In the 2000s or 2010s, I read a review about a sci-fi novel in which we learned that dolphins could not only navigate by echolocation, but communicate by it.
In other words, a dolphin could "squeak" in such a way that would appear, to another dolphin's sonar sense, the same as a rock or other solid object.
The author, if I recall correctly, referred to this as telepathy, because one dolphin could transmit "images" to another. Technically, however, it's transmitting sonograms.