The Famous Barnum, was looking for a new act for the circus. After searching for many years he finally met an old gentleman in a bar who offered him a Gnu for $500.00. This was the first Gnu that Barnum had ever seen and he was sure that it would be a great addition to his troupe. Barnum enquired of the gentleman as to how long the lifespan of a Gnu was and was informed that this one was 40 years old and that they only lived to an average age of 45, however the price was right so Barnum decided that he would easily recoupe his outlay within the first 6 months once he got the Gnu to perform (Jumping through hoop, Sitting up and begging, offering his front hoof to be shaken, rolling over and playing dead etc.).
The problem occured when he tried to get the Gnu to perform any of these tasks. "SIT!" Barnum would commnand. But the Gnu would just stand there with a vacant look in his eyes. "BEG!" he commanded. Still the Gnu just stood there. "ROLL OVER AND PLAY DEAD!" Shouted Barnum. Still no response from the animal.
Barnum never did get the Gnu to perform, and finally sent the animal back to the wilds to live out his days in peace.
The Moral of the Story??
"YOU CAN'T TEACH ON OLD GNU, DOG TRICKS!"