This is, I think, a section from a two-piece primitive wooden chair.  Hand carved from an unknown wood.  It seems to be African, but I can't say for sure.  I believe this is the seat section, rather than the back.  The narrow part would fit through a slot and form the back "leg" of the chair.

The carvings may represent lizards or frogs.   The other side is blank.

It could also be used as a wall plaque, and has a metal hanger on the back for that purpose. 

Length:  30"
Width (at the widest point):  15 1/5"