It is normally not possible to go down without the climbing axe, but if you jump carefully on the walls you should be able to go down without trouble. It is also possible to start at the cave 9 exit located here as a shortcut. It is located near the end of the cave, lighted on a wall. The Climbing Axe is located in the Ledge Cave (Cave 9). Be careful though, if you fall into the Sinkhole, You CANNOT get out with the climbing axe! You also can't use it to go down the Sinkhole directly from the the forest floor, the same reason goes as it prevents the player from accessing the end game area during early game. You can't use it to climb rocks, walls, and mountains in the snow biome at the northern side of the Peninsula, this is probably to prevent the player from accessing areas not meant to be gone through, especially the parts of the Sahara Laboratory during early game. When prompted, attach onto a wall by pressing your use button ( E by default). As well as that, they usually have bits of rope attached to the wall, which also act as a guide for climbing, showing where to detach from the wall. Climbable walls generally look flat and have a different color to the other cave walls. The climbing axe allows the player to climb walls, provided they are at a climbable wall. It can be used to chop limbs on cannibals corpses, but cannot be used to chop down trees.
It can be a useful weapon against fast and weak enemies, like starving cannibals. As a weapon, the climbing axe deals less damage than the plane axe, but swings fast like the Katana. It can be used to climb various rocky cliffs on the peninsula and specific walls in the caves.