The nearly-infrasonic call of the not-so-friendly cassowary (picture a ‘flamboyant ostrich’ with 5-inch daggers for claws). One of the largest birds on Earth, the cassowary lives a secretive life, preferring to lurk out of view in dense South Pacific vegetation. But other creatures feel their presence in the form of that throbbing call that hits tones as low as 23 Hz. In that range, human hearing begins to trail off into uncertainty. Directional perception breaks down and ‘ubiquity effects’ (‘it’s coming from everywhere’) begin to bloom. This adds an unsettling sonic layer to daily life in the rainforest: bodies hummed, nerves put on edge, by a volatile neighbour that seems to be everywhere and nowhere.
via Wild Ambience