This accomplished gourd shaped rattle is actually made from a hardwood. There is a plug on the side which is where the inside has been hollowed out and filled with small hard objects (seeds?) to make it a rattle. As gourds were widely used by all classes as vessels, implements and utilatarion items the fact that the shape of a gourd was skillfully copied in wood suggests it was a prestige item used by a wealthy and important person.
Reference: See a similar wooden "bottle" published in _African Furniture and Household Objects_, pp. 190. The caption reads: "This bottle is a close copy of a decorated calabash."