Why can whales hold breath so long?
Show answer & explanation
Answer: Myoglobin stores extra oxygen
Myoglobin stores extra oxygen ✓ — Correct! Whales have high levels of myoglobin, a protein that stores oxygen in muscles. They also slow their heart rate dramatically during dives—some to just 2 beats per minute!
They breathe underwater slowly — Wrong. Whales are mammals and cannot breathe underwater at all. They must surface to breathe air through their blowholes.
Their blood has more iron — Wrong. While blood carries oxygen, the key is myoglobin in muscles. This protein stores oxygen for use during long dives when they can't breathe.
Go deeper: Myoglobin
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