I went back to vanilla DF after getting my fill of orcs on Dig Deeper, least for now. The map I picked is a mix of evil and normal savage biomes, mountain and badlands. Was watching my dwarves run around inside their encampment, several minutes after the caravans left, when suddenly most of them headed outside. I followed and they were after camel bones and skulls, four camels worth. This puzzled me, as I have all refuse gathering on, and have storage space for corpses by my butcher shop - and the dwarves were not all busy. Corpses have been hauled in before and butchered, so I expect they should have brought the corpses inside, long before they rotted down to bones. And I really would have liked the hides.
When I checked the units list, the only dead camels were four zombie ones. There were five smatterings of blood by the bones.
It's possible that the caravan killed those zombie camels since I didn't watch the caravan leave (and there's no friendly deaths on my unit list), but why didn't my guys go after the corpses before they rotted if so? Would those zombies have rotted to bones that fast? On other maps my dwarves have brought back rotting zombie corpses to decay in my refuse pits. This map has had several 'odd animal deaths' even long before my caravan came, my dwarves running out to get corpses for butchering and when I check the units list and the area the corpses are at I don't see anything to explain what killed those animals, and my dwarves are not being attacked on the way there or back.
No dwarves are set to soldier or hunt, and these corpses are all fairly near the map edges and fairly far from my dwarves' encampment. My civ screen only shows dwarves and there have been no messages about ambushes, so I don't think other races or hidden creatures are killing the beasts and wandering off/hiding again either.
Any ideas?