A group of researchers was able to discover that contrary to what most experts and people believe, giraffes make sounds; and in a new study, the scientists were even able to figure out what kind of sound these long-necked animals make.
According to previous studies, giraffes (Giraffa camelopardalis sp.) present a system that exude fission, fusion and social structure. Species having this type of living rely on vocal communication heavily as exchange of information is highly critical for them. With this, the said animals devise strategies to interact with each other in their own ways.
Although giraffes are known to make sounds, it is not clearly established whether they use vocal means to exchange data or not. In the past, researches that delved into the vocal properties of giraffes were considered anecdotal and the lack of acoustic definitions hindered the experts to identify a call vocabulary. With this, giraffes have been theorized to make infrasonic vocalizations just like elephants, despite missing evidence-based data.
The researchers of the new study wanted to come up with a comprehensive investigation regarding the vocal interaction among giraffes using information from captive species during the day and night. The experts narrowed their assessments on the infrasonic, tonal or sustained vocalizations.
The scientists from the University of Vienna and Berlin Tierpark in Germany collated eight-year worth of data, consisting more than 947 hours of audio data from three zoos in Europe. They then measured the temporal and spectral properties of the acoustic signs to come up with a precise set of acoustic indicators.
The findings of the study, published in the BioMed Central, showed that aside from the common sounds of grunting, snorting and bursting, the giraffes were noted to exhibit sustained, harmonic and frequency-modulated sounds, comparable to humming sounds during the night time.
"These results show that giraffes do produce vocalizations," said the researchers. If these results will be studied alongside the animals' acoustic structure, it is possible that these sounds are being used as a communication tool between the species.
In the past, park rangers and scientists thought that the long necks of giraffes hindered them to have adequate airflow in its trachea that measures about four meters long. Because of this, the giraffes were hypothesized to lack the ability to vibrate their vocal folds and generate sounds. But in this new research, which involved quantifying the association between vocal folds and noise production, the experts found that the humming sounds came where it was supposed to be and that giraffe humming was stronger than expected.
Photo: Martin Pettitt | Flickr
