The tails of peacocks aren't just pretty to look at. They also make infrasound that humans can't hear
Peacock tails are one of the most beautiful sights in the animal kingdom. But they're not just pretty to look at. The birds also use their huge tails to make a loud noise – which humans are utterly incapable of hearing.
When a peacock shakes his tail, it produces a sound that is so low-pitched, humans can't hear it. That's despite the noise being about as loud as a car going past a few metres away.
Angela Freeman and James Hare of the University of Manitoba in Winnipeg, Canada have shown that peacocks can make these "infrasound" noises with their tails. The birds can also sense and respond to the noise.
"Humans don't often think about infrasound as a potential signal, because we don't perceive it," says Freeman. "I think it's more common than we think."