In the vast and mysterious depths of the Pacific Ocean surrounding Hawai’i, a captivating secret about one of its most enigmatic marine inhabitants has been unveiled. Short-finned pilot whales (Globicephala macrorhynchus) have long intrigued scientists due to their deep-diving foraging behavior and elusive lifestyle. Recent groundbreaking research led by William Gough and an international team of marine biologists has shed light on the daily energy demands and feeding strategies of these oceanic dwellers, revealing just how many squid they must consume to survive. Their findings, published in the Journal of Experimental Biology, not only provide critical ecological insights but also reaffirm the resilience of this species in the face of environmental change.
Short-finned pilot whales are fascinating cetaceans known for their extensive diving capabilities, routinely plunging to depths of up to 1700 meters. Despite their widespread distribution, data on their energy consumption and dietary needs, especially in the Hawaiian region, have been conspicuously sparse. The researchers embarked on an ambitious field study to quantify the energetic expenditure and food intake of these whales, critically important for understanding their ecological role and assessing population sustainability given the variability in prey availability.
To accomplish this, the research team employed innovative biologging technology, attaching multi-sensor tags equipped with motion detectors, hydrophones for acoustic data, and even cameras to eight pilot whales. These devices were carefully affixed just behind the whale’s blowhole, an optimal location allowing the recording of echolocation clicks and capturing footage of foraging events. Deploying these tags in the challenging open ocean environment demanded precision timing and skill, especially considering the whales’ quick movements and relatively small size.
The data retrieved from the tags offered a treasure trove of information, as the whales undertook an extraordinary number of deep dives—118 in total across tagged individuals—with maximum recorded depths reaching approximately 864 meters. These dives are essential components of the whales’ hunting strategy, allowing them to locate and capture their preferred prey: squid. On average, each whale performed nearly 39 such dives daily, highlighting a significant commitment of energy to sustain their metabolic needs.
Analyzing the whales’ tail beat patterns in relation to dive depth, the scientists calculated energy expenditure using well-established biomechanical models. They determined that short-finned pilot whales use approximately 73.8 kilojoules per minute during their intense dives, whereas their energy usage drops to 44.4 kilojoules per minute when swimming near the surface. These values offer unprecedented precision in understanding whale metabolism in situ and provide a basis for calculating the amount of prey necessary to fuel their activities.
A critical breakthrough came from correlating acoustic data with observed feeding behavior. Squid interception events were identified through characteristic echolocation clicks captured by the hydrophones. The researchers estimated that each dive yielded consumption of roughly four squid, each providing around 560 kilojoules of energy upon digestion. This calculation bridges the gap between physical exertion and dietary requirements, highlighting the necessity of constant foraging to meet the whales’ metabolic demands.
Synthesizing all the collected data, the study estimated that individual Hawaiian short-finned pilot whales consume between 82 and 202 squid daily. On an annual basis, this translates to an astonishing 73,730 squid per whale. Scaling this up to the population level, with the local population estimated at up to 8,000 individuals, the total squid consumption reaches an enormous figure of approximately 88,000 tonnes per year. Remarkably, despite this apparently prodigious predation pressure, the local squid population remains robust, suggesting a sustainably balanced ecosystem.
These findings present a compelling narrative of ecological equilibrium in Hawaiian waters, where short-finned pilot whales appear to thrive with abundant natural resources. The ability of the whales to meet their significant energy needs reflects both the richness of the habitat and the efficiency of their specialized hunting strategies. Indeed, the research underscores the crucial interplay between predator and prey in marine ecosystems and highlights the importance of high-resolution biologging techniques in informing conservation efforts.
Moreover, the study’s insights have broader implications for the monitoring and management of cetacean populations globally. Understanding the daily energetic costs and prey requirements of marine mammals is vital when predicting their responses to changing ocean conditions, including fluctuations in prey abundance due to climate change or human impacts such as fishing. The Hawaiian short-finned pilot whale population’s apparent health provides a hopeful case study in ecological adaptation and resilience.
William Gough, the principal investigator, expressed optimism about the prospects for Hawaiian pilot whales, emphasizing that their continued survival depends on maintaining the delicate balance between their energetic needs and prey availability. He highlights that such research provides foundational knowledge to anticipate and mitigate future risks, ensuring that conservation strategies are informed by robust, empirical data rather than speculation.
This extensive study represents a significant advance in marine biology and cetacean ecology, illustrating how interdisciplinary collaborations and cutting-edge technology can unlock the secrets of elusive species. As short-finned pilot whales continue to captivate human imagination, this new understanding of their daily lives enriches our appreciation of their complexity and ecological significance.
In conclusion, the successful quantification of energy expenditure and squid consumption by Hawai’i’s short-finned pilot whales not only illuminates fundamental biological processes but also strengthens the scientific foundation for protecting these majestic creatures. Going forward, such detailed ecological assessments will be crucial in enabling adaptive management and conservation of marine mammal populations in increasingly dynamic oceanic environments.
Subject of Research: Animals
Article Title: Daily energetic expenditure and energy consumption of short-finned pilot whales.
News Publication Date: 13-Nov-2025
Web References: http://dx.doi.org/10.1242/jeb.249821
References: Gough, W. T., Madrigal, B. C., Hollers, A., Currie, J. J., Baird, R. W., West, K. L., Fahlman, A., Fish, F. E., Evans, L., van Aswegen, M., Stirling, B., Pacini, A., Olson, G. L., Stack, S. H., Blawas, A. M., Walker, W. A., & Bejder, L. (2025). Daily energetic expenditure and energy consumption of short-finned pilot whales. J. Exp. Biol., 228, jeb249821. https://doi.org/10.1242/jeb.249821
Image Credits: HIMB Marine Mammal Research Program
Keywords: short-finned pilot whales, Globicephala macrorhynchus, squid consumption, energetic expenditure, biologging, deep diving, marine mammal ecology, Hawaiian waters, cetacean foraging behavior, predator-prey dynamics, marine conservation, metabolic rate
