Crickets chirp to attract mates and warn off the competition, and crickets 165 million years ago chirped (technically, “stridulated”) for the same reasons. But Jurassic-age crickets, Archaboilus musicus, were Jurassic shaped, with different forewings—which crickets rub together to produce their familiar sound—and therefore produced an altogether different song.
Scientists recently found an extremely well-preserved example of A. musicus’ “stridulatory apparatus in the forewings” and extrapolated the sound based on current species of crickets. Then they uploaded the results to YouTube for our listening pleasure.
According to an abstract in the Proceedings of the National Academy of Sciences,
…the low-frequency musical song of A. musicus was well-adapted to communication in the lightly cluttered environment of the mid-Jurassic forest produced by coniferous trees and giant ferns, suggesting that reptilian, amphibian, and mammalian insectivores could have also heard A. musicus‘ song.
Now 21st century mammals get to hear it. Whether or not you’re an insectivore is entirely a matter of taste.