do aliens bleed?

Well if aliens do in fact bleed, i wonder what color it is.

As taken from wikipedia:

"In humans and other hemoglobin-using creatures, oxygenated blood is bright red. This is due to oxygenated iron-containing hemoglobin found in the red blood cells. Deoxygenated blood is a darker shade of red, which can be seen during blood donation and when venous blood samples are taken. However, due to skin pigments, blood vessel coverings and an optical effect caused by the way in which light penetrates through the skin, veins typically appear blue in color. This has led to a common misconception that venous blood is blue before it is exposed to air. Another reason for this misconception is that medical charts always show venous blood as blue in order to distinguish it from arterial blood which is depicted as red on the same chart. The rare condition sulfhemoglobinemia results in green blood.

So what color is alien blood exactly? Red? Blue? Green? or possibly they lack blood all together?
Does anyone have an idea?

There is one pic of an alien that had been shot in the head and a gaping hole is opened up in the back of its head. The blood and crap comming out of it was red.
Remember its whats on the inside that counts =P

wow so if that pic is authentic i suppose that whatever 'color' their blood is, when oxygenated it becomes red.

I'd be content just seeing an authentic pic of an ET.

"If it gets in your way, run it over. If it gets back up, take it home to meet your mother." -- PJ Slug

[edit on 8/11/2007 by pjslug]

Since no one else will say it, I will. The quote from predator, " If it bleeds, we can kill it."

Anyway, as suggested, the color may have to due with anatomy. They could breathe the Earth's atmosphere and not be using the oxygen. It would say a lot about their origin and relation to humans.

Asking this question without knowing if aliens exist is somewhat strange. Different creatures could, if they had blood at all, have blood of almost any color. In theory, that is.

Maybe they dont even have blood at all? Who's even to say they indeed have hearts? Could be all sorts of different things, after all they are aliens

I think they do. All of the 'aliens' we've heard of or run into have been generally humanoid in form. Bipedal symmetrical beings with two eyes, a mouth, arms, etc. The fact that their external biology is set in the same pattern as ours would lead me to believe that they have a somewhat similar internal structure as well. They might have a better cardiovascular system or a different network of veins and arteries but most life we see tends to need a circulation of chemicals and energy to maintain stasis and survival.

I think the color would depend on the chemical composition of their blood and how it interacts with light. It could be black or white, absorbing or reflecting all color, who knows? Maybe it's invisible to us, like our atmospheric sea of air.

There is reason enough to think that idf our bodies require sustanance to be distributed to our tissues and organs that theirs would have similar systems. Maybe not identical, but most life here has a form of a circulatory system or another.

whatever the color is, I'm quite sure that if flows...
maybe expectations are for similarities to human beings to connect us together as part of the great consciousness...

nice question however we will never know until the fleece is removed from the world's public eyes or one of these aliens volunteer the info

Originally posted by kurtcobainuk
Maybe they dont even have blood at all? Who's even to say they indeed have hearts? Could be all sorts of different things, after all they are aliens

Was thinking something similar.

They only bleed if they are organic! Not sure if intergalactic 5w/90 would be considered blood.

Wish I had a better memory, but remember reading somewhere that a different element than iron could also be used as an oxygen carrier. This oxygenated carrier would be a different color than red (red rust of mars is iron oxide I think, again blasted memory). So if they bleed its possible to be a different color than red based on their evolutionary path.

Would speculate about a chlorophyll based physiology, but don't think any intelligent beings could be sustained on the ATP derived from photosynthesis. But who knows. If thats the case they could leak out any number of colors. Blue and Yellow being less likely than the obvious green.