Incompatable

[Alienseseses]

Are there any animals a facehugger would reject? Would it jump and taste the problem or sense it already?

I doubt the huggers would hug an animal with no teeth, hands, or legs.

[SM]

Can't see why not.  Not like they're going to fight back.

I think it'd only reject hosts based on size ie. too big or too small.

[Meathead320]

How do we know that they are always intended for a face?

Is it possible that on a smaller organism it would just hug the whole body?

OR that on a larger one it would just put the DNA or embryo or however the exact method goes, into another opening?

On a world of Giants perhaps they would just let themselves get swallowed and drop the embryo off on the way down.

Just that for beings our size, or similar, the face is the most convenient method of implantation.

[gameoverman]

Because the facehuggers evolved/were created to facehug certain species.  Face it, it makes sense.

A facehugger cannot hug an ant, for example.

[gameoverman]

How do we know that they are always intended for a face?

Is it possible that on a smaller organism it would just hug the whole body?

OR that on a larger one it would just put the DNA or embryo or however the exact method goes, into another opening?

On a world of Giants perhaps they would just let themselves get swallowed and drop the embryo off on the way down.

Just that for beings our size, or similar, the face is the most convenient method of implantation.

No, it is perfectly tailored to a human size head.  A dog/ox's head is about the same size as a human (give or take), and so was the Jockey's.

[SM]

There'd up upper and lower limits for host size.

Too small and there's no room for the embryo and presumably not enough mass for the embryo to tap into.

Too big and the hugger becomes a minor irritation than a threat.