The blue whale is the most mammoth creature ever to grace the planet, so it might behoove us puny little humans to pay attention to how it sustains its 100-ton-plus mass. Scientist Jeremy Goldbogen monitored some 265 great blues to determine their feeding efficiency (calories expended versus calories gained), reports Discover, and what he found was almost as staggering as the creature itself: A full-size blue plunging through a dense swarm of krill can bag about 1,100 pounds of its prey—or about 457,000 calories—in a single, giant gulp.
The energy the beast expends to get that mouthful is significant: between 770 and 1,900 calories per feeding lunge. But even a smaller whale plunging through less-dense krill still packs in 8,000 calories—meaning the average gain is between eight and 240 times the energy spent. Goldbogen also discovered that during these lunges, the whales accelerate to a top speed of 8 mph in under a minute. If that sounds slow, consider this: Michael Phelps swims the 100m butterfly at just 4.4 mph.