Humpback whale (Megaptera novaegangliae) Whales build so-called “bubble nets” as tools to hunt, but researchers from the University of Hawaii and the Alaska Whale Foundation have found that these marine animals not only build bubble nets, but also manipulate these unique tools in a variety of ways to maximize food intake in their Alaskan feeding grounds. This novel study sheds light on a behavior critical to whale survival and makes a compelling case for including humpback whales among the rare animals that manufacture and use unique tools.
Although some animal species use tools to forage, only a few manufacture or modify tools. Humpback whales are one of these rare species, as they manufacture bubble net tools while foraging. Using animal tags and unmanned aerial system technology, Sabo others. Investigating the bubble nets made by solitary humpback whales (Megaptera novaegangliae) while feeding on krill in the Pacific Ocean, whale nets in southeast Alaska. They demonstrate that the nets are composed of internal tangential loops, suggesting that the whales actively control the number of loops, the size and depth of the net, and the horizontal spacing of adjacent bubbles. They argue that the whales adjust structural elements of the net to increase the amount of prey they catch in a single lunge by an average of seven-fold. Image credit: Szabo others., doi: 10.1098/rsos.240328.
“Many animals use tools to find food, but few actually make or modify their own tools,” says Lars Bader, a professor at the University of Hawaii.
“We discovered that solitary humpback whales in southeast Alaska build complex bubble webs to capture krill.”
“These whales expertly blow bubbles in patterns that form nets with internal loops, actively controlling details such as the number of loops, the size and depth of the net, and the spacing of the bubbles.”
“This method allows them to catch up to seven times as many prey in one feeding dive without expending any extra energy.”
“This impressive behaviour puts humpback whales in a rare group of animals that make and use their own tools to hunt.”
The marine mammals known as cetaceans include whales, dolphins and porpoises and are notoriously difficult to study.
Advances in research tools are making it easier to track and understand whale behaviour, and in this case, Professor Bader and his colleagues used specialised tags and drones to study the whale's movements from above and below the water.
“We attached non-invasive suction cup tags to whales in southeast Alaska and flew drones over humpback whales as they hunted alone in bubble nets to collect data on their underwater movements,” said Dr William Goff, also from the University of Hawaii.
“The tools are great, but it takes practice to hone them.”
“Whales are a difficult group to study and successful tracking with tags and drones requires skill and precision.”
“This little-studied foraging behavior is unique to humpback whales.”
“It's really amazing to see these animals in their natural habitat, doing things that only a handful of people get to see.”
“And then it's rewarding to be able to go back to the lab and look at the data and find out what they're doing underwater after they're out of sight.”
a paper The study was published in the journal Royal Society Open Science.
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A. Sabo others2024. Solitary humpback whales manufacture bubble nets as a tool to enhance prey intake. R. Soc. Open Science 11(8):240328;doi: 10.1098/rsos.240328
This article is based on a press release provided by the University of Hawaii.
Source: www.sci.news
