I don't know either. It seems so inadequate - not even good fly swishing material.
Perhaps, it was last in the line-up when Nature was giving them out and that was all that was left!
So then it ended up with a dewlap or bell, that flap of skin that hangs from the moose's chin, as compensation. The dewlap appears to be larger in bull moose. During the rut, the bull moose rubs the cow with his chin and so it is believed the dewlap transfers the bull's scent to the female.
In any event, even though moose seem to be made up of left over body parts from other mammals, I love their regal and tall stature. (Must remember, though, to carry that shorter lens!)
Moose"THE TALL DARK STRANGER"