Humpback whales are renowned for their spectacular acrobatics, which include repeatedly striking the ocean surface with their massive appendages. Scientists refer to this dramatic surface activity as “percussive behavior,” encompassing lobtailing (tail slapping), pectoral fin slapping, and fluke slapping. The sheer energy expenditure required suggests they serve important functions. Researchers have found the reasons behind this behavior vary widely based on context, age, and immediate social environment. These powerful surface slaps fulfill multiple roles, from long-distance signaling to close-range social interaction and specialized feeding tactics.
The Primary Role: Acoustic Communication
The powerful impact of a fin or fluke on the water’s surface is an effective, non-vocal method of transmitting sound through the ocean. When a humpback whale executes a slap, it creates a loud, low-frequency sound that travels great distances, often farther than their complex vocalizations, particularly in noisy conditions. This surface-generated signal propagates well through the water, functioning as a long-range announcement across the ocean environment. In shallow water, these acoustic signals can establish a communication radius extending up to approximately four kilometers.
This loud, percussive sound is useful for maintaining contact between individuals or groups that are widely dispersed. The slaps help migrating whales locate one another or allow a lone whale to announce its presence. Studies have shown that the physical act of slapping is more common when the nearest neighboring group of whales is several kilometers away, confirming its role in long-distance signaling. Surface-generated sounds are less susceptible to being masked by wind-generated noise compared to underwater vocalizations, making them a reliable form of communication in choppy waters. The sound produced by the impact cuts through the ambient noise, effectively maintaining the social network over significant ranges.
Physical Display in Social Settings
Beyond long-distance signaling, slapping behaviors are frequently employed in immediate, close-range social interactions, where the visual component is as important as the sound.
Courtship and Competition
During the breeding season, pectoral fin slapping is used as a form of courtship. Females sometimes slap their fins to attract the attention of nearby males, often marking the start of a competition pod where multiple males gather to vie for attention. The loud, repetitive nature of the slap serves to initiate social engagement.
In a more aggressive context, slapping acts as a display of dominance and a warning signal, particularly among competing males. Males will use tail slaps and peduncle throws—where the lower body is forcefully slammed down—to show strength and warn rivals to keep their distance. This physical display is used in close quarters to express agitation or aggression in the competition for access to a female. Fluke and fin slapping are also observed in mother-calf pairs, where the behavior may be a form of communication or instruction for the calf to practice surface maneuvers. The distinct, forceful impact can also serve as a warning to potential threats, such as nearby predators or encroaching vessels.
Slapping as a Foraging Tool
Certain types of fin slapping, most notably lobtailing, are specialized tactics used by humpback whales to manipulate their prey, often small schooling fish. This behavior involves the whale raising its tail fluke clear of the water and bringing it down forcefully onto the surface. The resulting loud, sudden percussive sound is thought to disorient, frighten, or momentarily stun the small fish below. The shockwave created by the impact can cause a school of fish to tighten into a denser ball, known as a bait ball.
Consolidating the prey in this manner makes the school easier for the whale to engulf in a single lunge. Lobtailing is sometimes used in conjunction with “bubble-net feeding,” where the whale blows a circular curtain of bubbles underwater to corral fish. By slapping the water, the whale prevents the fish from escaping the bubble net by leaping out, herding them toward the center for consumption. Pectoral fins are also actively used in some feeding strategies to herd or guide fish back toward the mouth, a technique called pectoral herding, which reinforces the bubble net structure.