The giraffe, the tallest land animal, has long been mistakenly characterized as nearly silent. This widespread misconception led many to believe that these magnificent animals lack the ability to vocalize altogether. However, modern research has definitively shown that giraffes do make a variety of noises, ranging from sudden, short bursts of air to sustained, low-frequency tones. The infrequency and nature of their sounds explain the long-standing mystery surrounding their vocal habits.
Why Giraffes Are Considered Silent
The belief that giraffes are silent creatures stems largely from a combination of their unique physical anatomy and their social behavior. The most obvious physical factor is the giraffe’s extremely long trachea. This elongated windpipe presents a significant physiological challenge, as air must be pushed a great distance to generate enough pressure to vibrate the vocal cords in the larynx effectively.
This anatomical constraint means that generating loud, high-frequency sounds is difficult, favoring the production of lower-frequency vocalizations that are often less noticeable to the human ear. Furthermore, giraffes are not territorial, and their social groups are typically loose. They rely heavily on their excellent eyesight and height for visual communication across the open savanna, making frequent audible calls unnecessary.
A Catalog of Daytime Vocalizations
While infrequent, giraffes produce several distinct, sudden sounds during the day related to alarm, distress, or specific social interactions. One of the most commonly observed sounds is the snort, a sharp, forceful expulsion of air through the nostrils, often serving as an alarm signal to other herd members when a potential threat is detected. Hisses are also noted in defensive situations, produced by a forced exhalation that accompanies aggressive body language, such as leg stomping.
Other sudden sounds include grunts and coughs, which are short, guttural noises associated with discomfort or sudden movements. Calves are more vocal than adults, producing bleating or mewing noises when separated from their mothers or in distress. Adult giraffes have also been documented producing deeper bellows or moans during severe circumstances, such as injury or male courtship rituals.
The Discovery of Nighttime Humming
The most sustained and complex vocalization discovered came from a 2015 study that analyzed audio from giraffes in European zoos, revealing a distinct, low-frequency humming sound. This humming is a harmonic, sustained, and frequency-modulated vocalization that occurs almost exclusively during the nocturnal hours. The recorded hums are within the audible range for humans, averaging approximately 92 Hertz.
Researchers recorded this unique sound, indicating that even this sustained vocalization is a relatively rare event. The function of the nighttime hum is still under investigation, but the prevailing theory suggests it serves as a contact call, helping individuals maintain cohesion when visual contact is not possible.