Using the trunk to feel about under water for a suitable plant, grasping its stems with the trunk to stabilize it, and using a forefoot to "slice" through the stems to separate it from the roots.
A young male is feeding on water lilies. Notice how he feels around under water for a clump, grasps it with his trunk and then uses his foot to slice through it and dislodge it. (Gorongosa, Mozambique)
