BBC Earth

Facts about sound

Beyond Human
  • Dolphins see their world through sound by using high frequency sounds which humans cannot hear, called ultrasound. Blue whales use infrasonic sound – sounds too low in frequency for our ears to detect.

  • Elephants are one of the few animals on Earth that produce and hear infrasounds, at frequencies less than 20Hz.

  • Humans can hear thunderstorms from 20-30km (12-18 miles) away. But it’s thought that elephants can hear thunderstorms up to 310 miles (500km) away – that’s roughly the equivalent of someone in London listening to a storm in Edinburgh.

  • American alligators produce low frequency sounds in water that causes the droplets on their backs to ‘dance’ at the surface. They use this in courtship rituals to attract females.

  • The golden mole has no eyes and no eternal ears, yet they can hear the faintest of sounds through the sand and can find tiny termites from 20 metres (66 feet) away.

  • Coqui frogs may be just over the size of a two pence piece, but they’re almost as loud as the pneumatic drill. The mating calls of the males have been recorded at up to 95 decibels.

  • Barn owls don’t have external ears. Instead, their facial disc acts as an amazing sound funnel, collecting and filtering sound. Their ears are skewed so one ear is higher than the other – this allows them to capture sounds from above and below, rather than just on a horizontal plane.

  • The older we get, the less able we are to hear high-pitched frequencies. The human range is commonly given as 20-20,000Hz. Flying squirrels produce ultrasonic alarm calls at 50,000Hz, which is way above our hearing range. Tarsiers can produce sounds up to 70,000Hz. Katydids, or bush crickets, can produce sounds of 150,000Hz. Yet the ultrasonic pulses of bats can reach 200,000Hz, creating a visual picture in pitch blackness through sound.