The Blue whale is the largest animal ever known to have existed, measuring up to 108 feet long and weighing in at a massive 180 metric tons. Subsiding almost exclusively on krill, adult Blue whales can eat up to 40 million of the creatures in a day. This whale has been gathering food deep within the water column and reaches the surface with the throat pleats still distended, forming an enormous pouch. The whale is laying on its side, a pectoral flipper visible above. Within a few moments the whale will right itself up, expell the water, swallow the food, take several breaths, and dive again.