Nocturnal “humming” vocalizations: adding a piece to the puzzle of giraffe vocal communication

BMC Research Notes

Angela S. Stoeger¹  Florian Sicks²  Anton Baotic¹ 

[1] Department of Cognitive Biology, University of Vienna, Althanstr. 14, Vienna, 1090, Austria;Berlin Tierpark, Am Tierpark 125, Berlin, 10319, Germany

关键词: Communication;    Acoustic;    Call;    Vocalization;    Hum;    Giraffe;    Giraffa camelopardalis;   

Others  :  1230258
DOI  :  10.1186/s13104-015-1394-3

 received in 2015-05-15, accepted in 2015-08-28,  发布年份 2015

【 摘 要 】

Background

Recent research reveals that giraffes (Giraffa camelopardalis sp.) exhibit a socially structured, fission–fusion system. In other species possessing this kind of society, information exchange is important and vocal communication is usually well developed. But is this true for giraffes? Giraffes are known to produce sounds, but there is no evidence that they use vocalizations for communication. Reports on giraffe vocalizations are mainly anecdotal and the missing acoustic descriptions make it difficult to establish a call nomenclature. Despite inconclusive evidence to date, it is widely assumed that giraffes produce infrasonic vocalizations similar to elephants. In order to initiate a more detailed investigation of the vocal communication in giraffes, we collected data of captive individuals during day and night. We particularly focussed on detecting tonal, infrasonic or sustained vocalizations.

Findings

We collected over 947 h of audio material in three European zoos and quantified the spectral and temporal components of acoustic signals to obtain an accurate set of acoustic parameters. Besides the known burst, snorts and grunts, we detected harmonic, sustained and frequency-modulated “humming” vocalizations during night recordings. None of the recorded vocalizations were within the infrasonic range.

Conclusions

These results show that giraffes do produce vocalizations, which, based on their acoustic structure, might have the potential to function as communicative signals to convey information about the physical and motivational attributes of the caller. The data further reveal that the assumption of infrasonic communication in giraffes needs to be considered with caution and requires further investigations in future studies.

【 授权许可】

   
2015 Baotic et al.

【 图 表 】

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