William Aird/X
Aug 6, 2025, 10:58
William Aird Explains Why Whales and Dolphins Lack Factor XII
William Aird, Professor of Medicine at Harvard Medical School, shared a post on X:
“WHALES AND DOLPHINS LACK FXII
Why?
In water, wounds aren’t exposed to soil (a natural FXII activator), and diving increases thrombosis risk.
FXII isn’t needed for hemostasis but is prothrombotic. Evolution did the math and deleted it.”
Read The Blood Project here.

Stay updated on the latest with Hemostasis Today.
-
Apr 13, 2026, 04:49Danielle Boyle: This Consultation Is an Opportunity for The Entire ITP Community to Be Heard
-
Apr 13, 2026, 04:18Stephen Cornelissen: You Might Be Eligible to Donate Blood – Here’s Why It’s Worth Checking
-
Apr 13, 2026, 04:12Angie Read: A Powerful Conversation on Survival, Recovery, and Purpose on Stroke Sisters’ Latest Episode
-
Apr 13, 2026, 04:04Ramy Abdelnaby: Telestroke Rounds Show Superior Guideline Adherence in Subacute Care
-
Apr 12, 2026, 22:12Maciej Banach: The ‘Metastatic’ Cardiovascular Threat We Can No Longer Ignore
-
Apr 12, 2026, 21:52Umar Jawed: The Most Dangerous Anti-D Result Is Not the Highest One – It’s the One You Underestimate Early
-
Apr 12, 2026, 21:37Demosthenes Panagiotakos: Hellenic Atherosclerosis Society Calls for Papers on Innovative Strategies in Atherosclerotic Plaque Management
-
Apr 12, 2026, 21:24Heghine Khachatryan: Diagnosing PNH in Resource-Limited Settings
-
Apr 12, 2026, 21:15Katariina Öörni: Role of Cholesterol Absorption Efficiency in Atherosclerosis