There has long been a superstition among mariners that porpoises
will save drowning men by pushing them to the surface, or protect
them from sharks by surrounding them in defensive formation.
Marine Studio biologists have pointed out that, however intelligent
they may be, it is probably a mistake to credit dolphins with
any motive of lifesaving. On the occasions when they have pushed
to shore an unconscious human being they have much more likely
done it out of curiosity or for sport, as in riding the bow waves
of a ship. In 1928 some porpoises were photographed working like
beavers to push ashore a waterlogged mattress. If, as has been
reported, they have protected humans from sharks, it may have
been because curiosity attracted them and because the scent
of a possible meal attracted the sharks. Porpoises and sharks
are natural enemies. It is possible that upon such an occasion
a battle ensued, with the sharks being driven away or killed.
Whether it be bird, fish or beast, the porpoise is intrigued
with anything that is alive. They are constantly after the
turtles, who peacefully submit to all sorts of indignities.
One young calf especially enjoyed raising a turtle to the surface
with his snout and then shoving him across the tank like an
aquaplane. Almost any day a young porpoise may be seen trying
to turn a 300-pound sea turtle over by sticking his snout
under the edge of his shell and pushing up for dear life.
This is not easy, and may require two porpoises working together.
In another game, as the turtle swims across the oceanarium,
the first porpoise swoops down from above and butts his shell
with his belly. This knocks the turtle down several feet.
He no sooner recovers his equilibrium than the next porpoise
comes along and hits him another crack. Eventually the turtle
has been butted all the way down to the floor of the tank.
He is now satisfied merely to try to stand up, but as soon
as he does so a porpoise knocks him flat. The turtle at last
gives up by pulling his feet under his shell and the game is over.