sharks

an old shark was swimmin' the ocean with his grandson by his side when they suddenly see a sinkin' ship which obviously left people defenseless in the waters
the younger shark says:
-look! grandpa! should we go now and eat all that people?
-wait my son, we first must swim in circles around them just letting them see a very blurry shape of ourselves
So they swim around the people 4 or 5 times
then the older shark says
-it's time for us to go, swim around them allowing them to see the full shape of our bodies
a while later he adds:
-now is time to eat them.
when they're leavin' the younger asks:
-why did we had to swim around them that many times?
-my son, people tastes better when the shit is not inside