Researchers propose a new label for humpback whales based on their findings: tool users. While it has long been known that humpback whales form “bubble-nets” for hunting, recent studies reveal that these creatures not only make these nets but also expertly manipulate this remarkable technique in various ways to enhance their food gathering in the feeding areas of Alaska.
In a new study published today in Royal Society Open Science, scientists from the Marine Mammal Research Program (MMRP) at the UH Hawai’i Institute of Marine Biology (HIMB) and the Alaska Whale Foundation (AWF) have introduced a fascinating new idea that designates humpback whales as tool users. Previously recognized for creating “bubble-nets” during hunts, researchers have discovered that these whales are not merely creators of these nets; they skillfully handle this exceptional tool in diverse methods to increase their food intake in the Alaskan feeding grounds. This groundbreaking research clarifies a behavior crucial to their survival and argues strongly for including humpbacks in the rare category of species that fabricate and utilize their own tools.
“Numerous animals utilize tools to assist them in finding food,” states Professor Lars Bejder, co-lead author of the research and MMRP Director, “but very few are capable of creating or altering these tools by themselves. We uncovered that individual humpback whales in southeast (SE) Alaska design intricate bubble nets to catch krill, which are small shrimp-like organisms. These whales adeptly blow bubbles in patterns that create nets with internal rings, manipulating aspects such as the number of rings, the net’s size and depth, and the spacing between bubbles. This advanced method enables them to capture as much as seven times more prey during a single dive without expending additional energy. This remarkable behavior positions humpback whales among the rare group of animals that produce and utilize their own hunting tools.”
Effective hunting is essential for the survival of these whales. The SE Alaskan population of humpback whales migrates to Hawai’i for the winter, and their entire year’s energy expenditure hinges on their capacity to secure sufficient food in the summer and fall months in SE Alaska. Understanding the intricacies of their finely tuned hunting strategy illuminates how migratory humpback whales gather enough calories for their journey across the Pacific Ocean.
Innovative Tools & Collaboration Are Key to Unraveling Whale Behavior
Cetaceans, which include whales, dolphins, and porpoises, are notoriously challenging to study. Nevertheless, advancements in research tools are paving the way for better tracking and comprehension of their behaviors. In this instance, researchers utilized specialized tags and drones to observe the whales’ movement both beneath and above the water.
“We attached non-invasive suction-cup tags to the whales and deployed drones over solitary bubble-netting humpbacks in SE Alaska, collecting important data regarding their movements underwater,” explains co-author and MMRP researcher William Gough. Although these tools are remarkably capable, mastering their use requires time and expertise. Gough shares, “Studying whales is quite challenging and demands skill and precision for successful tagging and drone operations.”
Conducting research in the remote regions of SE Alaska presented its own set of challenges. “We are extremely thankful to our partners at the Alaska Whale Foundation (AWF) for their profound understanding of the local environment and the whales in the area,” notes Bejder. “This research would not have been possible without our strong collaboration with AWF.”
Further Insights and Enhanced Management Expected
Cetaceans worldwide encounter numerous threats, including habitat loss, climate fluctuations, fishing activities, and pollution from chemicals and noise. Currently, one-quarter of the 92 recognized cetacean species are under threat of extinction, highlighting the urgent need for effective conservation methods. Understanding how these animals hunt is vital for their survival, and insights into this crucial behavior equip resource managers to better monitor and conserve the essential feeding areas necessary for their existence.
“This underexplored foraging behavior is entirely unique to humpback whales,” remarks Gough. “It’s quite remarkable to witness these animals in their natural surroundings, engaging in behaviors that only a select few get to view. It’s gratifying to return to the lab, analyze the data, and uncover their underwater activities once they are out of sight.”
With innovative new tools now available to researchers, a wealth of exciting behavioral discoveries about cetaceans lies ahead. “This comprehensive dataset will allow us to delve deeper into the physics and energy dynamics of solitary bubble-netting,” says Bejder. “Additional data is also being gathered from humpback whales showcasing various feeding behaviors, including cooperative bubble-netting, surface feeding, and deep lunge feeding, facilitating further investigation into the energy landscape and fitness of this population.”
“I find it exhilarating that humpbacks have developed intricate tools to exploit prey clusters that they would not normally be able to reach,” adds Dr. Andy Szabo, AWF Executive Director and co-lead of the study. “It is this behavioral adaptability and creativity that I hope will enable these whales to thrive as our oceans continue to evolve.”
This pioneering research was made possible through support from Lindblad Expeditions — National Geographic Fund, the University of Hawai’i at Manoa, and a Department of Defense (DOD) Defense University Research Instrumentation Program (DURIP) grant.
This study was carried out under a NOAA permit granted to the Alaska Whale Foundation (no. 19703). All research complied with institutional IACUC approvals.
