Did you know? Volume Up THE BLOW Gray whales usually surface every 20 seconds as they swim but will often stay under for 3 to 5 minutes when they are eating. If they have been down for 5 minutes, they usually blow 5 times when they surface to replenish their oxygen supply. The blow, or spout, shoots nearly 12 feet high and expels 400 liters of air in a single blast. The whales take a few breaths at the surface then dive again. If they are frightened, they can stay down for 30 minutes, hiding on