A sheep and a hole [PG]

Two campers are out walking around, and come across a huge hole in the ground. The first camper goes up to the hole and says "wow, I wonder how deep this is?" The second camper picks up a rock, chucks it in the hole, puts his ear down and waits to hear it hit the bottom. Nothing. The first camper says "jeez, it must be really deep!" and picks up a larger rock. Using both hands he heaves it into the hole. The campers put their heads down and listen for the big rock to hit. Nothing! The second camper looks puzzled, and then spots a boulder. "Hey come and help me with this" he says, and they both start lugging the enormous rock to the hole. "3-2-1" both campers shove the boulder into the hole and quickly put their heads down to listen to the impact. Not even 3 seconds go by and a sheep runs and JUMPS into the hole. Both campers look at each other bewildered. "Did you see that?? A sheep just ran and jumped into the hole!" A few minutes pass, and a farmer comes up. The farmer asks "Hey, have you guys seen my sheep?" The first camper says, "Yeah, the craziest thing happened! Your sheep ran, and jumped into this hole!" The farmer laughed, and said "That's impossible! My sheep was tied to a rock."