Marine biologists have yet to determine exactly why whales jump.
While marine biologists have recently paid attention to endangered whale species, they haven’t done enough research to know exactly why whales jump. A breach occurs when a whale, especially a humpback, launches completely out of the water, twists in the air, and lands loudly on its side. Tourists on whale-watching tours may think that leaping mammals take a break just to create photogenic moments, but it probably has more to do with communication, comfort, defense, or predatory behavior.
Whales may make a breach to scrape up barnacles.
One theory suggests that the whales make their way as an alternative method of communication, rather than their underwater sonar noises. Other whales are likely to be able to hear the slap from a very long distance. However, what the whales say to each other can only be guessed at. Are they warning their friends about abundant food sources? Seductive companions? Or just announcing your presence?
Another theory is that after a breach, a large amount of dead skin and barnacles are released with the impact of landing. Scientists who have tried to track individual whales based on their DNA have noted this convenient way of collecting genetic material. Whether whales intentionally break through to scrape off the top layer of skin, water lice, or barnacles in the same way humans scratch with fingernails is unknown, but it seems plausible.
Perhaps the whales have recently developed their frequent breaches in response to so many barges, boats, ships, and people in the water. Since they have adequate eyesight, they are believed to jump out of the ocean to see and be seen by human-powered vessels. This gives them time to prepare for a moving ship and also warns the ship not to get too close to the area where the whales are gathering. This prevents injury to both parties.
Two lesser-known theories have to do with fast travel and attacking fish. Aerodynamically, letting water flow briefly into the air can help a whale swim fast over long distances. The gap may have energy efficiency aspects. Second, whales may purposely land on prey that they could not otherwise consume without being bitten. The strong impact is known to render prey unconscious long enough for the whale to swallow it.