🤪 Fun & Weirdpublished 2w ago
Starfish survive with seawater instead of blood
Sea stars don't have a single drop of blood in their bodies. Without bone marrow, red blood cells, or a heart, they rely instead on an intricate hydraulic network called a water vascular system. They pull pure seawater in through a sieve-like opening called the madreporite, circulating it through internal canals to distribute vital nutrients and oxygen to their organs—and to power their hundreds of tiny suction-cup tube feet.
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