Scientific Breakthroughs

Scientists Uncover Why Whales Leap Into the Air

Scientists Uncover Why Whales Leap Into the Air
PHOTOGRAPH: Zorankovacevic | Photo shows a leaping humpback whale.

Ever wondered if there may be a reason why whales leap high up into the air from the ocean’s surface and crash back into the water, and slap their tails and fins on the way down? Breaching — the behavior of whales to leap and break through the water surface – requires much energy; so scientists set out to verify if it plays a crucial role in the life of aquatic mammals as whales.

When whales leap up into the air, they are not signifying happiness nor giving human spectators a big hello. Instead, when they slam their bodies into the ocean water, they may be “talking” to their fellow whales as far as 2.4 miles away. The new insights on whale communication were recently published in in the journal Marine Mammal Science.

The study was conducted by marine biologists from Australia, led by Dr. Ailbhe Kavanagh, who observed 76 groups of humpback whales migrating to the Antarctic from Australia’s Peregian Beach for over 200 hours.  By slamming their massive bodies into the water, the resulting sounds that reverberate like a drum can travel far. The researchers deduced that the patterns of breaching and slapping are a form of long-range and close-range communication.

Factors Influencing Whales’ Surface-Active Behaviors

Little is known about the factors that may be influencing the surface-active behaviors and what their functions might be. The researchers examined the social and environmental contexts in which the humpback whales’ surface-active behaviors occurred.

After continuous acoustic monitoring, and collection of data pertinent to the social and environmental context of each group, the marine biologists ascertained that breaching may play a role in communication between (rather than within) distant groups. The probability of observing such behavior decreased significantly when the nearest whale group was within 4,000 m compared to beyond 4,000 m.

There has been previous research that theorized that the sound made by breaching is used to signal nearby groups. Breaching is more likely to be used for intergroup signaling when wind speeds, and therefore background noise levels, increase.

Apart from water slapping, humpback whales can also make a range of vocal calls including groans, grunts, grumbles, and even barks. Whales may use breaching to communicate under different acoustic conditions compared to vocal signals.

On the other hand, the study noted that fin or tail slapping tends to be more frequent as groups of whales split or come together. It pointed out that communication through water slapping tends to be more frequent when it is windier – possibly because it becomes more difficult to hear vocal calls.

Pectoral slapping is used for close-range or within-group communication by humpback whales, possibly to initiate or mediate splitting. Pectoral slapping behavior is done by whales more to communicate within a group rather than between groups.
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