A Marine Biologist discovered that he could prolong the life of dolphins
almost indefinitely if they were fed on certain rare species of
sea-gull. Naturally he decided to feed his own dolphins on this diet.

Unfortunately, he began to run out of supplies from the coast and had to
start obtaining his seagulls from an inland lake. This necessitated
crossing a national park filled with sleeping lions.

He carefully moved around the lions on tip-toe so as not to wake them
... However a park ranger came along and arrested him for transporting
gulls across sedate lions for immortal porpoises.