Big hole

Two guys are walking through the woods and come across this big hole. 

"Wow . . . that looks deep." "Sure does . . . toss a few pebbles in there and see how deep it is."

They pick up a few pebbles and throw them in and wait . . . no noise
"Man. That is REALLY deep . . . here . . . throw one of these great big rocks down there. Those should make a noise."

They pick up a couple football-sized rocks and toss them into the hole and wait . . . and wait. Nothing. They look at each other in amazement.

One gets a determined look on his face and says, "Hey . . . over here in the weeds, there's a railroad tie. Help me carry it over here. When we toss that sucker in, it's GOTTA make some noise".

The two drag the heavy tie over to the hole and heave it in. Not a sound comes from the hole. 

Suddenly, out of the nearby woods, a goat appears, running like the wind. It rushes toward the two men, then right past them, running as fast as it's legs will carry it. Suddenly it leaps in the air and into the hole.

The two men are astonished with what they've just seen . . .

Then, out of the woods comes a farmer who spots the men and ambles over. "Hey . . . you two guys seen my goat out here?"

"You bet we did! Craziest thing I ever seen! It came running like crazy and just jumped into this hole!"

"Nah", say the farmer, "That couldn't have been MY goat. My goat was chained to a railroad tie."