Here's my opinion, I think ther for balance, alowing them to use ther tales as weapons wile runing and jumping. I think ther not open tubes but closed ones filled with a liqude for stability, like The stuff in your ear.

You don't have to riply to this unless you have an idea.

The tubes with liquid in your ear are for balance. When you move, the liquid does not, this then triggers little hairs which tell your brain that you have moved and in which direction.

They could be used for "breathing", they do have a large surface area.

My stories are based from Anise's ideas, and she had them being used for cooling the alien. A bit like dogs, they can't sweat to cool down, so they need an alternative to prevent overheating. In the queen, these have evolved into long spikes.

One idea is they might be sensory organs, sort of like the antenna on an insect. Aliens either don't have eyes or have just one, and its doubtful this works well in the dark. It is possible this might be a very sensitive nose (both to smell prey and to detect phermones from other aliens) and an ear as well to sense vibrations. They might also release phermones.

And of course, it is possible it is a multi-role structure that does everything everyone has said at one time [img]/images/forum/smilies/icon_razz.gif[/img]

actuly they have six eyes, four hiden and two in ther mouth for lining up head bites. The four are hiden in the dome like part on the front of ther head.

Where did you hear that?

At a fan site, I don't remember witch one but the guy who told me whew alot.
He did not tell me about the spines thouw

My studies indicate that the spines could be used for carrying eggs through-out the hive structure.
A sort of suprise attack.
They could also be used for secreting hive resin. But I don't know....

ok these are the facts that we know from the movie on these issues.
No eyes that we have seen. (except on the newborn mutant thing from resurection)
4 tubes and one spike on the normal drones that we have seen. purpose: unknown.
queens have spikes instead of tubing. purpose: attaching resin supports to queen for egg laying. other then that unknown.
All xenos except for the newborn have had tails. tails with pointed ends and possibly sharp or serated. Purpose: balance for the xeno. rudder and possibly propulsion during swimming. and as the queen demonstrated the tail is also a weapon.

thats all that we know from the movies.

hope that helps.
my suggestion. when doing a story where the xenos are changed maybe do a note on the prologue explaining this.

It is strongly implied in Alien that the alien uses it's tail as a weapon against Lambert.

If any one has the time and energy to go and look at Alien resurection... the scene with them swimming underwater through the kitchen/cafeteria might show what the tubes are for.
I am a little fuzzy on the details, but it did seem that perhaps there was air coming from them as they swam after the humans.
if any one wants to pull out their dvd they can put in on slo mo and take a look to see if air bubbles are coming from them.
If so then they very well could be spiracules, like what earth insects use for breathing.
If not, then its still a mystery

Quote:

If so then they very well could be spiracules, like what earth insects use for breathing.

Insects breath through their skin.

Even in small amphibians like frogs, most of the oxygen reachs the blood through the skin [thats why the skin comes off so easly, is simply attached but the blood vessles].

Above a given mass, the volume to surface area means that other mean of "breathing" must be used. So, breathing through the skin can be only achieved by very small animals. Larger ones must use more efficient means, like lungs....

I think it may be a defence from attacks from behind, like who would be dumb enough to jump on the spines. another thing is why would they need anything to cool themselves, the hoter the better for them.

Becuase they could literally cook themselves or injure themselves from the heat.

They can survive molten lead, the one in the therd movie did and didn't seem hurt just pissed off.

Quote:

Insects breath through their skin.

Actually we are both right.
According to:http://www.earthlife.net/insects/anatomy.html

Insects have no lungs! Most insects breath passively through their spiracles (special openings in the side of there cuticle) and the air reaches the body by means of a series of smaller and smaller pipes called 'Trachea'. Diffusion of gases is effective over small distances but not over larger ones, this is one of the reasons insects are all relatively small.
Insects which do not have spiracles and tracheae breath directly through their skins.

In AVP:EX the Carrier uses the spines as a way to mobilize impregnation. The facehugger need only to latch on and it the carrier supplies it with a chemical (Name forgotten) and when it comes close to a host....SHAKKK!

Quote:

Actually we are both right. According to:http://www.earthlife.net/insects/anatomy.html Insects have no lungs! Most insects breath passively through their spiracles (special openings in the side of there cuticle) and the air reaches the body by means of a series of smaller and smaller pipes called 'Trachea'. Diffusion of gases is effective over small distances but not over larger ones, this is one of the reasons insects are all relatively small. Insects which do not have spiracles and tracheae breath directly through their skins.

Also, most amphibians intake the majority of their oxygen requirements through their skin. That

I think it has to to withe cooling too. Cant think on anything better than that.

hmm... i think that they are for blending alien to nest..... or it secretes that secretion from those tubes..