These divers had an incredibly close encounter with two humpback whales recently, while exploring the waters of Central California's Souza Rock.
The divers, understandably, lose it. Humpbacks tend to have this effect on people. Though, for as dramatic as this video is, the divers were at little-to-no risk of being swallowed whole. Humpbacks subsist not on large prey but very small marine life, which they strain through filter-like "mouth hairs" called baleen. The biggest baleen whales on Earth (humpbacks, fin whales and blue whales among them) are called rorqual whales. The blue whale, in particular (which is not only the biggest rorqual of all, but the biggest animal to have ever lived), is known for having a throat incapable of accommodating anything bigger than a beach ball. Needless to say, these humpbacks aren't swallowing anybody.
Alright, but weren't these divers still at risk of spending a few uncomfortable seconds inside a staggeringly capacious whale-maw? Well... probably not.
The whales in the video are employing a technique known as lunge feeding. In a matter of seconds, each whale opens and closes its mouth around a massive swarm of prey while swimming toward the ocean surface. An 80,000-pound animal swinging its jaws to and fro may strike you as aimless and haphazard, but the truth is it's actually a remarkably deft and well-coordinated action. Last year, in fact, researchers led by paleobiologist Nick Pyenson announced the discovery of a previously unknown sensory organ, located in the chins of rorqual whales, that they believe may be essential for coordinating this behavior.
"Whales are like mammals from space," Pyenson told io9 at the time. "they just have all these strange adaptations to living life in the water."