Today tonight or explanation of rynchokinesis addendum

["Philip Veerman" <>]

Oh I should add this rynchokinesis is easily seen in finches and parrots as they manipulate and crush seeds. Anatomically it is exactly the same muscles and bones doing this as shown in these waders. The difference being that in finches and parrots the upper mandible is hard and the hinged part is at the base of the upper mandible. So as we see it, the whole upper mandible moves up and down. In these waders, the soft part (the keratin of the beak cover) is far along the very long thin beak and the bones that rock back and forth as the quadrate is moved back and forth are much longer. In effect the hinge has been moved forward during the evolution of this family of birds. In us mammals, the upper mandible is fused as a main part of the skull and we don't have a quadrate bone to slide the lower mandible.

 

Philip