Creating Exosomatic Signals

Some lorikeets rearrange the food containers when they become empty, by putting one or two empty containers on top of another. The rearrangement thus signals the current lack of food until they are put back into the original configuration, which then signals the reappearance of food. The fact that this is done by different individuals suggests that it functions as a social semiotic. This goes well beyond the limits of protolanguage.