Finding Ancient Bone in Palworld is rather tricky if you haven't clocked that each of the three ancient materials come from the wildlife sanctuaries dotted around the islands. These areas are easy to recognise because of the big shield domes protecting them, but that does mean you have to sneak about and avoid their protectors while doing your illicit mining.
Only one of these sanctuaries contains Ancient Bone, though, so you'll have to head there if you want to craft the fancy accessories that require it.
Palworld Ancient Bone location
You can find Ancient Bone in the No.3 Wildlife Sanctuary northeast of the Dessicated Desert, which is itself in the northeast of the game's starting islands. It's easy to spot, since, like other wildlife sanctuaries, it has a big blue dome shield you can spy at a distance. You'll want to head to the Deep Sand Dunes fast travel in the north of the desert (bring heat resistance for day and cold resistance for night) then use a flying or aquatic pal to ride across to it.
If you haven't been in a wildlife sanctuary before, be aware that you need to avoid the patrol craft flying around by staying out of their red spotlights when you're inside the dome. The resource node you're looking for is a skeleton, specifically a ribcage, which you can mine to get Ancient Bone.
You can use any mining tool, including pickaxes, though I'd suggest something faster if possible as you'll have a limited mining window while trying to avoid the patrolling ships and the hostile pals who live on the island.
