Here's a very in depth article on the awful trade in Rhino Horn from the Yemen Observer - Conservationists keep rhinos from becoming jambiyas.

No rhinoceros roams the wilds of Yemen, yet this country and that animal are intimately entwined, in a relationship that has put the rhino at great risk of extinction. The connection between Yemen and the dwindling herds of rhinoceros can be found hanging from the belts of Yemeni men.