Unlike most moths, which generate noise by rubbing external body parts together, all three species within the genus Acherontia are capable of producing a "squeak" from the pharynx, a response triggered by external agitation.

The moth sucks in air, causing an internal flap between the mouth and throat to vibrate at a rapid speed. The "squeak" described is produced upon the exhalation when the flap is open. Each cycle of inhalation and exhalation takes approximately one fifth of a second