<\/a>\n\t\t\t<\/div><\/figure><\/a>\n\t\t\t<\/div>\n\t\t\t\tIn the first photo, a group of humpback whales surfaces in the middle of a bubble net in Alaska. Mouths agape, the whales gorge on the herring trapped inside the spiral curtain of bubbles. To create the wall of bubbles, one whale\u2014or occasionally two or even three\u2014circles a school of fish in ever-tightening loops while releasing a steady stream of air. (The second photo gives an aerial view of a bubble net made by a different group of whales.) As the bubble net is created, other members of the group perform specialized herding maneuvers that increase the efficiency of the prey capture.<\/p>\n
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In this encounter, I watched a female swim with her young calf (lower center) and a male escort off her right side. As two male challengers moved in to intercept her, the escort charged between the female and the two challengers while blowing a massive bubble trail. Perhaps the bubbles served to partially obscure the female from the challengers or to visually disorient them, but they may have also advertised the escort\u2019s dominance and aggression. Sometimes a challenger responds to such an encounter with a bubble trail of its own. Aggressive males may also release blasts of air bubbles from the mouth.<\/p>\n Christine Gabriele, a researcher with the Hawai\u2018i Marine Mammal Consortium, agrees that this use of bubbles could be considered use of a tool. \u201cAbsolutely,\u201d she says. \u201cThey\u2019ve created a structure out of nothing and are using it in a particular context for what seems to be a purpose that is clear to us.\u201d<\/p>\n In this underwater view, a male escort blows a bubble stream while following a female with two male challengers in pursuit (out of frame). Such a case is \u201cclearly \u2026 an antagonistic signal,\u201d says Sharpe. \u201cHe\u2019s saying, Back off or I\u2019m gonna wallop you! It\u2019s a tool signaling that you\u2019re willing to escalate or you\u2019re pissed or you\u2019re coming in.\u201d And it\u2019s not an idle threat. Competition between male humpbacks for access to females sometimes leads to injury, and, on the rare occasion, to death.<\/p>\n This yearling female humpback approached my boat repeatedly over a period of more than an hour, often blowing sequences of perfectly formed bubble rings. Was she attempting to communicate? Did she want to play? Why did she blow bubble rings only when approaching the boat?<\/p>\n Sharpe notes that in thousands of hours of drone observations of humpbacks interacting only with each other, his pilots have never seen a bubble ring. \u201cHumans trigger this behavior,\u201d he says. \u201cIt\u2019s a play object but it also has an uncanny interspecies component to it.\u201d Humpbacks have only rarely been reported making bubble rings in the northern hemisphere\u2014and there are no reports of it in the southern hemisphere. I feel very fortunate to have seen this behavior twice, 19 years apart.<\/p>\n The same yearling female who created the bubble rings also released massive air clouds a couple of times when approaching our boat. Humpbacks are known to release bubble blasts both from their mouths and from their blowholes. However, these displays are usually produced by adult males during competition for a female. Was this loud and forceful exhalation aggression or play?<\/p>\n California State University Channel Islands professor emeritus Rachel Cartwright, who studies humpback whale mothers and calves in Hawai\u2018i as lead researcher for the Keiki Kohola Project, says that seen from the air, the use of bubbles \u201cseems very orchestrated and purposeful.\u201d Given how often adults use bubbles, she thinks that skill with bubbles would carry an advantage. \u201cAnd that\u2019s often seen by behavioral ecologists as a justification for the costs of \u2018play,\u2019\u201d she says.<\/p>\n<\/a><\/p>\n
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