The noisiest crocodilian is the American alligator Alligator mississipiensis, native to the southwestern USA, including Florida. Its bellowing during courtship, demarcating territory, or when aggravated can be readily heard from a distance of 150 m. At a distance of 5 m, this roaring sound measures approximately 92 decibels, which is almost as loud as standing next to a small propeller aircraft.Scientists believe that this species emits such exceedingly loud bellows because its natural swampy habitat does not readily permit the maintaining of visual communication, so in order to attract mates it has evolved very effective vocal communication instead. Interestingly, it has no vocal cords, producing its ear-splitting bellows by sucking air into its lungs and then forcefully expelling it again.