Video: To be fair, whale sharks don't come in any size other than "huge". That's kind of their thing, being that they're the largest fish species on Earth. How huge are they? How does approximately 12m long and 20,400kg strike you? Lucky for shark biologist Ocean Ramsay who's swimming alongside this one, whale sharks are filter feeders. Rather than gnash into prey like their relatives, they act like living vacuums, sucking in water and whatever edible material comes along with it. Water gets expelled, food bits stay trapped, shark stays happy.
Even if they are mostly harmless, I still wouldn't want to swim too close to that mouth.