It is even possible that certain echolocated objects may be perceived a little on the inside, given their relative transparency to sound. There is evidence that a dolphin "sees" the last thing a herdmate ate, because it detects its visceral hollows and measures their degree of repletion. Otherwise, it almost certainly notices clearly that the diver filming it has a platinum thigh prosthesis (metal returns much more of an echo than bone, it is "shinier").
·