Once upon a time there was this little deer, eating a freshly-tossed salad by the shores of the sea.
Suddenly, the deer snaps his head seaward, a couple of leaves hanging from his mouth. Fish are frolicking just off the shore; little silvery fish leaping up and down, making little splashes in the calm water.
The leaves fall out of the deer's mouth as his tongue licks his lips. He wants those fish. He wants to eat those fish. He looked left; there was a lemon tree. He looked right; there was a pepper shrub.
"Mmmm mmmm!" he thought to himself, as he ran towards the water and jumped in.
He swam hard towards the fish, his spindly-legs propelling him at barely one knot of speed. A big grin showed on his face. "Why, I could just spear them with my antlers...boy, would that be a hoot!"
The fish were getting closer. More and more were jumping out of the water. The deer's grin got wider, exposing a gleaming, well polished set of lowers. Bits and pieces of the salad between those teeth were washed away.
"Fins!" he cried to himself. "That's what I need! Why, if I can just get a hold of some fins, I could really catch up to those fish. And maybe some new teeth, all up and down. And perhaps a net inside a very big mouth...maybe it could filter out large basketfuls of fishies!"
"I need them NOW!"
He sat still in the water, contemplating what he just said. A change in diet, change in habit, change in look, all needed now if he was ever to catch any fish at all. "It looks like it's going to take some time," he thought to himself. "Maybe a long time. Maybe generations."
"But it starts with me. I am the first, I saw a need to go fishing, and one day I'm going to look like a fish myself."
"By the way, why were those fish jumping?"
The deer looked down and saw a great big shark rising up at him.
Hours later, several other deer gathered on the beach. "I wonder what he was doing out there?"
"I dunno. There's a trail of leaves going to the water...maybe he was washing his food the way the raccoons do in the forest."
"Ah, who cares," said one other. "Maybe we should evolve a way to cross the $^#@ highway without getting hit by a car!"