The "skeletons" will say Corpse on them. The thing I've noticed is sometimes you need to "coax" them a bit. The one I "camped" is located in the cave on Tortuga. Sometimes it spawns as a "carrion". Best thing to do is kill the carrion and hope it respawns as a "corpse".
There's another spot on Tortuga in the jungle if you've seen where the big plants are and there's kinda like a farm, near the farm one spawns (think right next to it infact, and if I remember there's an alligator with it). Again though, sometimes you need to kill the skeleton a few times to get the corpse one to spawn. I think that particular one spawns as something other then a carrion when it's not the corpse, forget what off-hand.
Make sure you've some "potions" on you, they enjoy setting fire to your character and other fiendish things.
Stay outa jail!
-SH