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The Antarctic Icefish Is the Only Known Vertebrate with Transparent White Blood and Zero Hemoglobin

Living in sub-zero Antarctic seas, the icefish uses 1 oversized heart to circulate completely clear blood with no hemoglobin or red blood cells.

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Why / How?

Frigid polar seawater dissolves far more oxygen than warm water, allowing the blackfin icefish to discard hemoglobin genes. To compensate, its single heart is ~4 times larger than normal and pumps clear plasma through wide vessels.

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Questions & Answers (Quick Guess & Key Takeaway)

Quick Guess: How many oversized hearts pump transparent, hemoglobin-free blood inside an Antarctic icefish?

Verified Answer: 1 heart

Quiz Question: How does the Antarctic icefish survive without red blood cells or hemoglobin?

Correct Answer: Cold water holds ample dissolved oxygen carried directly in clear blood plasma

High dissolved oxygen in freezing Antarctic seas plus an enlarged single heart keeps tissues oxygenated.

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How does the Antarctic icefish survive without red blood cells or hemoglobin?

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