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They say what doesn't kill you makes you stronger. But sometimes what makes you stronger can kill you, at least when it comes to blood clotting². Because the stickiness that allows platelets to heal your wounds also raises your risk of heart attack. 

 

All mammals use platelets to help prevent blood loss after traumatic injury. But birds don't have 'em, nor do reptiles³ or fish. Instead, these critters have blood cells called thrombocytes, which are about twice the size of platelets. But is bigger necessarily better when it comes to clotting? Scientists took thrombocytes from parakeets and put them to the test. The work appears in the journal Blood.

 

They focused their attention on birds because our feathered friends have a cardiovascular system much like our own, in that blood exerts pressure on the blood vessel⁴ walls. 

 

The results: parakeet thrombocytes don't stick together like platelets do. They also don't block blood flow in the birds' arteries⁵ the same way that platelets do when they form clots⁶ in mice. 

 

Which means that mice may be more likely to survive a bloodletting-pecking. But birds are far less likely to suffer from the clot¹ forming economy class syndrome—despite being frequent fliers.

 

Thanks for the minute. For Scientific American's 60-Second Science, I'm Karen Hopkin.

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