Elephants don't need cell phones to hold long distance conversations, their deep calls can travel miles. And although humans can't always hear these vocalizations because of their low frequency, elephants produce them using the same mechanism that lets humans speak and sing. That finding is in the journal Science. Until now, scientists did not know whether the elephant made sound the way we speak or differently, such as the way cats purr. A human produces noises because the vocal cords vibrate automatically when air flows past. But a cat must actively squeeze the muscles of its larynx to produce its deep, rhythmic purr. When a zoo elephant died of natural causes, researchers took the animal's larynx to their lab and ran air through it to find out which method elephants use to make sound. They could reproduce the large mammal's low-frequency rumble, which means that an elephant doesn't need to actively control its larynx like a cat does. For those who contend that this is irrelevant, "Irrelevant. There's a whole lot of irrelevant's in the circus."