African elephants can be found roaming the forests and grasslands of 37 countries across the continent. But sadly, these sentient and intelligent animals are rapidly declining, and were recently declared endangered. For these remaining elephants to find each other, they make a variety of vocal noises to greet and warn each other, or to woo potential mates. Some of their vocalizations, which are called rumbles, are very low-pitched. So low in fact that humans can barely hear them.
