Why do whales breach?

Why Whales Launch Themselves Out of the Water

Breaching — when a whale propels 40% or more of its body above the water surface before crashing back down — is one of the most spectacular behaviors in the animal kingdom. A 40-ton humpback whale launching itself out of the ocean requires an enormous amount of energy, which means breaching must serve important purposes.

Leading Theories

Scientists have proposed several explanations, and the truth likely involves multiple functions:

Communication: The massive splash from a breach creates a loud sound that can travel for miles underwater. Research published in 2017 found that humpback whales breach more frequently when groups are far apart and during rough seas — conditions when vocal communication is harder. This suggests breaching serves as a long-distance signal.

Parasite removal: The force of a whale crashing back into the water can dislodge barnacles, whale lice, and other parasites attached to the skin. While this may not be the primary reason for breaching, it is likely a beneficial side effect.

Play and exercise: Calves and juvenile whales breach far more frequently than adults, suggesting a play element. Young whales may breach to develop muscle strength, coordination, and social skills.

Courtship displays: Male humpback whales breach more frequently during breeding season, potentially to demonstrate strength and fitness to females or to intimidate rival males.

Surveying surroundings: By lifting their heads above water (a behavior called “spy-hopping”), whales can visually scan their environment. Full breaches may provide brief aerial views of their surroundings.

Which Whales Breach Most?

Not all whale species breach equally:

Species	Breach Frequency	Style
Humpback whale	Very frequent	Full body, dramatic
Right whale	Frequent	Full body
Gray whale	Moderate	Partial body
Sperm whale	Occasional	Partial body
Blue whale	Rare	Partial body
Orca	Moderate	Full body

Humpback whales are the champion breachers — they have been observed breaching dozens of times in succession. Their long pectoral fins (up to 16 feet) may give them extra propulsion.

The Physics of Breaching

For a whale to breach, it must accelerate to approximately 18 mph (29 km/h) underwater, angling upward at about 30 degrees. For a 40-ton humpback whale, this requires an estimated 8,000 watts of power — comparable to a small car engine at full throttle. The whale beats its tail flukes rapidly to build speed before erupting from the surface.

The energy cost of a single breach is substantial, which is why scientists believe it must serve genuine biological purposes rather than being purely random behavior.