Go to the far end of this little ledge and turn left. You can then 'zoom' on this large plant and you will be sitting in it. If you rotate around you will note that the plant mimics sounds from the world, depending on where it is pointed. Point it down towards where the little animal was eating the nectar of the plant and it will mimic that sound, opening up the plants behind you. You can then go up the ladder and walk across the top to the door of the tusk.
Frustrating, huh?