Aliens have a dirt poor pain tolerance.

[Meathead320]

Aliens have a dirt poor pain tolerance. At least when compared to a creature like the Predator.

For some reason, even when confronted with the slightest pain, even if it has no chance of significantly wounding them, let alone killing them; the Aliens seem to have very primitive and childish reactions to pain, from screaming and backing away to getting visibly wildly angry when they are forced to endure pain.

A2: Queen backed her mouth away from the Powerloader torch; she also backed away from the flame thrower at the elevator scene, even though not nearly enough flame was coming out of either to really injure her.

A1: Even good'ol "Skull" backed away from the steam jets he was hiding in, screaming and carrying on like a little girl who didn't get her way.

A4: Backed away from the Liquid Nitrogen jets even though it has been show that they can be completely submerged in it without dying.

AVP: Queen Getting stabbed in her neck with the spear, and instead of just removing it right there, she reared up, took a few steppes back, and fell over into a house before removing it.

A3: Alien was covered in molten lead, I will give it that, but it really had no choice there, although it sure pissed it off. You could say he (Dr.Evil voice) "lost his cool". 

[techtor]

Well, I'd say it makes for a good plot device and so that this "bad guy" isn't so invulnerable.

[SiL]

A1: Even good'ol "Skull" backed away from the steam jets he was hiding in, screaming and carrying on like a little girl who didn't get her way.

Ripley was depressurising the ship, not shooting steam at it. Look over it's shoulder during that scene and you can see a bright flash. Loud noise, heat, being in a cramped space, decompression ... yeah, I'd say it had a right to screeam

[Eidotemit]

totally get what you're saying, though it may be a bit extreme. Sure the aliens can survive those things with little damage, but that doesn't mean that its not painful to them and they thus want to get away from it and scream.

I will give you though that preds do seem to deal with pain much better, though they couldn't really survive what caused the aliens to react like you said. Maybe they would  if exposed for extended periods of time, maybe not.

[SiL]

Preddie wailed like a bitch when he put the clamp on his leg in Predator, and when he stuck himself with a needle in Predator 2

[Pax]

Well, there have been some theories that Aliens communicate with sound and see through echolocation.  Maybe they're not whining about the pain, maybe they're increasing the volume so they can get a better picture of the threat, and warning (or summoning) other aliens in the area.

Also, they seem to thrive on their prey's fear.  Perhaps it makes sense that a corresponding aggressive response puts them off a little.

-Pax

[Hankerson]

The fit that one alien (pre-grid Grid) threw in AVP after the pred' threw it was just unnecessary.

[SM]

Ripley was depressurising the ship, not shooting steam at it.

No I think she was shooting steam (or whatever the gas was) at it.  If she depressurised the ship the Alien wouldn't have shot out when she opend the door.

As for the topic - we don't know if it's pain or annoyance or what.

[Meathead320]

Ripley was depressurising the ship, not shooting steam at it.

No I think she was shooting steam (or whatever the gas was) at it.  If she depressurised the ship the Alien wouldn't have shot out when she opend the door.

As for the topic - we don't know if it's pain or annoyance or what.

Thanks for clearing the steam thing up SM, that is what I thought it was too.