And grays can dive at least 400-feet deep. Usually, grays also expel air and water from their two blowholes prior to diving. The ball and heart-shaped clouds of mist can rise more than 14' high and are often visible more than one mile away. In fact, that's how boat captains often locate migrating grays. However, grays periodically swim up boats and have been known to rub their bodies on a boat's hull.
Some captains think that grays are attracted by the drone of a boat's engine.
At times, the grays will stop in the water, turn on to their side at the surface and slap the ocean with their flippers. Periodically, you also see grays spyhopping, which simply means that they slowly stick their mottled, tapered heads out of the water. The precise reason for spyhopping is not known. But some scientists believe grays surface simply to look around, helping them navigate along the coast. Spyhopping has been witnessed many times off Dana Point, a promontory that may be a navigational landmark for the animals.