A giraffe makes a lot of different noises, even though it is rare to hear one make any sound at all. A giraffe makes a snorting sound as a warning when alarmed or when sensing danger. A giraffe can produce mooing sounds, grunts, hisses and even a roar.
A giraffe has lungs that can hold up to 12 gallons of air, and its heart can weigh as much as 25 pounds. A giraffe can moo like a cow or make a grunting sound like a pig. Some of the sounds that a giraffe makes may be in tones that the human ear is unable to hear.