How about feeding worms a radioactive tracing agent to follow their trails?
Also, PSA from my high-school biology teacher that has been living rent-free in my head so far: If you intend to eat earthworms, letting them feed on coffee grounds helps clean their intestines so you don't get sand in your teeth.
Also, PSA from my high-school biology teacher that has been living rent-free in my head so far: If you intend to eat earthworms, letting them feed on coffee grounds helps clean their intestines so you don't get sand in your teeth.