Humpback Whales Keep Gaping for No Apparent Reason

Humpback whales are among the most observed animals on the planet. Their migrations bring them close to shore. Tourists swim alongside them. Drones film them from above. Scientists have catalogued their songs, their feeding, their social lives.

Researchers went through 66 social media videos and photographs of humpback whales with their mouths wide open, collected from Australia, Hawaii, Tonga, French Polynesia, and the Dominican Republic. The whales weren't feeding. In adults, nobody can say why it's happening. One calf swam continuously with its mouth open for fifteen minutes. Another clapped its jaw shut repeatedly to make a sound.

Four explanations have been proposed: social display, jaw stretching, playing with debris, or simple gravity pulling the mouth open during surface activity. All are plausible. None are confirmed.

Tourists have been filming humpback whales for decades. Scientists scrolled through the footage and flagged their gaping mouths as unexplained.

Read the full story at Animal Behavior and Cognition, 2026

Hot Take: Remember when your mom told you, "close your mouth; you'll catch flies"? Apparently mouth gaping is a thing with our cetacean friends too.