Scientists Decode Whales' Extreme Heart Rate Shifts During Deep-Sea Hunts

In the cold depths beneath Monterey Bay, a blue whale's heart slows to nearly nothing — two beats per minute — yet the animal still summons explosive force to hunt. A team led by Stanford marine scientist Ashley Blawas has now measured this paradox directly, attaching ECG tags to blue and humpback whales to reveal how their hearts flex between near-stillness and urgent recovery. The findings, published in PNAS, suggest that the same metabolic logic governing a sprinting athlete governs the largest creatures on Earth — and that a whale's heartbeat may one day serve as a vital sign for the healt