Evidence of stereotyped contact call use in narwhal (Monodon monoceros) mother-calf communication (original) (raw)
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Mother–Calf vocal communication in Atlantic walrus: a first field experimental study
Animal Cognition, 2010
In all colonial pinnipeds studied, mother-young vocal recognition exists and allows rapid and reliable meetings in spite of the confusing environment of the breeding colony. The eYciency of this recognition process guarantees pup survival, especially in species where females alternate foraging sea trips and lactation periods on land. The Atlantic Walrus (Odobenus rosmarus rosmarus) is a highly gregarious pinniped with females attending their calves for an extended period of time (2-3 years). Although we expect mother-calf vocal recognition to occur in this species due to the high density of individuals packed in herds, it has never been experimentally demonstrated. Here, we assessed the individual stereotypy of both mother and calf barks recorded in the wild by measuring frequency and temporal acoustic parameters. Both discriminant function and artiWcial neural network analyses resulted in high correct classiWcation rates, underlying a well-deWned individual stereotypy in parameters related to frequency modulation and frequency values. Playback experiments showed that mothers were more responsive to the barks of their own calf than to those of unrelated young. Finally, propagation experiments revealed that barks propagate at greater distances over water surface than over ice, acoustic features such as frequency modulation and frequency spectrum being highly resistant to degradation during propagation. Thus, acoustic analysis and propagation experiments suggest that these frequency parameters might be the key acoustic features involved in the individual identiWcation process. This experimental study clearly demonstrates that Atlantic walrus has developed a highly reliable mother-calf vocal communication allowing such strong social bond.
2010
Contact calls are ubiquitous in social birds and ma mmals. Belugas are among the most vocal of cetaceans, but the function of their calls is poorl y understood. In a previous study we hypothesized that a broad band pulsed call type labeled “Type A, ” serves as a contact call between mothers and their calves. Here we examined context-specific use of call types recorded from a captive beluga social group at the Vancouver Aquarium, and found that the Type A call comprised 24% to 97% of the vocalizations during isolation, births, death o f a calf, presence of external stressors, and re-un ion of animals after separation. In contrast it compris ed 4.4% of the vocalizations produced during regular sessions. We grouped 2835 Type A calls into five variants, A1 to A5. A discriminant function analysis classified 87% of calls in the same groupi ngs that we assigned them to by ear and visual examination of spectrograms. The variants do not re present individual signatures. One variant, A1, was ...
Domestic Calves (Bos taurus) Recognize their Own Mothers by Auditory Cues
Ethology, 2010
The goal of this study was to determine if auditory cues are important in maternal recognition by domestic cattle calves, Bos taurus. Cows and their calves were separated and the vocalizations of the mothers were recorded. During experimental playbacks in a test enclosure, each calf (n = 9) was given a choice between a tape‐recorded vocalization of its mother and that of a strange mother. Calves significantly preferred their own mother's vocalization as compared to the vocalization of the unfamiliar mother. Calves spent significantly more time near the speaker that played their own mother's call, and approached significantly closer to their mother's speaker. These results demonstrate that 3–5‐wk‐old calves can recognize their mothers by auditory cues alone. Visual inspection of audiospectrograms of the cows' vocalizations suggests that there are individual differences among cows.
Frontiers in zoology, 2015
In most species, acoustical cues are crucial for mother-offspring recognition. Studies of a few species of ungulates showed that potential for individual recognition may differ between nasal and oral contact calls. Vocalizations of 28 hinds and 31 calves of farmed Iberian red deer (Cervus elaphus hispanicus) were examined with discriminant function analyses (DFA) to determine whether acoustic structure of their oral and nasal contact calls encodes information about the caller's identity. Contact calls were elicited by brief separation of individually identified animals by a distance over 10 m or by a bar fence. Both oral and nasal calls of both hinds and calves showed high potential to discriminate individuals. In hinds, individuality was significantly higher in the oral than in the nasal calls, whereas in calves, individuality was equally well expressed in both oral and nasal calls. For calves, the maximum fundamental frequency was higher and the duration was longer in oral cal...
Vocal Development in a Beluga Calf (<I>Delphinapterus leucas</I>)
Aquatic Mammals, 2008
Acoustic communication is central to the socioecology of cetaceans. Knowledge of the ontogeny of their extensive repertoires is scant, and even less is known about the role of learning in vocal development. To examine these issues, the development of calls of one male beluga (Delphinapterus leucas) calf was systematically studied at the Vancouver Aquarium throughout his first year of life and opportunistically through his second and third years. He vocalized within the first hour after birth, producing exclusively low energy, broadband pulse trains. Both the dominant frequency and the pulse repetition rate of the pulsed calls increased with age. He acquired rudimentary whistles at 2 wks of age. During the second month, whistle production increased substantially. Whistle dominant frequency tended to increase with age, and at least in his first year, whistles did not attain full stereotypy. The calf started using mixed call types consistently at 4 mo. While some sounds tended to be more variable at later ages, his mixed calls progressively lost variability and increasingly resembled his mother's most predominant stereotyped mixed call type. By 20 mo, this call type was fully stereotyped. Six months after he was exposed to his father's sounds, he incorporated one of his father's call types into his repertoire. These findings are discussed in light of current theories of sound production mechanisms in odontocetes, developmental stages of vocal acquisition, and vocal learning.
Acoustic cues to caller identity in lemurs: a case study
Journal of ethology, 2012
This study investigated the acoustic structure of grunt vocalizations in red-bellied lemurs (Eulemur rubriventer) and its potential for individual discrimination. Acoustic analyses were performed on 1,605 grunts recorded from seven lemurs belonging to two captive groups. From the perspective of sound-filter theory, we described the acoustic structure of grunts, measuring two sets of parameters: fundamental frequency characteristics as larynx-related variables and four formant frequencies as filterrelated features. Formants were effective in assigning 80.5% of the vocalizations to the correct emitter against 24.9% scored by the model based on larynx-related variables. We concluded that vocal tract resonances might potentially provide conspecifics with individual cues.
Infant Response to Mother Call Patterns in Otolemur garnettii
Folia Primatologica, 2003
Garnett's greater bushbaby infants vocalize in apparent response to their mother's contact calls. However, it remains unclear whether specific vocal or behavioral patterns by a mother elicit this vocal response. We video-recorded the behaviors and vocalizations of 4 individual mother-infant groups (mother with twins), analyzed vocalizations via spectrography and documented behaviors of mothers and infants. Initial analyses of all groups revealed that short growls and short growl bouts (or chains), but not long growls, emitted by mothers, were followed by infant clicks within 5 s. Further statistical examination of 1 mother-infant group revealed that an infant's vocal response is conditional on the sequencing of the mother's short growls and somewhat conditional on the mother's behavior before or after the short growls.
Vocal Development in a Beluga Calf ( Delphinapterus leucas
Aquatic Mammals, 2008
Acoustic communication is central to the socioecology of cetaceans. Knowledge of the ontogeny of their extensive repertoires is scant, and even less is known about the role of learning in vocal development. To examine these issues, the development of calls of one male beluga (Delphinapterus leucas) calf was systematically studied at the Vancouver Aquarium throughout his first year of life and opportunistically through his second and third years. He vocalized within the first hour after birth, producing exclusively low energy, broadband pulse trains. Both the dominant frequency and the pulse repetition rate of the pulsed calls increased with age. He acquired rudimentary whistles at 2 wks of age. During the second month, whistle production increased substantially. Whistle dominant frequency tended to increase with age, and at least in his first year, whistles did not attain full stereotypy. The calf started using mixed call types consistently at 4 mo. While some sounds tended to be more variable at later ages, his mixed calls progressively lost variability and increasingly resembled his mother's most predominant stereotyped mixed call type. By 20 mo, this call type was fully stereotyped. Six months after he was exposed to his father's sounds, he incorporated one of his father's call types into his repertoire. These findings are discussed in light of current theories of sound production mechanisms in odontocetes, developmental stages of vocal acquisition, and vocal learning.