An exaggerated form of Periscope-Trunk in which lead individuals in a family use a dramatic, highly visible, repeated sweeping movement of the entire trunk, down, outstretched, up, outstretched and down, which serves to galvanise members of their group into a Coalition to confront a threat. Trunk-Sweep is associated with Purposeful-Walking, often of the form Perpendicular-Walk. Our observations suggest that this behavior is a purposeful signal to others, a call to action. This behavior is prominently observed among lead females in a family and occurs during Coalition Building and Mobbing & Attacking contexts.
The Mabenzi family is Bunching as they walk in a Group-March. They are on their way to water and were caught out the open and are concerned. Note that at the same moment that Mwana Nzo, gf0016, Orients-Toward us and lifts her trunk in a Trunk-Sweep movement (behind Valente), Valente,gf0013, too, Orients-Toward us, and others follow her lead in synchrony as they all face us.
Valente searches for Mwana Nzo reaching her trunk out towards her in what appears to be an attempted Reach-Touch - as if in solidarity. Then Mwana Nzo come to the fore and the main females lead entire group toward the camera in a broad front in solidarity. Then as Mwana-Nzo does another Trunk-Sweep movement all turn again and Mwana Nzo takes on Rear-Guard. Then a last Trunk-Sweep - most of the group is out of sight but one young female turns to watch and follows her lead. (Gorongosa, Mozambique)
