In the movies you only ever see eggs lain in humans and one predator. So theorectically could a facehugger latch onto a cat or a zoo animal? Is there any particular reason why they couldn't? And finally would it look different than a normal human-alien offspring similar to how the alien-predator creature was different?
In Alien3 the xenomorph is implanted into a dog, and as you suspected the resulting alien different from the human-form variety. Although still the same general human shape, it moves in a much more animalistic fashion.
You can also state the following: A facehugger can put an embryo into everything, though uncertain it will succeed. The form of the alien depends of the skeletal structure of the host:
- A biped, like a human, will become a bipedal alien capable of walking straight.
- A quadruped, like an ox, will become a four legged alien, probably not able to stand up.
- Though unlikely a facehugger would ever jump onto a shark, the alien would become shark shaped, maybe with a much wider head.
(I also should note that during the 90's there were non-canon toys of
- a rhino, with a much bigger body and a horn on its head.
- a bull, who's body was like a bull including two horns,
- I had a toy from a bat which had big wings.)