"Fishing safety" joke

A couple of young fellers were fishing at their special pond off the
beaten track when out of the bushes jumped the Game Warden.
Immediately, one of the boys threw his rod down and started running
through the woods like a bat out of hell, and hot on his heels came
the Game Warden...
After about a half mile the fella stopped and stooped over with his
hands on his thighs to catch his breath and the Game Warden finally
caught up to him...
"Lets see yer fishin' license, Boy!!" the Warden gasped.
With that, the fella pulled out his wallet and gave the Game Warden
a valid fishing license.
"Well, son," said the Game Warden, "you must be about as dumb as
a box of rocks! You don't have to run from me if you have a valid
license!"
"Yes, sir," replied the young feller, "But my friend back there,
well, he don't have one..."