Yes they do, and with a balanced underground contact microphone you can pick up lots. Though ideally you want large soil sample box with target animal (ants or

Yes they do, and with a balanced underground contact microphone you can pick up lots. Though ideally you want large soil sample box with target animal (ants or worms) and that inside an acoustic chamber to rule out external noise. It's amazing how much sound there is out there, hard thing is filtering out the rest and capturing those low dB sounds that are often drowned out. Now with an array of microphones you could potentially track the movements of the target underground animal, but be some serious effort. Basic balanced contact micrphone how to build https://www.instructables.com/Balanced-piezo-contact-microphones/ https://www.instructables.com/Balanced-piezo-contact-microph... Suggest adding sandwich layer that's non conductive but also good at picking up sound in the frequency range you are targeting - small shard of glass works nice, but again, it's a whole rabbit hole of exploration you may or may not wish to go down. I can also recommend the behringer 202hd as a good preamp on a budget for such a balance contact microphone. Or for something non balanced https://jezrileyfrench.co.uk/contact-microphones.php https://jezrileyfrench.co.uk/contact-microphones.php do top microphones and that model was used for many BBC Nature documentaries with David Attenborough. Though personally not used those myself.