Whales are so huge that it's sometimes hard to wrap your brain around that notion that they sustain themselves on teeny-tiny krill. Maybe that's why they tend to be choosy about when they eat.
This April 2017 video from Oregon State University captures a rare and stunning view of blue whales' feeding behaviors. With a drone, researchers were able to watch whales decide when they were going to eat. You can see the whales turn on their sides and then lunge up to swallow up some delicious krill ... when the krill patch is large enough.
The decision to feed or not to feed is most likely dictated by the fact that lunge feeding is an energy-intensive act. As Leigh Torres, an assistant professor at Oregon State University notes on the video, going in for a feeding means the whale has to pump its breaks to eat. After feeding, the whale has to then expend energy getting back up to a good cruising speed. It's a tough choice to make, but it's one that whales seem comfortable making in a split-second. To the latter point, the video also shows a whale thinking about taking a bit out of a small-ish krill patch before changing its mind at the last moment.
This isn't the first time we've gotten different views of whales feeding. Back in September 2016, it was reported that Standford researchers affixed suction-cup cameras on whales to get their perspectives when they're going in for a big krill gulp.