If you're heroically bored or crazy or both, you can farm 9,999 of these bones to trade in for a shiny Bone-White Primal Raptor mount. As added torture, these bones only drop for one person in your party at a time, although you may need a group to kill the mobs. The turn in is A Mountain of Giant Dinosaur Bones and will award the achievement I've Got 9999 Problems but a Bone-White Primal Raptor Ain't One. If you're not bored or crazy, you can admire the bored and crazy people's sweet dinosaur mount from afar.
There are other lesser rewards you can earn with smaller quantities of bones. Here is the full list of things you can "buy" with these bones.