Why Do Whales Breach? Reasons Behind Whale Jumps

What is breaching?

Breaching is when a whale swims fast toward the surface and launches much of its body into the air, then falls back with a huge splash. In one large tag study, a leap counted as a full breach when more than 40% of the body left the water. A humpback whale often twists in the air and lands on its back or side, with its long flippers spread.

Breaching is one of several surface behaviors that make noise. Whales also slap the water with their pectoral flippers (pec slapping), smack it with their tail flukes (lobtailing) and throw the rear of the body sideways onto the surface (a peduncle throw). Spyhopping, when a whale rises vertically to look around, is a different, quieter behavior.

The main reasons whales breach

There is no single answer, and the same whale may breach for different reasons at different times. These are the explanations with the most support.

Long-distance communication

The strongest evidence comes from a study of 94 groups of migrating humpbacks off eastern Australia, published in 2017. Researchers watched each group while recording sounds with hydrophones. Whales were much more likely to breach when the nearest other group was more than 4 km (2.5 mi) away than when it was closer. Slapping behaviors, by contrast, were linked to whales joining or leaving groups. The authors concluded that breaching probably helps whales signal to distant groups, while slaps work at short range.

Making a signal heard over noise

The ocean gets louder when the wind rises, because breaking waves add a lot of background sound. A 2010 study of humpbacks off Australia found that as wind speed and noise increased, the whales gradually switched from mostly vocal calls to mostly surface-generated sounds such as slaps and breaches. A splash spreads its energy over a wide range of frequencies, so it is harder to mask than a call, even though it carries less information.

Showing strength and fitness

Breaching is expensive. That makes it a candidate for what biologists call an honest signal: only a whale in good condition can afford to do it again and again. Male humpbacks on the breeding grounds may use breaches as displays to females or rivals, and competitive groups of males are often very active at the surface.

Play, practice and parasites

Calves breach a great deal, often next to their mothers, which may be play, practice, or a way to stay in contact. An old idea is that the impact helps knock off whale lice, barnacles or loose skin. It is plausible, but there is little direct evidence for it, and barnacles cement themselves firmly into the skin.

How much energy does a breach take?

A 2020 study fitted suction-cup tags to whales and recorded 187 breaches by six species, 152 of them by humpbacks. Adult humpbacks reached the surface at an average of about 6 m per second, and some topped 8–9 m per second, roughly 30 km/h (20 mph). They built that speed with only a few powerful tail strokes and lifted on average about 60% of their body out of the water.

In the humpbacks measured, a high breach used more energy than the same whale’s fastest feeding lunge, and the cost rises steeply with body size. A large adult humpback needs many times more energy for one breach than a small juvenile. One juvenile humpback breached at least 69 times over two days, sometimes only seconds apart. Repeated breaching on the breeding grounds is especially costly, because humpbacks eat little there and cannot replace the energy until they return to their feeding areas months later.

Which whales breach the most?

Humpbacks are the best-known breachers, but they are not the only ones. Southern right whales and North Atlantic right whales breach often, and so do gray whales, minke whales and sperm whales. Orcas and many dolphins leap regularly. The tag study above recorded breaches from humpback, minke, sperm, right, Bryde’s and gray whales.

The biggest rorquals, blue and fin whales, breach only rarely. Their long, slender bodies are built for steady cruising and powerful lunges rather than vertical jumps. Large animals other than whales also breach, including basking sharks, great white sharks chasing seals and mobula rays.

When and where to see whales breach

In humpbacks, breaching is most common on the winter breeding grounds and during migration, when whales are social and competing. Good places to watch in winter include Hawaii, Mexico’s Pacific coast and the Dominican Republic. In summer, humpbacks also breach on feeding grounds such as the Gulf of Maine, Newfoundland, Alaska and northern Iceland, though they spend more time feeding there.

A whale that breaches once often breaches several times in a row, so it pays to keep watching the same spot. Groups that are splitting up or meeting other whales tend to be the most active.

Myths and facts about breaching

Myth: a breaching whale is in distress. Breaching is normal behavior for healthy whales. It is not a sign that a whale is sick, stranded or in trouble.

Myth: whales breach to look around. Whales that want to look above the water usually spyhop, rising slowly with the head held upright, rather than leaping.

Fact: breaching is loud. The sound of a large whale hitting the water travels far underwater, which is why it works as a signal. Humpbacks also use sound in other ways, most famously in the songs of the males.