Highs and Lows

Everyone knows bats use ultrasound (high frequencies) to echolocate and, in some cases, catch night-flying insect prey. Recent studies, however, show they also use low frequencies to communicate with eachother (https://www.theguardian.com/science/2022/nov/29/bats-are-the-death-metal-singers-of-the-animal-world-research-shows). Bats have thick structures in their larynx (windpipe) called ventricular folds. These are used to produce low frequency calls, said to be similar to those employed by death metal pop artists and Tuvan (Mongolian) throat singers.