A little rabbit was sitting in a field, scribbling on a pad of paper, when a fox came along. "What are you doing, little rabbit?"

"I'm working on my dissertation," said the rabbit.

"Really?" said the fox. "And what is your topic?"

"Oh, the topic doesn't matter," said the rabbit.

"No, tell me," begged the fox.

"If you must know," said the rabbit, "I'm advancing a theory that rabbits can eat many quite large animals - including, for instance, foxes."

"Surely you have no experimental evidence for that," scoffed the fox.

"Yes, I do," said the rabbit, "and if you'd like to step inside this cave for a moment I'll be glad to show you." So the fox followed the rabbit into the cave. About half an hour passed. Then the rabbit came back out, brushing a tuft of fox fur off his chin, and began once more to scribble on his pad of paper.

News spreads quickly in the forest, and it wasn't long before a curious wolf came along. "I hear you're writing a thesis, little rabbit," said the wolf.

"Yes," said the rabbit, scribbling away.

"And the topic?" asked the wolf.

"Not that it matters, but I'm presenting some evidence that rabbits can eat larger animals - including, for example, wolves." The wolf howled with laughter. "I see you don't believe me," said the rabbit. "Perhaps you would like to step inside this cave and see my experimental apparatus."

Licking her chops, the wolf followed the rabbit into the cave. About half an hour passed before the rabbit came out of the cave with his pad of paper, munching on what looked like the end of a long gray tail.

Then along came a big brown bear. "What's this I hear about your thesis topic?" he demanded.

"I can't imagine why you all keep pestering me about my topic," said the rabbit irritably. "As if the topic made any difference at all."

The bear sniggered behind his paw. "Something about rabbits eating bigger animals was what I heard - and apparatus inside the cave."

"That's right," snapped the rabbit, putting down his pencil. "And if you want to see it I'll gladly show you." Into the cave they went, and a half hour later the rabbit came out again picking his teeth with a big bear claw.

By now all the animals in the forest were getting nervous about the rabbit's project, and a little mouse was elected to sneak up and peek into the cave when the rabbit's back was turned. There she discovered that the mystery of the rabbit's thesis had not only a solution but also a moral. The mystery's solution is that the cave contained an enormous lion. And the moral is that your thesis topic really doesn't matter - as long as you have the right thesis advisor.