Giraffes are known to be quiet animals, and for a long time, it was believed that their necks were too long for them to produce sounds by propelling air from their lungs across their vocal cords and out of their mouths. However, recent research suggests that giraffes do make sounds, and they hum at a frequency of 92Hz, which is still audible to humans but pretty low. The humming is a low-frequency vocalization thats quiet, yet still within the range of human hearing. Biologists say that all giraffes have vocal cords and make sound, and the humming noise they make might have the potential to function as communicative signals to convey information about the physical and motivational attributes of the caller. Therefore, the sound that a giraffe makes is a low humming noise.