They their attention on birds because our friends have a cardiovascular system much like our own, in that blood exerts pressure on the blood walls. The results: parakeet thrombocytes don’t stick together like platelets do. They also don’t block blood flow in the birds’ arteries the same way that platelets do when they form clots 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 clot formation called economy class syndrome -- despite being frequent fliers.