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.
-
Oct 10, 2026, 07:22Poppy Clarke: Turning Steps Into Support for Thrombosis Awareness
-
Oct 10, 2026, 07:12Hamzah Khan: The Role of Genuine Curiosity in Driving High-Impact Academic Research
-
Oct 10, 2026, 06:58Nita Radhakrishnan: Turning Evidence Into Action for Hemophilia Care in India
-
Oct 10, 2026, 06:48Nutan Kaushik: HemeNext 2.0 Brings Global Perspectives to Hematology
-
Oct 10, 2026, 06:43Suthesh Sivapalaratnam: Advancing Bleeding Disorder Care at EHC 2026
-
Oct 10, 2026, 02:38Brianne D.: Sex Differences in RIPK1 Signaling Following Intracerebral Hemorrhage
-
Oct 10, 2026, 02:17Dino Mehic: Managing Heavy Menstrual Bleeding in Patients with BDUC
-
Oct 10, 2026, 00:34Raphaëlle Dodart: Discussing the Mechanisms of Menstrual Hemostasis
-
Oct 10, 2026, 00:26Barbara Adams Krolak: Discussing the Growing Need for Blood Clot Prevention in Asia