Rabbits

One day, a rabbit managed to break free from the laboratory, where he had been born and brought up. As he hopped away from the fencing of the compound, he felt grass under his little feet and saw the dawn breaking for the first time in his life.
"Wow, this is great," he thought. It wasn't long before he came to a hedge and, after squeezing under it he saw a wonderful sight: lots of other rabbits, all free and nibbling at the lush grass.
"Hey!" he called. "I'm a rabbit from the laboratory and I've just escaped. Are you wild rabbits?"
"Yes. Come and join us," they cried. He hopped over to them, and started eating the grass. It tasted so good.
"What else do you wild rabbits do?" he asked.
"Well," one of them said. "You see that field there? It's got carrots growing in it. We dig them up and eat them." This he couldn't resist and he spent the next hour eating the most succulent carrots. They were wonderful.
Later, he asked them again, "What else do you do?"
"You see that field there? It's got lettuce growing in it. We eat them as well." The lettuce tasted just as good and he returned a while later completely full.
"Is there anything else you guys do?" he asked.
One of the other rabbits came a bit closer to him and spoke softly. "There's one other thing you must try. You see those rabbits there," he said, pointing to the far corner of the field. "They're girls. We shag them. You really must try it."
Well, he spent the rest of the morning screwing his little heart out until, completely spent, he stagger-hopped back over to his new friends. "That was fantastic," he panted.
"So are you going to live with us then?" one of them asked.
"I'm sorry, I had a great time but I can't."
The wild rabbits all stared at him, a bit surprised. "Why? We thought you liked it here."
"I do," he replied. "But I must get back to the laboratory. I'm dying for a cigarette."