Diorama at Anchorage IAP depicting Native Alaskan hunting Belugas on the upper Cook Inlet

What is the mannequin supposed to be standing on? A tree growing out of the water?

The upper Cook Inlet is shallow and it’s bed made up of mud and glacial silt. The tidal actions in the upper reaches, where waterway narrows, will cut channels through the mud. Outflow from rivers also does this. These channels are used by Salmon as they return up river to spawn and by the Belugas who hunt them. The Dena’ina people made stands from uprooted trees fixed into the mud flats, along these channels, at the mouths of the rivers, to ambush the Beluga. I am sure they also hunted from boats, but this method put them in the exact right place…aided by their knowledge of the cycles of Salmon and Tides…to harvest the whales.

Note that in designing the diorama the creators took care to show how the movement of the water enabled this activity and shaped the environment in which Humans, Beluga, and Salmon interacted with each other.