Enter the weird world of a 'worm grunter'

On a misty morning in Florida's Apalachicola National Forest, an eerie sound emanates across the land.

The man creating this bizarre noise, known locally as a "grunt", is Gary Revell, a live bait collector.

I not only love what I do, I’m bonded to it. It’s in my blood to do this

Gary is a hunter with a difference. Armed simply with a wooden stake and a piece of iron, his quarry is unusual: earthworms – and he's possibly one of the best "worm grunters" in the world.

“There’s a technique to it. There’s an art to it. It’s like playing an instrument – either you can play it or you can’t,” explains Revell in the video above, taken from the BBC series World's Weirdest Events.

And play it he sure can. The technique that Revell has perfected is so effective that on a good day Gary says he can catch up to 5,000 worms, which he then sells to fishermen as live bait.

“I not only love what I do, I’m bonded to it. It’s in my blood to do this. I don’t yearn for any other type of employment," he adds.

There are various ways to collect live worms, but Gary hasn't found one that betters his grunts: "There’s no other technique that I know of that can get these worms like this right here; this simple wooden stub and this piece of iron."

Word of the worm grunters' success reached Dr Ken Catania, a professor of Biological Sciences at Vanderbilt University in Nashville, Tennessee, who was intrigued to find out why these worms were being drawn to Gary's bizarre "songs" in such large numbers.

He knows that worms prefer to stay underground, as being on the surface puts them at risk of things such as dehydration and predation. Catania's initial thought was that, rather than being charmed, these worms were fleeing. But from what?

Catania's theory was that the vibrations made by the grunters were mimicking the tunnelling actions of the worms' ultimate subterranean predator: the eastern American mole (Scalopus aquaticus).

Working together with Gary and other worm grunters, Catania discovered that his theory was correct: these live bait collectors were unwittingly mimicking the worms' predator by making vibrations like those of the biggest mole these earthworms had ever sensed.

World's Weirdest Events is currently airing in the UK on Thursdays at 20:00 on BBC Two.