Whales Are Sprinters: What a Blue Whale's Heart Does When It Lunge Feeds

What happens to the heart of the largest animal on Earth when it charges into a swarm of krill? Dr. Ashley Blawas, a postdoctoral scholar in Jeremy Goldbogen's lab at Stanford's Hopkins Marine Station, joins Andrew to unpack new research published in PNAS that measured the heart rates of lunge-feeding blue whales and humpback whales using suction-cup ECG tags.

Ashley explains the three phases of lunge feeding (accelerate, engulf, filter) and why these giants behave a lot like human sprinters. Their heart rates stay high after each lunge, then gradually recover while they glide and filter, refuelling muscles for the next burst. She also shares how body size gives big whales a heart rate range of roughly sevenfold, compared with about threefold in humans, which may be one of the keys to life at the largest scale.

Along the way, Ashley tells the story of how beach vacations in North Carolina and a biomedical engineering degree at Duke led her to whale physiology, how COVID pushed her PhD into molecular research, and where this work is heading next. Think minke whales, North Atlantic right whales, and one day a "smartwatch" that could help track whale health over time.

Takeaways

• Lunge feeding has three phases: acceleration (about 4 m/s), engulfment (a few seconds), and filtering (up to 1 to 1.5 minutes in the largest blue whales).
• Blue and humpback whale heart rates mimic human sprinters, staying elevated after a lunge and recovering gradually.
• That elevated heart rate likely helps oxygenated blood restore energy stores between lunges.
• Big whales access a heart rate scope of roughly 5 to 35 bpm, about sevenfold, versus about threefold in humans.
• Data came from nine tag records on blue and humpback whales across multiple field seasons.
• Tags attach with suction cups from a roughly 6 m carbon fibre pole and record for about 12 to 36 hours.
• Lunge feeding only pays off when prey patches are dense, which makes finding those patches a survival issue.
• Future work targets minke whales, ram-feeding right whales, and long-term health indicators like heart rate variability.

Links for Ashley's Work:
The PNAS paper discussed in the episode: Sprint-like cardiac dynamics support repeated acrobatic lunges in foraging rorqual whales
Ashley's website: ashleyblawas.com
Goldbogen Lab: goldbogen.stanford.edu and whales.stanford.edu

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