The Explainer: Why Do Humpbacks Breach?

We’re at the height of humpback whale season, when our annual, seasonal visitors return to Maui to mate and birth their young. The shallow, warm waters between Maui County’s four islands are the largest humpback breeding ground in the northern Pacific. 

Visitors and locals alike can use whale season to mark the arrival of the holidays, or as a reason to take a whale-watch tour or simply marvel at these amazing marine mammals from afar.

Courtesy Maui Activities & Tours / Wikimedia Commons

Their most spectacular display is, of course, the breach, wherein whales leap from the sea in an incredible display of strength and return the water with a massive splash.

Which brings us to the question: Why do they do it?

For years, the scientific consensus was, “we’re not sure.” Stunning fish to eat? Warding off predators? To shed barnacles? Because it’s fun? Just showing off?

A study in the journal “Marine Mammal Science” concluded there is one definitive answer: communication. The splashes they create send sound through the water, which sends a message to other whales who may be far away.

“The probability of observing this behavior decreased significantly when the nearest whale group was within 4,000 meters compared to beyond 4,000 meters,” according to the study. “Involvement in group interactions, such as the splitting of a group or a group joining with other whales, was an important factor in predicting the occurrence of pectoral, fluke, and peduncle slapping.”

So, the next time you see a humpback splash, that’s just them talking. Maybe flirting.

Just make sure you keep your distance.

Jacob Shafer