Giraffes were long believed to be effectively silent because their vocalisations are largely below the frequency humans can hear, but research has shown they produce low‑frequency sounds and use subtle non‑vocal signals for communication.
Anatomy and voicing
Giraffes have a larynx that differs from many other large mammals and their vocal folds produce sounds at very low frequencies with limited acoustic power, which makes most vocal emissions inaudible to humans at typical distances. The combination of long vocal tract and specialised tissue contributes to infrasonic or near‑infrasonic signalling in some contexts.
Infrasound and detection
Field recordings and targeted studies have detected low‑frequency rumbles and other vibrations that giraffes appear to use for close‑range social communication, particularly at night or in dense vegetation where visual cues are less effective; these signals can travel through the ground and air over modest distances.
Alternative communication
Beyond low‑frequency sounds, giraffes rely heavily on visual displays, body posture, neck movements and chemical cues to coordinate social behaviour, warn of predators and maintain group cohesion, making their communication multimodal and often subtle to human observers.
Implications
Recognising giraffes’ use of infrasound and non‑vocal signals reframes our understanding of their social lives and highlights the importance of specialised recording equipment and behavioural observation to reveal communication channels that human senses alone miss.