A question regarding the twelve ayatanas: I get that there are the eye, ear, nose, tongue, body and mind; as well as their corresponding objects of visible form, sound, smell, taste, touch and mental objects. But what about senses that don't clearly fall into any of these categories, such as equilibrioception?
The sense of equilibrioception seems to depend largely on the ear, but I don't think it could be regarded as a sound object. But it also seems to depend on sight and brain functioning, but it doesn't seem to be clearly a visible ayatana or a purely mental object, either.
And how about the radar perception of a being such as a bat? These animals appear to create an entire visual-like impression based on interpretation of touch objects and sound. Or bees, which seem to communicate with pheromones (people perceive pheromones too), but it hardly seems like a purely smell object. In these cases, the distinction between "touch" and "sound" and "visible form" seems to become blurred.
And I can imagine the possibility of a being who has sense perceptions with which human beings are not familiar. I'm wondering, would all such senses be understood as having their base solely in the 12 ayatanas? And if that is so, could there be more to the ayatanas than what we, in our human form, are able to perceive and understand?