Hiss and snort call types of wild-living giraffes Giraffa camelopardalis: acoustic structure and context

Abstract

ObjectivesVocalization as part of vigilance behaviour is widespread across animal taxa, including ruminants. Calls of wild-living giraffes have never been recorded and spectrographically investigated. This study reports the acoustic structure of vigilance-related hiss and snort calls of wild-living giraffes Giraffa camelopardalis.ResultsThe hiss and snort calls were emitted during five recording sessions produced by nine individual giraffes (8 adults and 1 subadult) in their natural environment in Namibia (3 individuals) and Kenya (6 individuals). These calls attended vigilance behaviour toward humans in hides or in vehicles and cheetahs as natural predators of giraffe young. This study provides spectrographic analyses of 22 hiss and 20 snort calls. The giraffe hisses were broadband vocalizations of an average duration of 0.72 s (from 0.24 to 1.04 s) and a peak frequency of 0.69 kHz. The giraffe snorts were broadband pulsed calls of an average duration of 0.28 s (from 0.13 to 0.55 s), a peak frequency at 0.20 kHz and comprised a prominent low-frequency pulsation of 23.7 pulses/s. The acoustic structure of giraffe hisses is reminiscent of vigilance-related hisses of musk deer Moschus moschiferus. Giraffe snorts differ from snorts of other ruminants by their prominent pulsed pattern.Electronic supplementary materialThe online version of this article (10.1186/s13104-017-3103-x) contains supplementary material, which is available to authorized users.

How do giraffes locate one another? A review of visual, auditory, and olfactory communication among giraffes

“…We found ten studies that referenced giraffe vocal communication (Table ). Among these, five recorded and spectrographically examined giraffe vocal signals (Bashaw, ; Hurgitsch, ; Von Muggenthaler, ; Baotic et al ., ; Volodina et al ., ; Table ). The vocal signals described across these studies are categorized as snorts, hisses, hums, bursts, and growls.…”

“…Volodina et al . () provide the most recent and only spectrographic descriptions of vocalizations from wild giraffes. These vocalizations were categorized as hisses and snort calls with peak frequencies 0.69 ± 0.61 kHz and 0.20 ± 0.29 kHz respectively (Table ).…”

“…Early studies deemed giraffes to be mute, and the inability to produce sounds correlated with giraffe's inability to produce an air flow of sufficient velocity to vibrate the thyro‐arytenoid folds or arytenoids (Harrison, ). That belief has since been disproved as several studies have made recordings of hisses, snorts, low‐humming vocalizations, and infrasonic signals in giraffes (Bashaw, ; Von Muggenthaler, ; Baotic et al ., ; Volodina et al ., ; Table ). These studies provide the only known spectrographic descriptions of giraffe vocal signals.…”

“…It should also be mentioned that four of the current studies on vocalization have been conducted exclusively on captive giraffes. Obtaining giraffe vocal signals is intricate and time consuming (Baotic et al ., ; Volodina et al ., ). For instance, Volodina et al .…”

“…Communication is one of the aspects of giraffe ( Giraffa camelopardalis ) behavior and ecology that has intrigued biologists, ecologists, and society for many years (Innis, ; Berry, ; Dagg & Foster, ; Bashaw, ; Von Muggenthaler, ; Baotic, Sicks & Stoeger, ; Volodina et al ., ). Despite this fascination, communication remains one of the most understudied aspects of giraffe ecology.…”