Humpback whales build “bubble nets” to catch more prey in a single dive

Although tool-making is often associated with human intelligence, it is not unique to our species. As it turns out, the majestic humpback whales are also tool makers—albeit in their own unique way.

​​Researchers from the Hawaiʻi Institute of Marine Biology (HIMB) and the Alaska Whale Foundation (AWF) have caught humpback whales making a unique tool.

By producing a series of bubbles, this marine species creates a bubble net that allows it to catch seven times more prey in a single dive.

With this documented behavior, humpback whales have earned a place in the select club of creatures known for making their own kind of tools.

“Many animals use tools to find food. But very few make or modify these tools themselves. We found that solitary humpback whales in southeast Alaska make complex bubble nets to catch krill, tiny shrimp-like creatures,” said Lars Bejder, co-lead author of the study and director of the Marine Mammal Research Program (MMRP).

“This impressive behavior places humpback whales among the rare group of animals that make and use their own tools for hunting,” Bejder added.

Other well-known animals include chimpanzees, crows, bottlenose dolphins and African elephants, to name a few.

Unique air cushion nets

Humpback whales have long been observed building bubble nets for hunting.

According to the latest study, these marine creatures use these nets to maximize their catch of prey in Alaskan waters. To optimize the catch, they change the size, shape and depth of the net.

“These whales skillfully blow bubbles in patterns that form nets with internal rings, actively controlling details such as the number of rings, the size and depth of the net, and the distance between the bubbles. This method allows them to catch up to seven times more prey in a single dive without expending additional energy,” Bejder explained.

Whales are incredibly difficult to study due to their elusive nature, but advances in technology have allowed researchers to track and understand their behavior both above and below the water’s surface.

The team used individual markings to identify this new hunting activity.

“We placed noninvasive suction cup tags on whales and flew drones over solitary humpback whales in southeast Alaska that were caught with bubble nets, collecting data on their underwater movements,” said William Gough, co-author and MMRP researcher.

“Whales are a difficult group to study and successfully tagging and/or using drones requires skill and precision,” Gough added.

This strategy can help with migration

Researchers have gained insights into how migratory humpback whales obtain the energy they need to cross the Pacific.

These whales migrate from their wintering grounds in Hawaii to Southeast Alaska. Their feeding during the summer and fall months is important for their survival year-round.

Whales belong to the cetacean group, which also includes dolphins and porpoises. This group faces a barrage of threats, including habitat loss, climate change, fishing pressure and pollution.

According to the press release, a quarter of the 92 known whale species are threatened with extinction, so immediate and effective conservation measures are needed to protect the species now.

By studying their hunting habits, scientists can better protect their feeding grounds and ensure their survival for future generations.

Thanks to innovative research instruments, many more fascinating discoveries about whale behavior are possible in the future.

“This is a rich dataset that will allow us to learn even more about the physics and energetics of solitary bubblenet fishing,” Bejder added. “There are also data from humpback whales engaging in other feeding behaviors, such as cooperative bubblenet fishing, surface feeding, and deep lunging, allowing further exploration of the energetic landscape and fitness of this population.”

The results were published in the journal Royal Society Open Science.