Biologists from Tel Aviv University have found that plants emit sounds comparable in volume to normal human conversation when they are stressed. With frequencies of 20-100kHz, these sounds are too high-pitched for humans to hear, but it is likely they can be heard by insects and perhaps by other mammals, the researchers say.
“Even in a quiet field, there are actually sounds that we don’t hear, and those sounds carry information,” said senior author Prof Lilach Hadany, an evolutionary biologist based at Tel Aviv University.