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In female terrestrial mammals, vocal aging has only been studied in humans and pandas. In cervids displaying convergent sex dimorphism of vocal apparatus with humans, vocal aging is only investigated in males. This cross-sectional...
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In female terrestrial mammals, vocal aging has only been studied in humans and pandas. In cervids displaying convergent sex dimorphism of vocal apparatus with humans, vocal aging is only investigated in males. This cross-sectional study examined acoustic variables of nasal (closed-mouth) and oral (open-mouth) contact calls of 32 farmed Iberian red deer hinds (Cervus elaphus hispanicus) aged of 4-18 years and their relationships with caller's age, weight, social discomfort score (bites of other hinds on hind pelt) and body condition score (fat reserves). Decrease of fundamental frequency was associated with age in both oral and nasal calls, but more prominently in the nasal calls. An increase in call duration, peak frequency and power quartiles was associated with a higher degree of bites due to social aggression. Weight and body condition weakly influenced acoustic traits. We discuss that vocal aging of hinds parallels that of vocal aging in human females.
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In species in which males and females exhibit different association patterns, the use of vocalizations that regulate interindividual distance may differ between the sexes. Spider monkey social groups are characterized by high fiss...
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In species in which males and females exhibit different association patterns, the use of vocalizations that regulate interindividual distance may differ between the sexes. Spider monkey social groups are characterized by high fission-fusion dynamics and sex differences in association patterns; female-female associations have been described as more passive than those between philopatric males. Individuals of both sexes produce whinny vocalizations, which may allow callers and receivers to mediate interindividual spacing based on existing social relationships. As such, we hypothesized individuals of each sex would use whinny vocalizations at different rates and in different contexts. To investigate sex differences in the rate of whinnying across behavioral contexts, we collected focal animal samples on Yucatan spider monkeys (Ateles geoffroyi yucatanensis) over 8 mo at Runaway Creek Nature Reserve, Belize. In addition, we recorded all changes in subgroup composition to investigate whether a female's likelihood of calling was influenced by the number of conspecifics joining, or leaving their subgroup. We found that females called at higher rates than males in most behavioral contexts, especially foraging. The probability that females would call increased during subgroup fissions and fusions, and correlated positively with the number of individuals joining or leaving their subgroup. Male calling rates did not differ across contexts, and males generally called less than females. Our results suggest that whinnying by females may allow callers to mediate interindividual spacing in contexts where proximity risks increasing feeding competition. In species in which the sexes associate in qualitatively different ways, vocalizations may play a role in maintaining these differences.
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In the domesticated common canary (Serinus canaria) a particular phrase called phrase A elicits a high level of sexual responses in females. We know that during male/female or male/male encounters, emitters produce longer phrases ...
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In the domesticated common canary (Serinus canaria) a particular phrase called phrase A elicits a high level of sexual responses in females. We know that during male/female or male/male encounters, emitters produce longer phrases A. The aim of this study was to test song influences on adult male canaries and especially the influence of phrases A. We used two sets of conspecific songs (the first set containing phrase A, the second set lacking phrase A), and one set of heterospecific songs (control set). Responses of eighteen males were measured using calls rate. We observed that numbers of calls emitted during silence are similar, regardless to the songs we played back. Conversely, we observed that calls rate is significantly lower during playbacks of phrases A than during the two other types of song playbacks. This suggests that males may discriminate among songs, especially between phrases A and other types of conspecific phrases.
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A major function of contact calls in nonhuman primates is to maintain spatial cohesion among individuals in a group. The risks of spatial/visual separation from the group are likely to affect auditory contact behavior, in particul...
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A major function of contact calls in nonhuman primates is to maintain spatial cohesion among individuals in a group. The risks of spatial/visual separation from the group are likely to affect auditory contact behavior, in particular by increasing the call rate. We tested whether the risk of separation influences coo call emission by investigating the variation in call rate among behavioral contexts in two wild populations of Japanese macaques (Macaca fuscata). We focused on caller activity and the degree of visibility within the habitat as primary potential factors mediating call rate. We first estimated the habitat visibility of the two research sites at Yakushima Island (YK) and Kinkazan Island (KZ), Japan. The habitat visibility of YK was significantly more restricted than that of KZ. We then compared the call rate of 20 adult and 12 juvenile female macaques between the two wild populations to examine the potential effects of environmental differences. Both populations had a lower call rate during grooming than during feeding and moving, which are behaviors associated to higher interindividual distances. The call rate of YK adult females was significantly greater than that of both juveniles and KZ adult females, independently of activity. The call rate increased as macaques matured in the YK population, but not in the KZ population, suggesting that different developmental processes involved in contact calling of the two populations. Our findings suggest that separation risk influences call rate, and also imply a possibility of social influence that social structure change effects on the call rates. Am. J. Primatol. 70:1055-1063, 2008. (c) 2008 Wiley-Liss, Inc.
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Eurasian deer are characterized by the extraordinary diversity of their vocal repertoires. Male sexual calls range from roars with relatively low fundamental frequency (hereafter fo) in red deer Cervus elaphus, to moans with extre...
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Eurasian deer are characterized by the extraordinary diversity of their vocal repertoires. Male sexual calls range from roars with relatively low fundamental frequency (hereafter fo) in red deer Cervus elaphus, to moans with extremely high fo in sika deer Cervus nippon, and almost infrasonic groans with exceptionally low fo in fallow deer Dama dama. Moreover, while both red and fallow males are capable of lowering their formant frequencies during their calls, sika males appear to lack this ability. Female contact calls are also characterized by relatively less pronounced, yet strong interspecific differences. The aim of this study is to examine the anatomical bases of these inter-specific and inter-sexual differences by identifying if the acoustic variation is reflected in corresponding anatomical variation. To do this, we investigated the vocal anatomy of male and female specimens of each of these three species. Across species and sexes, we find that the observed acoustic variability is indeed related to expected corresponding anatomical differences, based on the source-filter theory of vocal production. At the source level, low fo is associated with larger vocal folds, whereas high fo is associated with smaller vocal folds: sika deer have the smallest vocal folds and male fallow deer the largest. Red and sika deer vocal folds do not appear to be sexually dimorphic, while fallow deer exhibit strong sexual dimorphism (after correcting for body size differences). At the filter level, the variability in formants is related to the configuration of the vocal tract: in fallow and red deer, both sexes have evolved a permanently descended larynx (with a resting position of the larynx much lower in males than in females). Both sexes also have the potential for momentary, call-synchronous vocal tract elongation, again more pronounced in males than in females. In contrast, the resting position of the larynx is high in both sexes of sika deer and the potential for further active vocal tract elongation is virtually absent in both sexes. Anatomical evidence suggests an evolutionary reversal in larynx position within sika deer, that is, a secondary larynx ascent. Together, our observations confirm that the observed diversity of vocal behaviour in polygynous deer is supported by strong anatomical differences, highlighting the importance of anatomical specializations in shaping mammalian vocal repertoires. Sexual selection is discussed as a potential evolutionary driver of the observed vocal diversity and sexual dimorphisms. ? 2021 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.
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Parrots have enormous vocal imitation capacities and produce individually unique vocal signatures. Like songbirds, parrots have a nucleated neural song system with distinct anterior (AFP) and posterior forebrain pathways (PFP). To...
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Parrots have enormous vocal imitation capacities and produce individually unique vocal signatures. Like songbirds, parrots have a nucleated neural song system with distinct anterior (AFP) and posterior forebrain pathways (PFP). To test if song systems of parrots and songbirds, which diverged over 50 million years ago, have a similar functional organization, we first established a neuroscience-compatible call-and-response behavioral paradigm to elicit learned contact calls in budgerigars (Melopsittacus undulatus). Using variational autoencoder-based machine learning methods, we show that contact calls within affiliated groups converge but that individuals maintain unique acoustic features, or vocal signatures, even after call convergence. Next, we transiently inactivated the outputs of AFP to test if learned vocalizations can be produced by the PFP alone. As in songbirds, AFP inactivation had an immediate effect on vocalizations, consistent with a premotor role. But in contrast to songbirds, where the isolated PFP is sufficient to produce stereotyped and acoustically normal vocalizations, isolation of the budgerigar PFP caused a degradation of call acoustic structure, stereotypy, and individual uniqueness. Thus, the contribution of AFP and the capacity of isolated PFP to produce learned vocalizations have diverged substantially between songbirds and parrots, likely driven by their distinct behavioral ecology and neural connectivity.
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In their natural West African rainforest habitat, Diana monkeys continuously produce high rates of a close-range clear-sounding call, but the function of this behaviour is unknown. In other primate species, close-range calls are t...
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In their natural West African rainforest habitat, Diana monkeys continuously produce high rates of a close-range clear-sounding call, but the function of this behaviour is unknown. In other primate species, close-range calls are typically given in socially relevant situations, for example, to gain access to grooming partners or food. Quite contrarily, we tested a number of hypotheses and found that Diana monkey 'clear' calls primarily function to avoid predation. Call rates were significantly elevated when predation threat was high, for instance when the visibility was poor, when the group spread was large, when the group was not associated with other monkey species. or after alarm calls. Call rates were not significantly elevated, however, in circumstances of high social competition, for instance when the group spread was small, during resting phases, while feeding oil clumped food sources, or when foraging in the periphery where inter-group encounters were more likely to occur. Calling was contagious in that calls typically elicited vocal responses from out-of-sight group members within a few seconds. Because of this, callers can effectively monitor a much larger area than is visually accessible to single individuals, suggesting that Diana monkey clear calls act as an essential element in a mutualistic system of co-ordinated vigilance.
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Learned vocalizations play a key role in parrot social dynamics and vocal dialects have been documented for several mainland species, but to date no studies of geographically structured call variation in parrot species have examin...
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Learned vocalizations play a key role in parrot social dynamics and vocal dialects have been documented for several mainland species, but to date no studies of geographically structured call variation in parrot species have examined the role of isolation on islands. In a study of the Brown-throated Parakeet (Eupsittula pertinax), which inhabits 5 small Caribbean islands as well as the adjacent mainland, we found that the contact calls of island and mainland parakeets show divergence in vocal characters as well as in call variability. We assessed call variation using 3 approaches: frequency measurements, spectrogram cross-correlation (SPCC) analyses, and call duration measurements. Island parakeets' calls were longer and had lower mean frequencies, and calls from different islands were distinguishable from each other as well as from mainland calls using measures derived from the SPCCs. In addition, we measured call variability at 2 different levels-within-location and within-individual. We found calls to be more variable for island parakeets for SPCC and duration measures, but less variable for frequency measures. The observed call differentiation among locations may be due to drift, whereas the lower frequency of island calls could either be a response to the windy environment on the islands or a consequence of the island subspecies' larger body sizes. We also hypothesize that the isolation of parakeet populations on small islands may have resulted in reduced selection for local call convergence, allowing island parakeets to produce more variable calls. We suggest that due to poor signal transmission in the windy island environment, selective pressures may favor variability in more easily perceived call features (like call duration) rather than more subtle features, like frequency shifts. Experimental tests are required to determine whether observed call patterns translate into similarly structured patterns in the responses to vocal variants.
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