Earthworms eating

On the all-animals-eating collection, this strange recording is about earthworms. These are earthworms eating. There's normally no noise or quite nothing with earthworm, but I was completely atracted to disclose their secret life. So, to succeed, I made a strategy. I buried two adjoined contact microphones in a very packed mold. Around the microphones, I disposed a layer of coffee ground, as I know earthworm love wet and cold coffee ground. It was a trap and a gift to them, in aim to attract them near the microphones. I deposited three nervous earthworm on the summit of a jam jar. I let them dig in the mold. They immediatly plunged near the coffee and eat it. It makes this extremely strange sound. On this recording, I made no alteration, but in fact I really can't explain why it makes these kind of noises. Perhaps ground small collapses and crushing is a kind of important thing in a earthworm existence.