The logic of great white sharks

[Cancer]

Two great  white sharks, swimming in the ocean, spied a ship in distress.  "Follow me,  son," the father shark said to the son shark and they swam to the ship.  "First we  swim around the people in the water with just the tip of our fins showing." And they did. "Well done, son! Now we swim around them a few more times with all of our fins showing." And they did. "Now we eat  everybody." And they did. When they were both gorged, the son asked, "Dad, why didn't we just eat them all at first? Why did we swim around and around them? "

His wise  father replied, "Because they taste better without the shit inside!"