Researchers say they've figured out what has long been a mystery about certain whales—how they keep from choking when taking in massive amounts of water while feeding. The answer? An "oral plug" at the back of their throats that shifts into place to seal off and protect airwaves, reports Popular Science. Writing in the journal Current Biology, the Canadian researchers say the fleshy tissue—part of the soft palate—appears to be unique to whales, per the New York Times. They made the discovery in fin whales but say it likely applies as well to humpbacks, minkes, blue whales, and all such "rorqual" whales that use a practice called lunge-feeding.
With lunge-feeding, the whales gulp up krill and other prey along with voluminous amounts of water. That's when the new discovery kicks in. "When the animal is breathing, this oral plug sits at the bottom behind the tongue, allowing air to pass from the nasal passage into the lower airways while preventing anything in the mouth from getting through," explains New Atlas. When it's dinner time—that is, lunge-feeding time—the plug "moves up and back, blocking off the nasal passages and opening a path from the mouth to the esophagus. At the same time, a cartilage structure closes off the entrance to the larynx and the lower airways, preventing food or water from reaching the lungs."
Researcher Kelsey Gil, a zoologist at the University of British Columbia, tells the Times that the discovery "fills in a blank that we didn’t even know really existed." However, Popular Science reports on some skepticism, including from one expert not involved with the research who thinks the concept is "very interesting" but who isn't sold the oral plug moves as suggested. Researchers with the study looked at the bodies of 19 fin whales, and the skeptic thinks proof will come only if the mechanism can be observed in a living whale. (Read more whales stories.)