@article {58201, title = {Voice breaking and its relation to body mass and testosterone level in the Siberian Crane (Leucogeranus leucogeranus)}, year = {2020}, abstract = {

Vocal development of cranes (Gruidae) has attracted scientific interest due to its special stage, voice breaking. During voice breaking, chicks of different crane species produce calls with two fundamental frequencies that correspond to those in adult low-frequency and juvenile high-frequency vocalizations. However, triggers that affect voice breaking in cranes are mainly unknown. Here we studied the voice breaking in the Siberian Crane (Leucogeranus leucogeranus) and test its relation to the body mass and testosterone level. We analyzed 5846 calls, 39 body mass measurements and 60 blood samples from 11 Siberian Crane chicks in 8 ages from 2.5 to 18 months of life together with 90 body mass measurements and 61 blood samples from 24 Siberian Crane adults. The individual duration of voice breaking and dates of its onset, culmination and completion depended neither on the body mass nor on the testosterone level at various ages. But we found correlation between the testosterone level and mean deltas of percentages of the high and low frequency components in Siberian Crane calls between the closest recording sessions. We also observed some coincidence in time between the mean dates of voice breaking onset and the termination of body mass gain (at 7.5 months of age), and between the mean dates of voice breaking completion and the start of a new breeding season. Similar relations have been shown previously for some other crane species. We also showed for the first time that the mean dates of voice breaking culmination correlated with the significant increase of the testosterone level (at 10.5 months of age). So, we suggest that voice breaking in cranes may be triggered by the end of chicks\’ body growth, is stimulated by the increase of testosterone level and ends soon after adult cranes stop taking care of their chicks.

}, keywords = {Biphonation, Body weight growth, Non-passerine birds, Parent{\textendash}offspring interaction, Sex hormone level in adolescents, vocal development}, doi = {10.1007/s10336-020-01773-w}, url = {http://link.springer.com/10.1007/s10336-020-01773-w}, author = {Klenova, Anna V. and Goncharova, Maria V. and Kashentseva, Tatiana A. and Naidenko, Sergey V.} } @article {57576, title = {Vocal Development of Horsfield{\textquoteright}s Leaf-Nosed Bat Pups (Hipposideros larvatus)}, year = {2019}, abstract = {

Bats are an appealing animal for investigating the biological basis and evolution of speech-related traits in wild mammal systems. We investigated vocal development in Horsfield\&$\#$39;s leaf-nosed bat pups, Hipposideros larvatus. We found that newborn bats emit many types of isolation calls, including downward frequency modulation (DFM), arched frequency modulation (AFM), upward frequency modulation (UFM), and others. The gradual decrease of Euclidean distance measurements revealed that pup isolation calls (DFM, AFM, UFM) gradually change into adult social calls. Furthermore, one of the isolation call types (UFM type) encoded an individual signature. By contrast, we report that early echolocation calls and isolation calls develop in parallel. As pups develop, early echolocation calls gradually mature and transform into adult-like echolocation calls. The interval and duration of echolocation calls decreases, while the peak frequency and bandwidth of frequency modulation increases.

}, keywords = {bats, echolocation calls, individual signature, isolation calls, vocal development}, doi = {10.3161/15081109ACC2019.21.1.016}, author = {Chi, Tingting and LIU, Muxun and Tan, Xiao and Li, Yu and Xiao, Yanhong and Sun, Keping and Jin, Longru and Feng, Jiang} } @article {50502, title = {Age-dependent change in attention paid to vocal exchange rules in Japanese macaques}, journal = {Animal Behaviour}, volume = {129}, year = {2017}, month = {Jan-07-2017}, pages = {81 - 92}, abstract = {

The mechanisms underlying vocal development in nonhuman primates, so-called \‘nonlearners\’, are of special interest because they give an insight in how social factors can shape the expression of an already genetically determined vocal repertoire. Interestingly, recent studies suggest that the acquisition of the complex rules governing vocal exchanges (i.e. context-specific temporal and structural acoustic adjustments) may result from a socially guided development process, with social experience and parental selective feedback playing a key role. Among those conversational rules, call matching is a particularly remarkable phenomenon in Japanese macaques, Macaca fuscata, with interacting adult females matching the frequency range pattern of their own call with another female\&$\#$39;s preceding call. Here, we investigated whether fine-tuned acoustic adjustments during vocal exchanges in Japanese macaques are subject to developmental processes, specifically testing for the ability of individuals of different age classes to discriminate between vocal exchanges respecting, or not, the matching rule. We performed playback experiments in 10 adult and 10 1-year-old captive Japanese macaque females. Each subject was successively exposed to two stimuli: a pair of calls respecting call matching (i.e. two calls from two individuals with matched frequency ranges) and another pair of calls that did not. Adults discriminated better than juveniles whether stimuli respected the call-matching rule or not, and displayed significantly different levels of interest towards each stimulus type. The latency to look towards the loudspeaker was shorter, and the duration of the directed gaze was longer, after the playback that violated the matching expectation in every adult, but not in juveniles which seemingly displayed a random gaze response. Our findings support the conclusion that the matching rule is relevant for adults, but not for socially inexperienced young monkeys which may not have had enough experience of the conversational rules governing vocal exchanges.

}, keywords = {call matching, Japanese Macaque, nonhuman primate, playback experiment, vocal development, vocal exchange}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.05.012}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217301495}, author = {Bouchet, H{\'e}l{\`e}ne and Koda, Hiroki and Lemasson, Alban} }