Rare humpback whale behaviour observed in Moreton Bay

By Kara Murphy 12 October 2017
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Tail extension, a mysterious and seldom-witnessed humpback whale behaviour, has been sighted multiple times in Moreton Bay Marine Park this past week.

HUMPBACK WHALES often display behaviours such as breaching, tail slapping, fin slapping, head lunging, and spy hopping. However, migrating humpbacks in Moreton Bay Marine Park, QLD recently exhibited a rarely observed behaviour known as a tail extension, where the whale extends its flukes above the water and, instead of forcefully slapping them upon the water’s surface, leaves them suspended there for a minute or more.

Captain Kerry Lopez of Brisbane Whale Watching has been operating whale watching trips in Moreton Bay for the past 22 years, but says she’s only viewed this behaviour six times – including once this past week, when an adult female extended her flukes for more than 15 minutes.

Other Moreton Bay visitors witnessed similar behaviour. On October 8, three passengers aboard a private vessel (this writer included) watched, mesmerised, as an adult female performed a tail extension three times over the course of an hour. The angle of her flukes created a dish-like shape, with the white fluke undersides facing the sky. Each extension lasted a few minutes, and the female’s calf remained hidden beneath the surface for most of that time; at one point, though, the calf surfaced, swimming close to its mother’s extended flukes.

whale tail extension

A female humpback extends her tail above Moreton Bay’s waters for approximately three minutes in a display known as a tail extension. (Image Credit: Kara Murphy)

One theory is that females could be using this position for nursing. However, Dr. Adam Pack, an expert on marine mammal behaviour at the University of Hawaii at Hilo, has a different opinion.

“I’ve witnessed [tail extension behaviour] in both males and females occasionally in Hawaii, by singleton whales and possibly also by whales in pairs,” Adam tells Australian Geographic.

“[And] I’ve seen a lot of nursing behaviour in Hawaii and have never seen [tail extension] behaviour associated with nursing. Typically in the nursing behaviour, a female [is] horizontal below the surface and the calf latches on to her teat. The calf’s position is typically hanging as it nurses. Nursing is confirmed when either we see the teat prior to or after latch on and/or witness milk escaping from the sides of the calf’s mouth. The mother may be stationary or slowly traveling while nursing is taking place.”

“It is unclear why humpback whales perform the tail extension behaviour,” says Adam. “Like many behaviours, tail extensions may have multiple functions depending on context. One possibility is that this is a way of displacing body heat.”

Regardless of the behaviour’s purpose, sighting it is magnificent – and potentially confusing. From a distance, you might be convinced you’re seeing a beacon of some sort rather than a whale.

Tail extension isn’t the only extraordinary humpback whale behaviour recently recorded in the marine park. On Sunday, October 8, the Brisbane Whale Watching team captured spectacular drone footage of a megapod of 11 humpbacks. And while flying south from Lady Elliot Island to the Gold Coast that same morning, Seair Pacific’s chief pilot Peter Gash and his wife Julie observed and photographed a megapod of 13 whales between Caloundra and Moreton Island – the largest pod they’ve seen in the area. 

whale pod

A megapod of 13 whales were observed near the mouth of Moreton Bay on October 8.(Image Credit: Julie Gash/Lady Elliot Island Eco Resort)