and reduced computing resources, are feasible for monitoring extensive natural areas. The use of CPS enables flexible and dynamic configuration and deployment of new CNN updates over remote IoT nodes.

Comparing aerosol concentrations and particle size distributions generated by singing, speaking and breathing

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has resulted in an unprecedented shutdown in social and economic activity, with the cultural sector particularly severely affected. Restrictions on musical performances have arisen from a perception that there is a significantly higher risk of aerosol production from singing than speaking, based upon high-profile examples of clusters of COVID-19 following choral rehearsals. However, comparing aerosol generation from different types of vocalization, including singing, across a range of volumes is a rapidly evolving area of research. Here, we measured aerosols from singing, speaking and breathing from a large cohort of 25 professional singers in a range of musical genres in a zero-background environment, allowing unequivocal attribution of aerosol production to specific vocalizations. We do not assess the relative volumes at which people speak and sing. However, both showed steep increases in mass concentration with increase in loudness (spanning a factor of 20–30 across the dynamic range measured, p < 0.001). At the quietest volume (50 to 60 dBA), neither singing (p = 0.19) nor speaking (p = 0.20) were significantly different to breathing. At the loudest volume (90 to 100 dBA), a statistically significant difference (p < 0.001) was observed between singing and speaking, but with singing only generating a factor of between 1.5 and 3.4 more aerosol mass. Guidelines for musical performances should be based on the loudness and duration of the vocalization, the number of participants and the environment in which the activity occurs, rather than the type of vocalization. Mitigations such as the use of amplification and increased attention to ventilation should be employed where practicable.Copyright © 2021 American Association for Aerosol Research

A comparative characterization of laryngeal anatomy in the singing mouse.

Sexual displays are some of the most dramatic and varied behaviors that have been documented. The elaboration of such behaviors often relies on the modification of existing morphology. To understand how display elaboration arises, we analyzed the laryngeal anatomy of three species of mice that vary in the presence and complexity of their vocal displays. Mice and rats have a specialized larynx that enables them to produce both low-frequency "audible" sounds, perhaps using vocal fold vibration, as well as distinct mechanisms that are thought to enable higher frequency sounds, such as vocal membrane vibration and intralaryngeal whistles. These mechanisms rely on different structures within the larynx. Using histology, we characterized laryngeal anatomy in Alston's singing mouse (Scotinomys teguina), the northern pygmy mouse (Baiomys taylori), and the laboratory mouse (Mus musculus), which produce different types of vocalizations. We found evidence of a vocal membrane in all species, as well as species differences in vocal fold and ventral pouch size. Presence of a vocal membrane in these three species, which are not known to use vocal membrane vibration, suggests that this structure may be widespread among muroid rodents. An expanded ventral pouch in singing and pygmy mice suggests that these mice may use an intralaryngeal whistle to produce their advertisement songs, and that an expanded ventral pouch may enable lower frequencies than laboratory mouse whistle-produced sounds. Variation in the laryngeal anatomy of rodents fits into a larger pattern across terrestrial vertebrates, where the development and modification of vocal membranes and pouches, or air sacs, are common mechanisms by which vocalizations diversify. Understanding variation in the functional anatomy of relevant organs is the first step in understanding how morphological changes enable novel displays.

Crying out in pain-A systematic review into the validity of vocalization as an indicator for pain.

BackgroundVocalization is often used to assess pain, sometimes combined with other behaviours such as facial expressions. Contrary to facial expressions, however, for vocalization, there is little evidence available on the association with pain. The aim of this systematic review was to critically analyse the association between vocalization and pain, to explore if vocalizations can be used as a “stand‐alone” indicator for pain.MethodsThe search was performed according to the Prisma Guidelines for systematic reviews and meta‐analysis. The following terms were used: “Pain Measurement,” “Vocalization” and “Verbalization.” The study population included verbal and non‐verbal individuals, including older people and children. The search was performed in three different databases: PubMed, Embase and CINAHL. A total of 35 studies were selected for detailed investigation. Quality assessments were made using two grading systems: Grading of Recommendations Assessment Development and Evaluation system and the Newcastle‐Ottawa scale.ResultsAn association between vocalization and pain was found in most studies, particularly when different types of vocalizations were included in the investigation. Different types of vocalization, but also different types of pain, shape this association. The association is observed within all groups of individuals, although age, amongst others, may have an influence on preferred type of vocalization.ConclusionsThere is an association between vocalization and pain. However, vocalization as a “stand‐alone” indicator for pain indicates only a limited aspect of this multifactorial phenomenon. Using vocalization as an indicator for pain may be more reliable if other pain indicators are also taken into account.SignificanceVocalizations are frequently used in pain scales, although not yet thoroughly investigated as a “single indicator” for pain, like, e.g. facial expression. This review confirms the role of vocalizations in pain scales, and stresses that vocalizations might be more reliable if used in combination with other pain indicators.

Microstimulation in Different Parts of the Periaqueductal Gray Generates Different Types of Vocalizations in the Cat

In the cat four different types of vocalization, mews, howls, cries, and hisses were generated by microstimulation in different parts of the periaqueductal gray (PAG). While mews imply positive vocal expressions, howls, hisses, and cries represent negative vocal expressions. In the intermediate PAG, mews were generated in the lateral column, howls, and hisses in the ventrolateral column. Cries were generated in two other regions, the lateral column of the rostral PAG and the ventrolateral column of the caudal PAG. In order to define the specific motor patterns of the mews, howls, and cries, the following muscles were recorded during these vocalizations; larynx (cricothyroid, thyroarytenoid, and posterior cricoarytenoid), tongue (genioglossus), jaw (digastric), and respiration muscles (diaphragm, internal intercostal, external, and internal abdominal oblique). During these mews, howls, and cries we analyzed the frequency, intensity, activation cascades power density, turns, and amplitude analysis of the electromyograms (EMGs). It appeared that each type of vocalization consists of a specific circumscribed motor coordination. The nucleus retroambiguus (NRA) in the caudal medulla is known to serve as the final premotor interneuronal output system for vocalization. Although neurochemical microstimulation in the NRA itself also generated vocalizations, they only consisted of guttural sounds, the EMGs of which involved only small parts of the EMGs of the mews, howls, and cries generated by neurochemical stimulation in the PAG. These results demonstrate that positive and negative vocalizations are generated in different parts of the PAG. These parts have access to different groups of premotoneurons in the NRA, that, in turn, have access to different groups of motoneurons in the brainstem and spinal cord, resulting in different vocalizations. The findings would serve a valuable model for diagnostic assessment of voice disorders in humans.

Feline vocal communication.

Cat vocalizes to communicate with another and express their internal states. The vocal repertoire of the cat is wide and up to 21 different vocalizations have been described in the literatures. But it is more than probable that the repertoire contains more types of vocalizations. An ethogram was created in this paper describing the actual known vocalisations of the domestic cat based on an auditory classification. However, the audiogram allows also a visual classification which can increase the accuracy of vocalization differentiation. The classification can be risky as it is sometimes unclear if different types of vocalizations are produced in different environments or if a unique type of vocalization is used with variation in the acoustic parameters. As an example, isolation calls produced by kittens differ depending on the context. The environment has an important impact on the vocal behaviour and thus feral cats and pet cats vocalize differently. Pet cats are thus able to create an efficient communication with humans thanks to the flexibility of vocalisation behaviours. This review allowed us to create a simple model of the cat vocal repertory.

Sexual dimorphism in the loud calls of Azara's owl monkeys (Aotus azarae): evidence of sexual selection?

Primates use different types of vocalizations in a variety of contexts. Some of the most studied types have been the long distance or loud calls. These vocalizations have been associated with mate defense, mate attraction, and resource defense, and it is plausible that sexual selection has played an important role in their evolution. Focusing on identified individuals of known sex and age, we evaluated the sexual dimorphism in a type of loud calls (hoots) in a population of wild owl monkeys (Aotus azarae) in Argentina. We found evidence of sexual dimorphism in call structure, with females and males only emitting one type of call, each differing in dominant frequency and Shannon entropy. In addition, both age-related and sex-specific differences in call usage were also apparent in response to the removal of one group member. Future acoustic data will allow us to assess if there are individual characteristics and if the structure of hoot calls presents differences in relation to the social condition of owl monkeys or specific sex responses to variants of hoot calls' traits. This will provide deeper insights into the evolution of vocal mechanisms regulating pair bonding and mate choice strategies in this and other primate species.

Vocalizations Produced by Bottlenose Dolphins (Tursiops truncatus) during Mouth Actions in Aggressive and Non-aggressive Contexts

Dolphins exchange information with conspecifics using different types of vocalizations that are often associated with specific behaviors. The present study used simultaneous acoustic and video recordings of captive bottlenose dolphins (Tursiops truncatus) in Honduras to describe potential correlations between the type of mouthing behavior (open mouth, mouthing, bite) and associated vocalizations (whistle, whistle-squawk, chirp, moan, burst-pulse ‘A’, burst-pulse ‘B’, clicks). Literature on sound-behavior relationships among odontocetes with the noted infrequent systematic analyses of mouth actions highlights the need for this investigation. The influence of aggression on vocalization use was also addressed. From this observational study a series of general expectations on the interaction of sound, mouth action, and aggressive context are presented. Mouth actions are associated with vocalizations more often than not, and results suggest an overall flexible association of vocalizations during mouth actions, with the production of various sounds altered during aggressive contexts. There is an apparent distinction of frequency-modulated sounds with mouthing, suggesting that frequency parameters are an important characteristic of information exchange during mouth actions, and further that mouth actions are individually distinct behaviors. A dichotomy of burst pulse sounds in association with aggressive and non-aggressive contexts also introduces the need to analyze pulsed sounds according to inter-pulse interval. This paper proposes that there may be an interactive function to the use of vocalizations during mouth actions that is not yet understood.

Impaired generalization of speaker identity in the perception of familiar and unfamiliar voices.

In 2 behavioral experiments, we explored how the extraction of identity-related information from familiar and unfamiliar voices is affected by naturally occurring vocal flexibility and variability, introduced by different types of vocalizations and levels of volitional control during production. In a first experiment, participants performed a speaker discrimination task on vowels, volitional (acted) laughter, and spontaneous (authentic) laughter from 5 unfamiliar speakers. We found that performance was significantly impaired for spontaneous laughter, a vocalization produced under reduced volitional control. We additionally found that the detection of identity-related information fails to generalize across different types of nonverbal vocalizations (e.g., laughter vs. vowels) and across mismatches in volitional control within vocalization pairs (e.g., volitional laughter vs. spontaneous laughter), with performance levels indicating an inability to discriminate between speakers. In a second experiment, we explored whether personal familiarity with the speakers would afford greater accuracy and better generalization of identity perception. Using new stimuli, we largely replicated our previous findings: whereas familiarity afforded a consistent performance advantage for speaker discriminations, the experimental manipulations impaired performance to similar extents for familiar and unfamiliar listener groups. We discuss our findings with reference to prototype-based models of voice processing and suggest potential underlying mechanisms and representations of familiar and unfamiliar voice perception. (PsycINFO Database Record

Motor organization of positive and negative emotional vocalization in the cat midbrain periaqueductal gray.

Neurochemical microstimulation in different parts of the midbrain periaqueductal gray (PAG) in the cat generates four different types of vocalization, mews, howls, cries, and hisses. Mews signify positive vocal expression, whereas howls, hisses, and cries signify negative vocal communications. Mews were generated in the lateral column of the intermediate PAG and howls and hisses in the ventrolateral column of the intermediate PAG. Cries were generated in two regions, the lateral column of the rostral PAG and the ventrolateral column of the caudal PAG. To define the specific motor patterns belonging to mews, howls, and cries, the following muscles were recorded during these vocalizations: larynx (cricothyroid, thyroarytenoid, and posterior cricoarytenoid), tongue (genioglossus), jaw (digastric), and respiration (diaphragm, internal intercostal, external abdominal oblique, and internal abdominal oblique) muscles. Furthermore, the frequency, intensity, activation cascades, and turns and amplitude analyses of the electromyograms (EMGs) during these vocalizations were analyzed. The results show that each type of vocalization consists of a specific, circumscribed motor coordination. The nucleus retroambiguus (NRA) in the caudal medulla serves as the final premotor interneuronal output system for vocalization. NRA neurochemical microstimulation also generated vocalizations (guttural sounds). Analysis of the EMGs demonstrated that these vocalizations consist of only small parts of the emotional voalizations generated by neurochemical stimulation in the PAG. These results demonstrate that motor organization of positive and negative emotional vocal expressions are segregated in the PAG and that the PAG uses the NRA as a tool to gain access to the motoneurons generating vocalization.

Different vocal signals, but not prior experience, influence heterospecific from conspecific discrimination

Efficient communication between animals requires specificity to ensure that animals distinguish relevant signals from background noise. Research on discrimination between the acoustic signals of heterospecific versus conspecific animals, especially in birds, has focused on the songs produced by breeding males, in spite of the fact that animals produce other types of acoustic signals such as calls and duets. We used acoustic playback experiments to evaluate whether tropical white-eared ground-sparrows, Melozone leucotis , use calls, male solo songs and duets to discriminate conspecific from heterospecific competitors. We also evaluated whether prior experience influences competitors' discrimination by comparing responses among populations of white-eared ground-sparrows that are allopatric and sympatric with a congeneric competitor species (Prevost's ground-sparrows, Melozone biarcuatum ). White-eared ground-sparrows displayed more intense responses to conspecific vocalizations than they did to congeneric vocalizations. The duets produced in response to conspecific playback exhibited higher bandwidth and maximum frequency, lower minimum frequency and longer duration than duets produced in response to heterospecific playback. These results suggest that white-eared ground-sparrows use information encoded in vocalizations to discriminate competitors from noncompetitor species. The observed responses were not influenced by previous experience; white-eared ground-sparrows displayed similar responses whether they lived in sympatry or allopatry with the congener simulated through playback. Our results expand our understanding of how animals use different types of vocalizations to discriminate conspecific from heterospecific signals.

Comparison of auditory-vocal interactions across multiple types of vocalizations in marmoset auditory cortex

Auditory-vocal interaction, the modulation of auditory sensory responses during vocal production, is an important but poorly understood neurophysiological phenomenon in nonhuman primates. This sensory-motor processing has important behavioral implications for self-monitoring during vocal production as well as feedback-mediated vocal control for both animals and humans. Previous studies in marmosets have shown that a large portion of neurons in the auditory cortex are suppressed during self-produced vocalization but have primarily focused on a single type of isolation vocalization. The present study expands previous analyses to compare auditory-vocal interaction of cortical responses between different types of vocalizations. We recorded neurons from the auditory cortex of unrestrained marmoset monkeys with implanted electrode arrays and showed that auditory-vocal interactions generalize across vocalization types. We found the following: 1) Vocal suppression and excitation are a general phenomenon, occurring for all four major vocalization types. 2) Within individual neurons, suppression was the more general response, occurring for multiple vocalization types, while excitation tended to be more specific to a single vocalization type. 3) A subset of neurons changed their responses between different types of vocalization, most often from strong suppression or excitation for one vocalization to unresponsive for another, and only rarely from suppression to excitation. 4) Differences in neural responses between vocalization types were weakly correlated with passive response properties, measured by playbacks of acoustic stimuli including recorded vocalizations. These results indicate that vocalization-induced modulation of the auditory cortex is a general phenomenon applicable to all vocalization types, but variations within individual neurons suggest possible vocalization-specific coding.

The Head and Neck Muscles of the Serval and Tiger: Homologies, Evolution, and Proposal of a Mammalian and a Veterinary Muscle Ontology

Here we describe the head and neck muscles of members of the two extant felid subfamilies (Leptailurus serval: Felinae; Panthera tigris: Pantherinae) and compare these muscles with those of other felids, other carnivorans (e.g., domestic dogs), other eutherian mammals (e.g., rats, tree-shrews and modern humans), and noneutherian mammals including monotremes. Another major goal of the article is to discuss and help clarify nomenclatural discrepancies found in the Nomina Anatomica Veterinaria and in veterinary atlases and textbooks that use cats and dogs as models to understand the anatomy of domestic mammals and to stress differences with modern humans. We propose a unifying nomenclature that is expanded to all the head and neck muscles and to all mammalian taxa in order to help build veterinary and mammalian muscle ontologies. Our observations and comparisons and the specific use of this nomenclature point out that felids such as tigers and servals and other carnivorans such as dogs have more facial muscle structures related to the mobility of both the auricular and orbital regions than numerous other mammals, including modern humans, which might be the result of an ancient adaptation related to the remarkable predatory capacities of carnivorans. Interestingly, the skeletal differences, mainly concerning the hyoid apparatus, pharynx, and larynx, that are likely associated with the different types of vocalizations seen in the Felinae (mainly purring) and Pantherinae (mainly roaring) are not accompanied by clear differences in the musculature connected to these structures in the feline L. serval and the pantherine P. tigris.

Female presence and estrous state influence mouse ultrasonic courtship vocalizations.

The laboratory mouse is an emerging model for context-dependent vocal signaling and reception. Mouse ultrasonic vocalizations are robustly produced in social contexts. In adults, male vocalization during courtship has become a model of interest for signal-receiver interactions. These vocalizations can be grouped into syllable types that are consistently produced by different subspecies and strains of mice. Vocalizations are unique to individuals, vary across development, and depend on social housing conditions. The behavioral significance of different syllable types, including the contexts in which different vocalizations are made and the responses listeners have to different types of vocalizations, is not well understood. We examined the effect of female presence and estrous state on male vocalizations by exploring the use of syllable types and the parameters of syllables during courtship. We also explored correlations between vocalizations and other behaviors. These experimental manipulations produced four main findings: 1) vocalizations varied among males, 2) the production of USVs and an increase in the use of a specific syllable type were temporally related to mounting behavior, 3) the frequency (kHz), bandwidth, and duration of syllables produced by males were influenced by the estrous phase of female partners, and 4) syllable types changed when females were removed. These findings show that mouse ultrasonic courtship vocalizations are sensitive to changes in female phase and presence, further demonstrating the context-sensitivity of these calls.

Vocalizations of infants (9—11 months old) in response to musical and linguistic stimuli

This study analyzes infant vocal responses in order to determine whether infants exposed to both linguistic and musical stimuli exhibit different types of vocalizations in response to those two different kinds of stimulation. Twenty-one infants, from 9 to 11 months of age, were observed in four weekly sessions over the period of a month. Each session consisted of two presentations: musical, in which the experimenter sang, and linguistic, in which the experimenter narrated poems. Infants’ vocalizations were recorded and submitted to aural and acoustic analysis. The results showed that infants’ vocalizations in response to both presentations displayed different characteristics of duration and vocal extension. Infant vocalizations in response to musical stimuli consisted predominantly of isolated sounds, with a high percentage of first and third steps of the scale of the musical stimuli as well as a predominance of melodic intervals and contours outlining important scalar steps of the stimuli. Descending intervals were also a characteristic of infant vocal production in response to musical stimuli.

Development of echolocation and communication vocalizations in the big brown bat, Eptesicus fuscus

Big brown bats form large maternity colonies of up to 200 mothers and their pups. If pups are separated from their mothers, they can locate each other using vocalizations. The goal of this study was to systematically characterize the development of echolocation and communication calls from birth through adulthood to determine whether they develop from a common precursor at the same or different rates, or whether both types are present initially. Three females and their six pups were isolated from our captive breeding colony. We recorded vocal activity from postnatal day 1 to 35, both when the pups were isolated and when they were reunited with their mothers. At birth, pups exclusively emitted isolation calls, with a fundamental frequency range <20 kHz, and duration >30 ms. By the middle of week 1, different types of vocalizations began to emerge. Starting in week 2, pups in the presence of their mothers emitted sounds that resembled adult communication vocalizations, with a lower frequency range and longer durations than isolation calls or echolocation signals. During weeks 2 and 3, these vocalizations were extremely heterogeneous, suggesting that the pups went through a babbling stage before establishing a repertoire of stereotyped adult vocalizations around week 4. By week 4, vocalizations emitted when pups were alone were identical to adult echolocation signals. Echolocation and communication signals both appear to develop from the isolation call, diverging during week 2 and continuing to develop at different rates for several weeks until the adult vocal repertoire is established.

The developmental ecology of acoustic reactions: approaches to song playbacks by male cowbirds change across their first year of life

We examined whether captive, wild-caught juvenile male cowbirds (Molothrus ater) would react to playbacks of vocalizations of conspecifics and heterospecifics and if so, whether those reactions would vary across development. We played five different types of vocalizations to juveniles: adult male cowbird song, adult female cowbird chatter, juvenile male cowbird plastic song, songs from species that are common cowbird hosts, and songs of species that cowbirds do not parasitize. We played the vocalizations to different groups of juvenile males at four times during their first year of life (summer, autumn, winter, and spring). Juveniles approached the playback speaker in response to broadcasts of specific vocalizations, but these responses differed across the seasons. Early in summer, young males approached the speaker more often when adult conspecific vocalizations were played. In the autumn, subjects approached the speaker more often during broadcasts of juvenile cowbird plastic song. In the winter, juveniles approached conspecific and heterospecific vocalizations equally. In the spring, they once again approached adult conspecific vocalizations more than any others. Also, only in the spring, the time subjects spent near the speaker during the male cowbird song playbacks was positively related to the song's attractiveness to females (its ability to elicit copulation solicitation displays from females). These responses suggest that song reactivity may serve several functions across development, including species recognition, song learning, and group organization.

The Humpback Whale Acoustic Research Collaboration studies on the use of sound by humpback whales

Humpback whales produce two different types of vocalizations with apparent difference functions: songs and social sounds. There is also the potential to use the sounds of their environment, such as surf noise during migration along coasts, though this has not been demonstrated. The Humpback Whale Acoustic Research Collaboration (HARC) is a series of well-controlled, multiplatform experiments designed to improve our understanding of how humpback whales use sound, both vocalizations and sounds of their environment. There have been two major experiments with humpback whales migrating along the east coast of Australia. Whales passing within 10 km were tracked acoustically and visually during daylight hours in conjunction with behavioral observations, and DTAGs were used on some whales to record their 3D movements and the sound field to which they were exposed. There was also playback of social sounds and full characterization of the acoustics of the environment, including the ambient noise exposure. Preliminary results of interactions between singing and nonsinging whales, the use of song as a spacing mechanism, responses to playback, and context of social sounds will be discussed. [Research supported by ONR and DSTO.]