Field note. The dwelling is fitted with a summoning device: a small illuminated stud beside the primary aperture, positioned at the height of a standing adult's hand.
The mechanism is elegant. An arriving organism presses the stud. Inside, a two-note oscillation propagates through the structure. The interior organisms, upon receiving this vibration, undergo an immediate coordinated seizure. One rises abruptly from rest. Others fall silent mid-vocalization. A quadruped specimen, previously inert, converts entirely to sound and velocity, hurling itself at the aperture in what I first classified as a defense response but now believe to be ecstatic malfunction.
I have documented the sequence forty-one times. The interior organism approaches the aperture. It pauses. It applies one eye to a small ground-glass lens set in the barrier, confirming the identity of the summoner it has already, by scent and schedule, deduced. Then it performs the most revealing act. Before opening, it rearranges its own face.
It adjusts the musculature around the mouth into an upward configuration, straightens its posture, and modulates its vocal pitch higher. It does this while no one can yet see it.
This is the datum I cannot resolve. The summoned organism prepares an expression for an observer who does not yet exist, then delivers that expression the instant the barrier parts, as though it had been experiencing it all along.
Correction to earlier hypothesis: the device does not summon the resident. It notifies the resident that it has approximately four seconds to become a different, warmer version of itself before witnesses arrive.
Conclusion: the stud is not a doorbell.
It is a warning system, and the thing it warns against is being caught unprepared to perform affection.