The sight of a huge humpback whales breaching is a sight to behold. More than being just a selfie-worthy moment, it serves an essential function for these giants of the ocean.
After studying different groups of humpback whales migrating south along the Queensland coast in September and October of 2010 and 2011, University of Queensland marine biologist Ailbhe Kavanagh and her colleagues discovered that the whales were actually communicating with one another. Their findings were published in the Marine Mammal Science journal.
They found that the whales were more likely to breach when the nearest other whale group was more than four kilometres away. This suggested that this action facilitated communication between distant groups of whales.
In contrast, the action of repeated tail and pectoral-fin slapping often occurred before new individuals joined the group or when the group spilt up, suggested it helped to maintain diplomacy within the group.
On the other hand, the action of repeated tail and pectoral-fin slapping occurred more frequently just before new whales joined the group or if the group split up, suggesting that it was used for close-range communication.
All humpback whales engaged in breaching and slapping behaviour during migration, breeding and feeding, hence underlining the importance of its role in communication.
“Although surface-active behaviours only give very simple information like location, it’s possible that a succession of these surface sounds could convey a little more information,” says Joshua Smith at Murdoch University in Perth, Western Australia.
The scientists also noticed that the whales were more likely to engage in such surface-active behaviour when it was windy.
George Mason University cetacean biologist Chris Parsons, who was not involved in the study, said: "Even though these whales can produce calls that travel great distances, if there’s a lot of noise, it might be easy to drown out. Leaping up in the air and splashing down is equivalent to the really keen kid in a classroom jumping up and down waving his arms.”