Why doesn't zombie blood coagulate?

Question

In The Walking Dead (as opposed to the book World War Z, for instance), it has been consistently shown that zombies have red, liquid blood, apparently indistinguishable from human blood.

But we know that zombies are dead, and their circulatory system is no longer functional. As such, one might be forgiven for assuming that their blood would have coagulated shortly after they died - which is precisely what happens when a person dies in real life. In the aforementioned World War Z novel by Max Brooks, zombies have thick, solid, black, congealed blood, much like a dead human being does.

Why do the zombies on The Walking Dead retain their liquid blood? Shouldn't a person's blood coagulate upon death, and remain coagulated after reanimation?

Answer 1

https://en.wikipedia.org/wiki/Disseminated_intravascular_coagulation

DIC is an effect of some Hemorrhagic viruses; basically it causes mini-clots which deplete platelets and have the net result of reducing blood's ability to clot. There are many enzymes and chemicals that could keep blood liquid for a long time; I chose the above simply because it is something real-world viruses are definitely capable of. It doesn't explain why zombies only need a brain to keep moving; but it is plausible that DIC, or a related viral mechanism, could keep the contents of their skull wet and splatter-able...

Answer 2

It's established in S01E06 "TS-19" that zombies in The Walking Dead are, as Miracle Max might put it, only mostly dead. They're shown as having brain activity, mostly centered in the cerebellum (which controls heartbeat), so it seems possible that your assertion "we know... their circulatory system is no longer functional" is inaccurate and their blood is kept liquid by some modicum of continuing circulatory function.